Normal adult Al content is (in mg/kg wet weight unless stated otherwise): lung: 20, bone: 1 to 3 mg/kg dry weight, liver and spleen: 1, kidney: 0.5, heart: 0.45, muscle: 0.4, brain: 0.35, and blood: 0.002. Approximately 60, 25, 10, 3, 1, 0.3, 0.25 and 0.2% of the Al body burden is in the bone, lung, muscle, liver, brain, heart, kidney and spleen, respectively (Yokel 1997; Priest 2004). Aluminum localizes at the mineralization front and in osteoid of bone. Aluminum in lung may be from environmentally-derived particles, occupational exposure, and distribution from blood. Approximately 80% of an intravenous dose of aluminum citrate was excreted within a week, suggesting the remainder was retained within the body, some of which was excreted over a longer time (Priest et al. 1995). This indicates that Al accumulates in the body during continuous intake, even in subjects with normal renal function. Brain, bone, liver and serum Al concentrations increase with age (Stitch 1957; Zapatero et al. 1995; Markesbery et al. 1984; Roider and Drasch 1999; Shimizu et al. 1994; Hellström et al. 2005).

The terminal half-life (t½) of Al has been found to be quite long in the rat and human (reviewed in (Krewski et al. 2007)). The whole-body t½ was estimated to be ~50 years in one human who received an intravenous injection of 26Al citrate, based on whole-body 26Al monitoring (Priest 2004). The t½ of Al in the rat brain has been estimated to be from ~ 150 days to considerably greater (Yokel et al., 2001b; Yumoto et al., 2003). The lack of a good understanding of allometric scaling of metal elimination rates for rat to human make it difficult to predict the human brain Al t½. Given the large percentage of Al in bone, it probably drives the Al concentration and elimination t½ throughout the body.

Aluminum in Food – The Nature and Contribution of Food Additives 219

patients lack the primary route of Al elimination, renal function. Exposure to lower levels of Al than those that caused Al-induced encephalopathy can produce a low turnover bone

Aluminum-induced low-turnover bone disease is manifest as osteomalacia and an adynamic bone disease (Bushinsky 1997). Aluminum-induced bone disease in dialysis patients is seen when serum Al is > 30 μg/L and when stains show Al at 30% of the

A microcytic, hypochromic anemia is associated with elevated plasma Al in chronic renal

Aluminum has been implicated in the etiology of Alzheimer's disease (AD) (Kawahara 2005; Spencer 2000; Gupta et al. 2005; Krewski et al. 2007; Bondy 2010; Tomljenovic 2011). Hallmark neuropathological signs include neurofibrillary tangles (NFTs), senile plaques (SP), and cerebrovascular amyloid. Early onset AD usually has a familial link, due to gene mutations which result in increased secretion of neurotoxic amyloid β protein (Aβ). No specific gene mutations have been associated with late-onset/sporadic forms of AD which account for 85 to 95% of AD cases. The lack of identified hereditary links for the majority of AD cases suggests environmental factors are likely to interact with other factors to cause this disease. Aluminum is one of the suggested environmental contributors. The genesis of the hypothesis that Al plays a role in the etiology of AD was an observation reported in 1965 of neurofibrillary degeneration in rabbit brain after intracerebral Al injection, which resembled, but was not identical to, the NFTs of AD (Klatzo, Wisniewski, and Streicher 1965). Similarly, the neuropathology in dialysis encephalopathy is different from that seen in AD. The observation of elevated Al in post-mortem brain samples (that typically weighed scores of milligrams) of humans with AD reported in 1973 was interpreted as suggesting a role for Al in AD (Crapper, Krishnan, and Dalton 1973). This was followed by many studies, some of which found a few-fold or smaller increase of the Al concentration in AD victim brains than in controls, and some which did not. Studies investigating an elevated level of Al in AD brain using microprobe techniques, such as energy dispersive (electron probe) X-ray microanalysis, secondary ion mass spectrometry, and laser microprobe mass spectroscopy which can quantify Al within a cell, NFT or SP, as well as Al-selective stains, have also produced mixed results (Yokel 2000). If Al is elevated in AD brain, it is not reflected in cerebrospinal fluid Al, which has generally not been found to be elevated (Kapaki et al. 1993). Even if Al is elevated in AD brain, it does not prove cause and effect. The neuronal degeneration of AD may result in accumulation

Another approach to address the potential role of Al in AD is the epidemiological study of the association between the concentration of Al in drinking water and AD incidence, comparing geographic regions where drinking water Al concentrations differ. Again, the

trabecular bone surface (Landeghem et al. 1998; Malluche and Monier-Faugere 1994).

**12.3 Evidence for and against a role of aluminum in Alzheimer's Disease**

disease and a microcytic anemia.

**12.1 Aluminum-induced bone disease**

**12.2 Aluminum-Induced microcytic anemia**

failure patients (Jeffery et al. 1996).

of metals, such as Al.

#### **10.3 Biotransformation**

Aluminum associates avidly with transferrin in the blood, which binds > 90 of Al in the blood. In the cerebrospinal fluid, and presumably brain extracellular fluid, ~90 of the Al is believed to be associated with citrate (calculated by Dr. Wesley Harris; Yokel and McNamara 2001).

#### **10.4 Excretion**

The kidneys account for > 95% of Al excretion, presumably by glomerular filtration of aluminum citrate. Humans who daily consume 3.5 to 10 mg of Al would be expected to excrete 4 to 12 μg, generating a typical urinary Al concentration of 2 to 10 μg/L. Reduced or absent renal function creates the risk of Al accumulation and toxicity. The biliary route accounts for most of the remaining excreted Al.

#### **11. The most susceptible population to aluminum toxicity**

Those who have impaired or no renal function are at the greater risk of Al toxicity because of their reduced ability to excrete it. In a study, patients with chronic renal insufficiency who used Al kitchen utensils for > 1 year were divided into two groups, one that continued to do so for 3 months; the other used stainless steel utensils. The latter group showed a significantly greater decrease in serum Al and daily urine Al excretion. These results suggest Al kitchen utensils may be a significant Al source for this population (Lin et al. 1997). When foods provide more Al in the diet than cookware, as is usually the case, one might expect foods that contain considerable Al to have an even greater contribution to the Al body burden of patients with chronic renal insufficiency than produced by Al kitchen utensils.

#### **12. The primary known adverse health effects of aluminum in the human**

There is no good evidence that Al is essential or beneficial for the human. Aluminum can produce toxicity to the central nervous, skeletal and hematopoietic systems. It can produce an encephalopathy in renal-impaired humans (dialysis encephalopathy), cognitive deficits in young children, a low-turnover bone disease, a microcytic hypochromic anemia, and has been implicated as an environmental factor that may contribute to some neurodegenerative diseases, including Alzheimer's disease.

The toxicity of Al has been extensively reviewed by the World Health Organization, for the US Department of Health and Human Services, and most extensively by a multi-national group led by Daniel Krewski (WHO 1997; ATSDR 2008; Krewski et al. 2007). When hemodialysis was initially extensively used, some patients developed a progressive encephalopathy that was fatal within 6 months. Dialysis (associated) encephalopathy (aka: dialysis dementia) is characterized by dyspraxia, dysarthria, emotional changes, trembling, ataxia, myoclonus, and fatal convulsions. It is associated with elevated levels of Al in the brain, and serum Al > 80 μg/L (Nieboer et al. 1995). Dialysis encephalopathy was due to Al contamination of the dialysis fluids and administration of Al-based phosphate binders to form an insoluble Al phosphate in the intestine, facilitating phosphate elimination, a goal not well achieved by dialysis. The renal dialysis patient is highly susceptible to Al accumulation and toxicity from Al in dialysis fluids because the Al can diffuse across the dialysis membrane, it rapidly and very strongly binds to transferrin in the blood, and these patients lack the primary route of Al elimination, renal function. Exposure to lower levels of Al than those that caused Al-induced encephalopathy can produce a low turnover bone disease and a microcytic anemia.

#### **12.1 Aluminum-induced bone disease**

218 Food Additive

Aluminum associates avidly with transferrin in the blood, which binds > 90 of Al in the blood. In the cerebrospinal fluid, and presumably brain extracellular fluid, ~90 of the Al is believed to be associated with citrate (calculated by Dr. Wesley Harris; Yokel and

The kidneys account for > 95% of Al excretion, presumably by glomerular filtration of aluminum citrate. Humans who daily consume 3.5 to 10 mg of Al would be expected to excrete 4 to 12 μg, generating a typical urinary Al concentration of 2 to 10 μg/L. Reduced or absent renal function creates the risk of Al accumulation and toxicity. The biliary route

Those who have impaired or no renal function are at the greater risk of Al toxicity because of their reduced ability to excrete it. In a study, patients with chronic renal insufficiency who used Al kitchen utensils for > 1 year were divided into two groups, one that continued to do so for 3 months; the other used stainless steel utensils. The latter group showed a significantly greater decrease in serum Al and daily urine Al excretion. These results suggest Al kitchen utensils may be a significant Al source for this population (Lin et al. 1997). When foods provide more Al in the diet than cookware, as is usually the case, one might expect foods that contain considerable Al to have an even greater contribution to the Al body burden of patients with chronic renal insufficiency than produced by Al kitchen utensils.

**12. The primary known adverse health effects of aluminum in the human**

There is no good evidence that Al is essential or beneficial for the human. Aluminum can produce toxicity to the central nervous, skeletal and hematopoietic systems. It can produce an encephalopathy in renal-impaired humans (dialysis encephalopathy), cognitive deficits in young children, a low-turnover bone disease, a microcytic hypochromic anemia, and has been implicated as an environmental factor that may contribute to some neurodegenerative

The toxicity of Al has been extensively reviewed by the World Health Organization, for the US Department of Health and Human Services, and most extensively by a multi-national group led by Daniel Krewski (WHO 1997; ATSDR 2008; Krewski et al. 2007). When hemodialysis was initially extensively used, some patients developed a progressive encephalopathy that was fatal within 6 months. Dialysis (associated) encephalopathy (aka: dialysis dementia) is characterized by dyspraxia, dysarthria, emotional changes, trembling, ataxia, myoclonus, and fatal convulsions. It is associated with elevated levels of Al in the brain, and serum Al > 80 μg/L (Nieboer et al. 1995). Dialysis encephalopathy was due to Al contamination of the dialysis fluids and administration of Al-based phosphate binders to form an insoluble Al phosphate in the intestine, facilitating phosphate elimination, a goal not well achieved by dialysis. The renal dialysis patient is highly susceptible to Al accumulation and toxicity from Al in dialysis fluids because the Al can diffuse across the dialysis membrane, it rapidly and very strongly binds to transferrin in the blood, and these

**10.3 Biotransformation**

accounts for most of the remaining excreted Al.

diseases, including Alzheimer's disease.

**11. The most susceptible population to aluminum toxicity**

McNamara 2001).

**10.4 Excretion**

Aluminum-induced low-turnover bone disease is manifest as osteomalacia and an adynamic bone disease (Bushinsky 1997). Aluminum-induced bone disease in dialysis patients is seen when serum Al is > 30 μg/L and when stains show Al at 30% of the trabecular bone surface (Landeghem et al. 1998; Malluche and Monier-Faugere 1994).

#### **12.2 Aluminum-Induced microcytic anemia**

A microcytic, hypochromic anemia is associated with elevated plasma Al in chronic renal failure patients (Jeffery et al. 1996).

#### **12.3 Evidence for and against a role of aluminum in Alzheimer's Disease**

Aluminum has been implicated in the etiology of Alzheimer's disease (AD) (Kawahara 2005; Spencer 2000; Gupta et al. 2005; Krewski et al. 2007; Bondy 2010; Tomljenovic 2011). Hallmark neuropathological signs include neurofibrillary tangles (NFTs), senile plaques (SP), and cerebrovascular amyloid. Early onset AD usually has a familial link, due to gene mutations which result in increased secretion of neurotoxic amyloid β protein (Aβ). No specific gene mutations have been associated with late-onset/sporadic forms of AD which account for 85 to 95% of AD cases. The lack of identified hereditary links for the majority of AD cases suggests environmental factors are likely to interact with other factors to cause this disease. Aluminum is one of the suggested environmental contributors. The genesis of the hypothesis that Al plays a role in the etiology of AD was an observation reported in 1965 of neurofibrillary degeneration in rabbit brain after intracerebral Al injection, which resembled, but was not identical to, the NFTs of AD (Klatzo, Wisniewski, and Streicher 1965). Similarly, the neuropathology in dialysis encephalopathy is different from that seen in AD. The observation of elevated Al in post-mortem brain samples (that typically weighed scores of milligrams) of humans with AD reported in 1973 was interpreted as suggesting a role for Al in AD (Crapper, Krishnan, and Dalton 1973). This was followed by many studies, some of which found a few-fold or smaller increase of the Al concentration in AD victim brains than in controls, and some which did not. Studies investigating an elevated level of Al in AD brain using microprobe techniques, such as energy dispersive (electron probe) X-ray microanalysis, secondary ion mass spectrometry, and laser microprobe mass spectroscopy which can quantify Al within a cell, NFT or SP, as well as Al-selective stains, have also produced mixed results (Yokel 2000). If Al is elevated in AD brain, it is not reflected in cerebrospinal fluid Al, which has generally not been found to be elevated (Kapaki et al. 1993). Even if Al is elevated in AD brain, it does not prove cause and effect. The neuronal degeneration of AD may result in accumulation of metals, such as Al.

Another approach to address the potential role of Al in AD is the epidemiological study of the association between the concentration of Al in drinking water and AD incidence, comparing geographic regions where drinking water Al concentrations differ. Again, the

Aluminum in Food – The Nature and Contribution of Food Additives 221

accumulation to develop metabolic bone disease, cholestatic hepatitis, and reduction of mental development. To address this concern the U.S. Food and Drug Administration adopted a labeling requirement for Al in large and small volume parenterals used to

For the typical human, food additives provide the largest source of daily Al intake, exceeding water by several orders of magnitude, the latter having been implicated as a contributing factor to dementia, specifically Alzheimer's disease. The food additive contributing the greatest amount of Al to the diet is SALP, used in its acidic form as a leavening agent in baked goods and in its basic form as an emulsifying agent in cheese. Acidic SALP is an approved food additive in most countries. Basic SALP is approved for use in many fewer countries. There has been debate for a century about the safety of Al as a food additive. This debate continues, and is reflected in recently changed established tolerable intake and minimal risk levels and changes under consideration. It has been noted that there is no good evidence of adverse health effects attributed to Al from food, that this issue has not been adequately directly assessed, and that those who lack good renal function, and therefore unable to efficiently eliminate Al, are at greatest risk of Al-induced toxicity, perhaps from food. As with the controversy concerning a possible role of Al in the etiology of Alzheimer's disease, the controversy about possible adverse effects of Al as a food additive will continue until more definitive demonstration of safety or untoward effect is

Alfrey, A. C., G. R. LeGendre, and W. D. Kaehny. 1976. The dialysis encephalopathy

Allen, J. L., and F. J. Cumming. 1998. Aluminum in the food and water supply: An

Anon. 1913. Culinary and chemical experiments with aluminium cooking vessels. *The Lancet*

ATSDR. 2008. Toxicological profile for aluminum. US Department of Health and Human Services, Public Health Service, Agency of Toxic Substances and Disease Registry. Biego, G. H., M. Joyeux, P. Hartemann, and G. Debry. 1998. Daily intake of essential

Bohrer, D., S. M. Oliveira, S. C. Garcia, P. C. Nascimento, and L. M. Carvalho. 2010.

Bondy, S. C. 2010. The neurotoxicity of environmental aluminum is still an issue.

Bushinsky, D. A. 1997. Bone disease in moderate renal failure: cause, nature and prevention.

Australian perspective. Melbourne: Urban Water Research Association of

minerals and metallic micropollutants from foods in France. *Sci Total Environ* 217

Aluminum loading in preterm neonates revisited. *J Pediatr Gastroenterol Nutr* 51

syndrome. Possible aluminum intoxication. *NEJM* 294 (4):184-188.

Australia, a division of Water Services Association of Australia.

Anon. 1998. Rhodia adds SALP. *Chemical Week*, Sep. 23, 1998, 73.

prepare total parenteral nutrition solutions. This has not solved the problem.

**15. Summary**

demonstrated.

**16. References**

i:843.

(1-2):27-36.

(2):237-241.

*Neurotoxicology* 31 (5):575-581.

*Ann Rev Med* 48:167-176.

results of many such studies are not consistent. The majority reported an increased risk of AD associated with higher drinking water Al concentration. Some of the differences were statistically significant. A major review published in 2007 conducted a risk characterization of the route of Al intake, the exposure level of concern, and Al exposure in the general population and calculated a margin of exposure (ratio of the exposure level of concern to the exposure level) (Krewski et al. 2007). The exposure level of concern was based on an epidemiological study that showed a relative risk of AD of 2.14 associated with a drinking water Al concentration > 100 μg/L (Rondeau et al. 2000).

Given that Al bioavailability from water is not considerably greater than from food, studies assessing a putative link between Al in drinking water and AD might be mis-focused, and studies investigating a possible association between Al in food and cognitive impairment, dementia and AD might be more relevant. However, these are much more difficult to conduct, due to the multiple sources of Al in foods. It has been stated by US FDA employees that no clinical syndrome has been noted for the very low intake of dietary Al (Humphreys and Bolger 1997). It was also suggested that the risk of adverse effects of dietary Al, if there are any, is extremely low (Soni et al. 2001). The only published study addressing the potential association between Al in food and dementia was a preliminary study of 23 newlydiagnosed AD patients and 23 matched non-demented controls to ascertain the relationship between consumption of foods generally high in Al during the previous 5 years and dementia. The results showed increased odds ratios for many food categories. However, the results were only significant for the category containing pancakes, waffles, biscuits, muffins, cornbread and corn tortillas (Rogers and Simon 1999).

#### **13. Determination of aluminum body burden and its treatment**

Determination of elevated body burden of Al might be made by quantification of Al in blood. However, this is quite difficult because the blood Al concentration of the normal healthy human is very low, thought to be < 6 μg/ml, and probably ~ 2 μg/ml (Daniela et al. 2002; House 1992; Valkonen and Aitio 1997), and due to its ubiquitous nature, sample contamination is very easily obtained. The desferrioxamine test, a single injection of 5 mg/kg this chelator, has been used to assess Al body burden, as evidenced by an increase in serum Al and urinary Al clearance. The test dose is used because steady-state serum Al concentrations do not correlate well with the Al deposition in bone and soft tissues that results from long-term Al exposure (Yokel 2002; Seo et al. 2007). Up to 5 mg/kg of desferrioxamine once or twice weekly has been shown to be safe and effective for long-term treatment of Al overload, and reduction of Al-induced encephalopathy, bone disease and anemia (Kan et al. 2010).

#### **14. Aluminum toxicity in the premature infant**

Another high risk group for Al toxicity is premature infants who are fed intravenously, because they do not tolerate oral feeding. The total parenteral nutrition feeding solutions given intravenously can contain significant Al, which is primarily derived from the calcium gluconate and phosphates used as components of the solution. As this feeding solution is given intravenously, and therefore 100% bioavailable, to premature infants whose kidneys are not fully matured and therefore less able to excrete the Al, they are at risk of sufficient Al accumulation to develop metabolic bone disease, cholestatic hepatitis, and reduction of mental development. To address this concern the U.S. Food and Drug Administration adopted a labeling requirement for Al in large and small volume parenterals used to prepare total parenteral nutrition solutions. This has not solved the problem.

#### **15. Summary**

220 Food Additive

results of many such studies are not consistent. The majority reported an increased risk of AD associated with higher drinking water Al concentration. Some of the differences were statistically significant. A major review published in 2007 conducted a risk characterization of the route of Al intake, the exposure level of concern, and Al exposure in the general population and calculated a margin of exposure (ratio of the exposure level of concern to the exposure level) (Krewski et al. 2007). The exposure level of concern was based on an epidemiological study that showed a relative risk of AD of 2.14 associated with a drinking

Given that Al bioavailability from water is not considerably greater than from food, studies assessing a putative link between Al in drinking water and AD might be mis-focused, and studies investigating a possible association between Al in food and cognitive impairment, dementia and AD might be more relevant. However, these are much more difficult to conduct, due to the multiple sources of Al in foods. It has been stated by US FDA employees that no clinical syndrome has been noted for the very low intake of dietary Al (Humphreys and Bolger 1997). It was also suggested that the risk of adverse effects of dietary Al, if there are any, is extremely low (Soni et al. 2001). The only published study addressing the potential association between Al in food and dementia was a preliminary study of 23 newlydiagnosed AD patients and 23 matched non-demented controls to ascertain the relationship between consumption of foods generally high in Al during the previous 5 years and dementia. The results showed increased odds ratios for many food categories. However, the results were only significant for the category containing pancakes, waffles, biscuits, muffins,

Determination of elevated body burden of Al might be made by quantification of Al in blood. However, this is quite difficult because the blood Al concentration of the normal healthy human is very low, thought to be < 6 μg/ml, and probably ~ 2 μg/ml (Daniela et al. 2002; House 1992; Valkonen and Aitio 1997), and due to its ubiquitous nature, sample contamination is very easily obtained. The desferrioxamine test, a single injection of 5 mg/kg this chelator, has been used to assess Al body burden, as evidenced by an increase in serum Al and urinary Al clearance. The test dose is used because steady-state serum Al concentrations do not correlate well with the Al deposition in bone and soft tissues that results from long-term Al exposure (Yokel 2002; Seo et al. 2007). Up to 5 mg/kg of desferrioxamine once or twice weekly has been shown to be safe and effective for long-term treatment of Al overload, and reduction of Al-induced encephalopathy, bone disease and

Another high risk group for Al toxicity is premature infants who are fed intravenously, because they do not tolerate oral feeding. The total parenteral nutrition feeding solutions given intravenously can contain significant Al, which is primarily derived from the calcium gluconate and phosphates used as components of the solution. As this feeding solution is given intravenously, and therefore 100% bioavailable, to premature infants whose kidneys are not fully matured and therefore less able to excrete the Al, they are at risk of sufficient Al

water Al concentration > 100 μg/L (Rondeau et al. 2000).

cornbread and corn tortillas (Rogers and Simon 1999).

**14. Aluminum toxicity in the premature infant**

anemia (Kan et al. 2010).

**13. Determination of aluminum body burden and its treatment**

For the typical human, food additives provide the largest source of daily Al intake, exceeding water by several orders of magnitude, the latter having been implicated as a contributing factor to dementia, specifically Alzheimer's disease. The food additive contributing the greatest amount of Al to the diet is SALP, used in its acidic form as a leavening agent in baked goods and in its basic form as an emulsifying agent in cheese. Acidic SALP is an approved food additive in most countries. Basic SALP is approved for use in many fewer countries. There has been debate for a century about the safety of Al as a food additive. This debate continues, and is reflected in recently changed established tolerable intake and minimal risk levels and changes under consideration. It has been noted that there is no good evidence of adverse health effects attributed to Al from food, that this issue has not been adequately directly assessed, and that those who lack good renal function, and therefore unable to efficiently eliminate Al, are at greatest risk of Al-induced toxicity, perhaps from food. As with the controversy concerning a possible role of Al in the etiology of Alzheimer's disease, the controversy about possible adverse effects of Al as a food additive will continue until more definitive demonstration of safety or untoward effect is demonstrated.

#### **16. References**

Aluminum in Food – The Nature and Contribution of Food Additives 223

Golub, M. S., and S. L. Germann. 2001. Long-term consequences of developmental exposure

Gramiccioni, L., G. Ingrao, M. R. Milana, P. Santaroni, and G. Tomassi. 1996. Aluminium

Gupta, Veer Bala, S. Anitha, M. L. Hegde, L. Zecca, R. M. Garruto, R. Ravid, S. K. Shankar,

Hohl, Ch., P. Gerisch, G. Korschinek, E. Nolte, and T. H. Ittel. 1994. Medical application of

Horemans, B., A. Worobiec, A. Buczynska, K. Van Meel, and R. Van Grieken. 2008. Airborne

House, R. A. 1992. Factors affecting plasma aluminum concentrations in nonexposed

Humphreys, S.H. 1992. The GRAS review process and aluminum salts. Paper read at

Humphreys, S., and P. M. Bolger. 1997. A public health analysis of dietary aluminium. In

Inoue, T., H. Ishiwata, and K. Yoshihara. 1988. Aluminum levels in food-simulating solvents and various foods cooked in aluminum pans. *J Agric Food Chem* 36:599-601. Jeffery, E. H., K. Abreo, E. Burgess, J. Cannata, and J. L. Greger. 1996. Systemic aluminum

Jones, K. C., and B. G. Bennett. 1986. Exposure of man to environmental aluminium--an exposure commitment assessment. *Sci Total Environment* 52 (1-2):65-82. Jorhem, L., and G. Haegglund. 1992. Aluminium in foodstuffs and diets in Sweden. *Zeitschrift für Lebensmittel-Untersuchung und-Forschung* 194 (1):38-42. Kan, W. C., C. C. Chien, C. C. Wu, S. B. Su, J. C. Hwang, and H. Y. Wang. 2010. Comparison

Kapaki, E. N., C. P. Zournas, I. T. Segdistsa, D. S. Xenos, and C. T. Papageorgiou. 1993.

Katz, A. C., D. W. Frank, M. W. Sauerhoff, G. M. Zwicker, and R. I. Freudenthal. 1984. A 6-

Greger, J. L. 1985. Aluminum content of the American diet. *Food Technol* 39 (May):73-80. Greger, J. L., and J. E. Sutherland. 1997. Aluminum exposure and metabolism. *Crit Rev Clin*

dementia compared to controls. *Osteoporosis Int* 16 (12):1982-1988.

26Al. *Nucl Instrument Meth Physics Res* B 92:478-482.

workers. *J Occup Med* 34 (10):1013-1017.

Alfrey. Singapore, Singapore: World Scientific.

2-6, 1992, at Tampa, FL.

48 (6):649-665.

(5):1604-1608.

9):679-681.

dogs. *Food Chem Toxicol* 22 (1):7-9.

*Neurotoxicology and Teratology* 23 (4):365-72.

*Contam* 13 (7):767-774.

*Lab Sci* 34 (5):439-474.

to aluminum in a suboptimal diet for growth and behavior of Swiss Webster mice.

levels in Italian diets and in selected foods from aluminium utensils. *Food Add*

R.; Stein, P. Shanmugavelu, and K. S. Jagannatha. Rao. 2005. Aluminium in Alzheimer's disease: Are we still at a crossroad? *Cell Mol Life Sci* 62 (2):143-158. Hellström, H-O., B. Mjöberg, H. Mallmin, K. Michaëlsson. 2005. The aluminum content of

bone increases with age, but is not higher in hip fracture cases with and without

particulate matter and BTEX in office environments. *J Environ Monit* 10 (7):867-876.

Proceedings of the Second International Conference on Aluminum and Health, Feb

*Aluminium toxicity in infants' health and disease*, edited by P. F. Zatta and A. C.

toxicity: effects on bone, hematopoietic tissue, and kidney. *J Toxicol Environ Health*

of low-dose deferoxamine versus standard-dose deferoxamine for treatment of aluminium overload among haemodialysis patients. *Nephrol Dial Transplant* 25

Cerebrospinal fluid aluminum levels in Alzheimer's disease. *Biolog Psychiatry* 33 (8-

month dietary toxicity study of acidic sodium aluminium phosphate in beagle

Committee on Food Additives survey data, National Research Council (U.S.). 1984. *Poundage*

Crapper, D. R., S. S. Krishnan, and A. J. Dalton. 1973. Brain aluminum distribution in

Daniela, B. B., D. F. Antonella, L. Antonela, F. Maurizio, and P. Augusta. 2002. Aluminum

Datta, N. C. 1935. Metallic contaminations of foods. II. Effect of cooking and storage on foodstuffs in aluminum vessels. *Proc - Indian Acad Sci, Section A* 2B:322-332. Delves, H. T., C. E. Sieniawaska, and B. Suchak. 1993. Total and bioavailable aluminium in

Döllken, von. 1898. Ueber die wirkung des aluminiums mit besonderer beriicksichtigung

Ellinger, R.H. 1972. *Phosphates as food ingredients*. Edited by R. C. Weast. Cleveland, OH.:

FAO/WHO. 2006. Summary and conclusions of the sixty-seventh meeting of the Joint

FAO/WHO, Joint FAO/WHO Expert Committee on Food Additives. 2007. Evaluation of

FASEB, Life Sciences Research Office, Federation of American Societies for Experimental

Fimreite, N., O. O. Hansen, and H. C. Pettersen. 1997. Aluminum concentrations in selected

Flarend, R., T. Bin, D. Elmore, and S. L. Hem. 2001. A preliminary study of the dermal

Flarend, R. E., S. L. Hem, J. L. White, D. Elmore, M. A. Suckow, A. C. Rudy, and E. A.

Fukushima, Masako, and Akio Tanimura. 1998. Aluminium absorption by food from packaging materials. *Nippon Kasei Gakkaishi (J. Home. Econ. Jpn.)* 49 (12):1313-1317. Ganrot, P. O. 1986. Metabolism and possible health effects of aluminum. *Environmental*

Gies, W.J. 1911. Some objections to the use of alum baking-powder. *JAMA* 57:816-821. Gitelman, H. J., F. R. Alderman, M. Kurs-Lasky, and H. E. Rockette. 1995. Serum and

FAO/WHO Expert Committee on Food Additives (JECFA)

foods and beverages. *Anal Proc* 30 (9):358-360.

Academy Press.

(Suppl):S30-S31.

*Path Pharmacol* 40:98-120.

(85):511-513.

CRC Press.

*series* 940:92pp.

NTIS-PB 262 655,

*Toxicol* 39:163-168.

(2):181-191.

*Environ Contam Toxicol* 58 (1):1-7.

using 26Al. *Vaccine* 15 (12-13):1314-1318.

*Health Perspectives* 65:363-441.

*update of food chemicals, 1982.* 2 vols., PB 84-16214, Washington, D.C.: National

Alzheimer's disease and experimental neurofibrillary degeneration. *Science* 180

contamination in home parenteral nutrition patients. *JPEN J Parenter Enteral Nutr* 26

der durch das aluminium verursachten lasionen im centralnervensystem. *Arcr Exp*

certain food additives and contaminants *World Health Organization technical report*

Biology. 1975. Evaluation of the health aspects of aluminum compounds as food ingredients, Contract No. FDA 223-75-2004, U.S. FDA Report FDA/BF-77/24,

foods prepared in aluminum cookware, and its implications for human health. *Bull*

absorption of aluminium from antiperspirants using aluminum-26. *Food Chem*

Dandashli. 1997. In vivo absorption of aluminium-containing vaccine adjuvants

urinary aluminium levels of workers in the aluminium industry. *Ann Occup Hyg* 39

Aluminum in Food – The Nature and Contribution of Food Additives 225

Pierre, F., F. Baruthio, F. Diebold, and P. Biette. 1995. Effect of different exposure

Poole, R. L., L. Schiff, S. R. Hintz, A. Wong, N. Mackenzie, and J. A. Kerner, Jr. 2010.

Powell, J. J., and R. P. Thompson. 1993. The chemistry of aluminium in the gastrointestinal lumen and its uptake and absorption. *Proceed Nutri Soc* 52 (1):241-253. Priest, N. D. 1993. The bioavailability and metabolism of aluminium compounds in man.

Priest, N.D. 2004. The biological behaviour and bioavailability of aluminium in man, with

Priest, N. D., D. Newton, J. P. Day, R. J. Talbot, and A. J. Warner. 1995. Human

Priest, N. D., R. J. Talbot, D. Newton, J. P. Day, S. J. King, and L. K. Fifield. 1998. Uptake by man of aluminium in a public water supply. *Hum Exp Toxicol* 17 (6):296-301. Reilly, C. 1991. *Metal contamination of food*. Vol. Second Edition. Essex, England: Elsevier

Riihimäki, V., H. Hänninen, R. Akila, T. Kovala, E. Kuosma, H. Paakkulainen, S. Valkonen,

Rogers, M.A.M., and D.G. Simon. 1999. A preliminary study of dietary aluminium intake

Roider, G., and G. Drasch. 1999. Concentration of aluminum in human tissues -

Rondeau, V., D. Commenges, H. Jacqmin-Gadda, and J. F. Dartigues. 2000. Relation between

Rowland, M. , and T. N. Tozer. 1995. *Clinical Pharmacokinetics. Concepts and Applications*. third

Saiyed, S. M., and R. A. Yokel. 2005. Aluminium content of some foods and food products in the USA, with aluminium food additives. *Food Addit Contam* 22 (3):234-244. Scancar, J, V Stibilj, and R Milacic. 2003. Determination of aluminium in Slovenian

Schaeffer, G., G. Pontes, E. Le Breton, Ch. Oberling, and L. Thivolle. 1928. The dangers of

Seo, Y. S., H. W. Gil, J. O. Yang, E. Y. Lee, and S.-Y. Hong. 2007. The clinical study on

and risk of Alzheimer's disease. *Age Ageing* 28:205-209.

(Germany). *Trace Elem Electrolytes* 16 (2):77-86.

follow-up study. *A J Epidemiol* 152 (1):59-66.

ed. Media, PA: Williams & Wilkins.

workers. *Occupat Environ Med* 52 (6):396-403.

levels. *J Pediatr Gastroenterol Nutr* 50 (2):208-211.

*Proceed Nutr Soc* 52 (1):231-240.

(3):287-293.

(2):118-130.

151-157.

439.

*Hygiene* 28:92-99.

Science Publishers Ltd.

update. *J Environ Monit* 6 (5):375-403.

compounds on urinary kinetics of aluminium and fluoride in industrially exposed

Aluminum content of parenteral nutrition in neonates: measured versus calculated

special reference to studies employing aluminium-26 as a tracer: review and study

metabolism of aluminium-26 and gallium-67 injected as citrates. *Hum Exp Toxicol* 14

and B. Engström. 2000. Body burden of aluminum in relation to central nervous system function among metal inert-gas welders. *Scand J Work, Environ Health* 26

investigations on an occupationally non-exposed population in Southern Bavaria

aluminum concentrations in drinking water and Alzheimer's disease: an 8-year

foodstuffs and its leachability from aluminium-cookware. *Food Chem* 85 (1):

certain mineral baking powders based on alum, when used for human nutrition. *J*

aluminum levels in patients undergoing hemodialysis. *Korean J Nephrol* 26 (4):435-

Kawahara, M. 2005. Effects of aluminum on the nervous system and its possible link with

Klatzo, I., H. Wisniewski, and E. Streicher. 1965. Experimental production of neurofibrillary degeneration. 1. Light microscopic observation. *J Pathology* 24:187-199. Kovalchik, M. T., W. D. Kaehny, A. P. Hegg, J. T. Jackson, and A. C. Alfrey. 1978. Aluminum

Krewski, D., R. A. Yokel, E. Nieboer, D. Borchelt, J. Cohen, J. Harry, S. Kacew, J. Lindsay, A.

Landeghem, G. F., P. C. D'Haese, L. V. Lamberts, L. Djukanovic, S. Pejanovic, W. G.

Lione, A. 1983. The prophylactic reduction of aluminium intake. *Food Chem Toxicol* 21

Lopez, F. E., C. Cabrera, M. L. Lorenzo, and M. C. Lopez. 2002. Aluminum levels in

Malluche, H. H., and M. C. Monier-Faugere. 1994. The role of bone biopsy in the management of patients with renal osteodystrophy. *J Am Soc Nephrol* 4 (9):1631-42. Markesbery, W. R., W. D. Ehmann, M. Alauddin, and T. I. M. Hossain. 1984. Brain trace

Müller, M., M. Anke, and H. Illing-Günther. 1998. Aluminium in foodstuffs. *Food Chem* 61

NAS, Committee on the GRAS List Survey-Phase III - Estimates of daily intake. 1979. The

Neelam, M.S. Bamji, and M. Kaladhar. 2000. Risk of aluminium burden in the Indian population: contribution from aluminium cookware. *Food Chem* 70:57-61. Nieboer, E., B. L. Gibson, A. D. Oxman, and J. R. Kramer. 1995. Health effects of aluminum:

Panel on Food Additives, Flavourings, Processing Aids and Food Contact Materials,

Pennington, J. A. T. 1992. Dietary exposure to aluminum. Paper read at Proceedings of the

1977 survey of industry on the use of food additives. Washington, D.C.: National

a critical review with emphasis on aluminum in drinking water. *Environ Rev* 3

European Food Safety Authority. 2008. Safety of aluminium from dietary intake[1] - Scientific Opinion of the Panel on Food Additives, Flavourings, Processing Aids and Food Contact Materials (AFC). In *Question number: EFSA-Q-2006-168, EFSA-Q-2008-254*, edited by E. F. S. Authority: EFSA Journal, doi:10.2903/j.efsa.2008.754. Pennington, J.A.T. 1987. Aluminium content of foods and diets. *Food Addit Contam* 5 (2):161-

Second International Conference on Aluminum and Health, Feb 2-6, 1992, at

element concentrations in aging. *Neurobiol Aging* 5 (1):19-28.

patients with increased bone aluminum levels. *Clin Nephrol* 50 (2):69-76. Lin, J. L., Y. J. Yang, S. S. Yang, and M. L. Leu. 1997. Aluminum utensils contribute to

M. Mahfouz, and V. Rondeau. 2007. Human health risk assessment for aluminium, aluminium oxide, and aluminium hydroxide. *J Toxicol Environ Health, Part B: Crit*

Goodman, and M. E. De Broe. 1998. Low serum aluminum values in dialysis

aluminum accumulation in patients with renal disease. *Am J Kidney Dis* 30 (5):653-

convenience and fast foods: in vitro study of the absorbable fraction. *Sci Total*

neurodegenerative diseases. *J Alzheimers Dis* 8 (2):171-182.

kinetics during hemodialysis. *J Lab Clin Med* 92:712-720.

*Rev* 10, Suppl 1:1-269.

*Environment* 300 (1-3):69-79.

658.

(1):103-109.

(4):419-428.

(1):29-81.

232.

Tampa, Fl.

Academy of Sciences

Aluminum in Food – The Nature and Contribution of Food Additives 227

Wang, L, D Z Su, and Y F Wang. 1994. Studies on the aluminium content in Chinese foods

WHO, International Programme on chemical safety. 1997. *Aluminium*. Vol. 194, *Environmental*

Wiley, H. W. 1929. *History of a crime against the food law: The amazing story of the national food*

Wuhrer, J. 1939. Consideration of aluminum from the sanitary, especially from the food-

Yokel, R. A. 1997. The metabolism and toxicokinetics of aluminum relevant to neurotoxicity.

Yokel, R. A. 2000. The toxicology of aluminum in the brain: A review. *NeuroToxicology* 21

Yokel, R.A. 2002. Aluminum chelation principles and recent advances. *Coord Chem Rev*

Yokel, R.A., and R. L. Florence. 2006. Aluminum bioavailability from the approved food

Yokel, R.A., and M.S. Golub, eds. 1997. *Research issues in aluminum toxicity*. Washington,

Yokel, R.A., C.L. Hicks, and R. L. Florence. 2008. Aluminum bioavailability from basic

Yokel, R.A., and P.J. McNamara. 2001. Aluminum toxicokinetics: An updated mini-review.

Yokel, R.A., S.S. Rhineheimer, R.D. Brauer, P. Sharma, D. Elmore, and P.J. McNamara.

Yokel, R.A., S.S. Rhineheimer, P. Sharma, D. Elmore, and P.J. McNamara. 2001b. Entry, half-

Ysart, G., P. Miller, M. Croasdale, H. Crews, P. Robb, M. Baxter, C. de L'Argy, and N.

Yumoto, S., H. Nagai, K. Kobayashi, A. Tamate, S. Kakimi, and H. Matsuzaki. 2003. 26Al

Zapatero, M. D., A. Garcia de Jalon, F. Pascual, M. L. Calvo, J. Escanero, and A. Marro. 1995.

*Health Criteria*. Geneva: World Health Organization. Wiley, H. W. 1928. The baking powder controversy. *Science* 68:159-162.

hygienic point of view. *Korrosion und Metallschutz* 15:15-24.

baked good, is lower than from water. *Toxicol* 227:86-93.

incorporated in cheese. *Food Chem Toxicol* 46:2261-2266.

Ota and M. A. Verity. Boca Raton: CRC Press.

*Environ Sci: BES* 7 (1):91-99.

foods.

(5):813-828.

228:97-113.

101.

D.C.: Taylor & Francis.

*Pharmacol Toxicol* 88:159-167.

exposure. Toxicol Sci 64:77-82.

*Addit Contamin* 17 (9):775-786.

*Trace Element Res* 47 (1-3):235-240.

Biochem 97 (1):155-160.

and the maximum permitted levels of aluminum in wheat flour products. *Biomed*

*and drugs law intended to protect the health of the people, perverted to protect adulteration of foods and drugs*. Washington, 413 pp, pages 400-402 on objection to use of alum in

In *Mineral and Metal Neurotoxicology*, pp.81-89, edited by M. Yasui, M. Strong, K.

additive leavening agent acidic sodium aluminum phosphate, incorporated into a

sodium aluminum phosphate, an approved food additive emulsifying agent,

2001a. Aluminum bioavailability from drinking water is very low and is not appreciably influenced by stomach contents or water hardness. *Toxicology* 161:93-

life and desferrioxamine-accelerated clearance of brain aluminum after a single 26Al

Harrison. 2000. 1997 UK Total Diet Study--dietary exposures to aluminium, arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, tin and zinc. *Food*

incorporation into the brain of suckling rats through maternal milk. J Inorg

Serum aluminum levels in Alzheimer's disease and other senile dementias. *Biol*

Severus, H. 1989. The use of aluminium - especially as packaging material - in the food

Sherlock, J.C. 1989. Aluminium in foods and the diet. In *Aluminium in food and the*

Sjögren, B., C.-G. Elinder, A. Iregren, D. R. C. McLachlan, and V. Riihimäki. 1997.

Smith, E. E. 1928. *Aluminum compounds in food, including a digest of the report of the Referee*

Soni, M. G., S. M. White, W. G. Flamm, and G. A. Burdock. 2001. Safety evaluation of dietary

Speerhas, R. A., and D. L. Seidner. 2007. Measured versus estimated aluminum content of parenteral nutrient solutions. *Am J Health-System Pharmacy* 64 (4):740-746. Spencer, P.S. 2000. Aluminum and its compounds. In *Experimental and clinical*

Stauber, J. L., T. M. Florence, C. M. Davies, M. S. Adams, and S. J. Buchanan. 1999.

Stitch, S.R. 1957. Trace elements in human tissues. 1. A semi-quantitative spectrographic

Takeda, Y., Y Kawamura, and T Yamada. 1998. [Dissolution of aluminium from aluminium

Tomljenovic, L. 2011. Aluminum and Alzheimer's disease: after a century of controversy, is

Tracor-Jitco. 1973. Scientific literature reviews on generally recognized as safe (GRAS) food

United Kingdom Ministry of Agriculture Fisheries and Food, (MAFF) 1993. Aluminium in

Valkonen, S., and A Aitio. 1997. Analysis of aluminium in serum and urine for the biomonitoring of occupational exposure. *Sci Total Environ* 199:103-110.

ingredients - aluminum compounds. Rockville, MD: Tracor-Jitco.

Chemistry, Thomas Graham House.

subjects]. *Jap J Geriatrics* 31:950-960.

*health of man*. New York: P.B. Hoeber, Inc., 378 pp.

*Zasshi (J Food Hygienic Society Japan)* 39 (4):266-271.

there a plausible link? *J Alzheimers Dis* 23 (4):567-98.

aluminum. *Reg Toxicol Pharmacol* 33 (1):66-79.

D.C.: Taylor & Francis.

University Press.

Stationery Office).

*Water Works Association)* 91:84-93.

survey. *Biochem J* 67:97-109.

chemistry. In *Aluminium in food and the environment; the proceedings of a symposium organised by the environment and Food Chemistry groups of the Industrial Division of the Royal Society of Chemistry, London, 17th May 1988 - (Special publication, no. 73),* pp. 88- 101, edited by R. C. Massey and D. Taylor. Cambridge: The Royal Society of

*environment; the proceedings of a symposium organised by the environment and Food Chemistry groups of the Industrial Division of the Royal Society of Chemistry, London, 17th May 1988 - (Special publication, no. 73),* pp. 68-75, edited by R. C. Massey and D. Taylor. Cambridge: The Royal Society of Chemistry, Thomas Graham House. Shimizu, H, T Mori, M Koyama, M Sekiya, and H Ooami. 1994. [A correlative study of the

aluminum content and aging changes of the brain in non-demented elderly

Occupational aluminum exposure and its health effects. pp. 165-183, In *Research Issues in Aluminum Toxicity*, edited by R. A. Yokel and M. S. Golub. Washington,

*board of scientific experts on the influence of aluminum compounds on the nutrition and*

*neurotoxicology*, edited by P. S. Spencer and H. H. Schaumburg. New York: Oxford

Bioavailability of Al in alum-treated drinking water. *Journal AWWA (American*

foil into foods and effect of food components on the dissolution]. *Shokuhin Eiseigaku*

food. The thirty ninth report of the Steering Group on Chemical Aspects of Food Surveillance. Food Surveillance Paper No. 39. London: HMSO (Her Magesty's

**13**

*USA*

**The Use of Blood and**

**Derived Products as Food Additives**

*420 Sandels Building Florida State University, Tallahassee, Florida*

Blood is a rich source of iron and proteins of high nutritional and functional quality. Because of the high protein content of blood, generally about 18% [1], it is sometimes referred to as "liquid protein" [2]. It has been estimated that the approximately 1,500,000 tons of porcine blood produced yearly in China has a protein content equivalent to that of 2,000,000 tons of meat or 2,500,000 tons of eggs [3]. Thus, a valuable protein source is lost if animal blood is discarded as waste and this is compounded by the resulting serious environmental pollution problems. Many countries require that animal blood be disposed off in an environmentally friendly manner, which is a capital intensive process. Accordingly, to eliminate a sizeable pollution hazard and prevent the loss of a valuable protein source, efforts have been made to ensure the utilization of animal blood on a massive scale. A further incentive is the increased profits to be made through adding value to the blood.

The environmental, nutritional and economic benefits derived from the maximal utilization of animal blood, coupled with recent advances in blood collection and processing techniques, have led to a myriad of blood protein ingredients becoming available for use in foods and dietary supplements to serve specific needs (Table 1). By 2001, it was estimated that the food industry was utilizing 30% of the blood produced in slaughterhouses [4]. Current utilization likely surpasses this figure, though there is no data to confirm this. Plasma, the liquid portion of blood remaining after the blood cells [white blood cells (WBCs), red blood cells (RBCs), and platelets] have been removed, is most widely used in the food industry because it is neutral in taste and devoid of the dark color associated with the red blood cells (and hence whole blood) [5]. The traditional use of whole blood and its separated red blood cells as ingredients in food products is generally restricted to such products as blood sausages where the black color is both expected and acceptable [2]. The cellular portion of blood (and for that matter whole blood) has not enjoyed widespread usage in the food industry as a result of its heme component, which imparts an undesirable color, odor and metallic taste to the final product [6,7]. Even in trace quantities hemoglobin imparts a dark-brown color to foods [8]. Their use is also restricted because the cellular fraction is thought to have a higher microbial load, although this has been disproved [9]. The amount of cellular fraction-derived products used in food has traditionally been limited to 0.5 to 2% of the product in order not to jeopardize the sensory qualities of the final

**1. Introduction**

Jack Appiah Ofori and Yun-Hwa Peggy Hsieh *Department of Nutrition, Food and Exercise Sciences,*

### **The Use of Blood and Derived Products as Food Additives**

Jack Appiah Ofori and Yun-Hwa Peggy Hsieh *Department of Nutrition, Food and Exercise Sciences, 420 Sandels Building Florida State University, Tallahassee, Florida USA*

#### **1. Introduction**

228 Food Additive

Zhong, C., Y. Wang, H. Xie, Y. Zhao, F. Cai, and Z. Zhang. 1996. [A study on aluminum intake of inhabitants in Nanjing]. *Nanjng Yixueyuan Xuebao* 16 (1):50-53. Zhou, Y., W. R. Harris, and R.A. Yokel. 2008. The influence of citrate, maltolate and fluoride

concentration: A 26Al and 14C study *J Inorganic Biochem* 102:798-808.

on the gastrointestinal absorption of aluminum at a drinking water-relevant

Blood is a rich source of iron and proteins of high nutritional and functional quality. Because of the high protein content of blood, generally about 18% [1], it is sometimes referred to as "liquid protein" [2]. It has been estimated that the approximately 1,500,000 tons of porcine blood produced yearly in China has a protein content equivalent to that of 2,000,000 tons of meat or 2,500,000 tons of eggs [3]. Thus, a valuable protein source is lost if animal blood is discarded as waste and this is compounded by the resulting serious environmental pollution problems. Many countries require that animal blood be disposed off in an environmentally friendly manner, which is a capital intensive process. Accordingly, to eliminate a sizeable pollution hazard and prevent the loss of a valuable protein source, efforts have been made to ensure the utilization of animal blood on a massive scale. A further incentive is the increased profits to be made through adding value to the blood.

The environmental, nutritional and economic benefits derived from the maximal utilization of animal blood, coupled with recent advances in blood collection and processing techniques, have led to a myriad of blood protein ingredients becoming available for use in foods and dietary supplements to serve specific needs (Table 1). By 2001, it was estimated that the food industry was utilizing 30% of the blood produced in slaughterhouses [4]. Current utilization likely surpasses this figure, though there is no data to confirm this. Plasma, the liquid portion of blood remaining after the blood cells [white blood cells (WBCs), red blood cells (RBCs), and platelets] have been removed, is most widely used in the food industry because it is neutral in taste and devoid of the dark color associated with the red blood cells (and hence whole blood) [5]. The traditional use of whole blood and its separated red blood cells as ingredients in food products is generally restricted to such products as blood sausages where the black color is both expected and acceptable [2]. The cellular portion of blood (and for that matter whole blood) has not enjoyed widespread usage in the food industry as a result of its heme component, which imparts an undesirable color, odor and metallic taste to the final product [6,7]. Even in trace quantities hemoglobin imparts a dark-brown color to foods [8]. Their use is also restricted because the cellular fraction is thought to have a higher microbial load, although this has been disproved [9]. The amount of cellular fraction-derived products used in food has traditionally been limited to 0.5 to 2% of the product in order not to jeopardize the sensory qualities of the final

Table 1. Examples of blood-derived protein ingredients used as food additives and dietary supplements

The Use of Blood and Derived Products as Food Additives 231

product [10]. This notwithstanding, recent efforts have focused on improving the utility of the cellular fraction in food proteins by removing the heme component using various techniques [6, 11-16] to produce an off-white product known in the food industry as globin or decolorized blood. Many of these treatments, however, are either not cost-effective, impart a salty or bitter taste to the globin recovered [17], or are only partially successful in alleviating the dark color associated with the heme component [8]. Thus, further processing methods continue to be devised to produce globin that lacks the bitter taste and has a whiter appearance. One such method involves treating RBCs recovered from blood with papain to release the heme, followed by further treatment with a bleaching agent, sodium

Despite the technical successes achieved, animal blood proteins remain underutilized, largely due to consumer concerns. This paper reviews some of the specific uses of blood proteins in both the meat and non-meat industries and discusses the consumer issues

The meat industry uses the bulk of the blood proteins employed as ingredients in the food industry, mainly as a binder but also as natural color enhancers, emulsifiers, fat replacers and meat curing agents. These will be discussed in turn below. However, some limited usages, for example as biodegradable natural casings for sausage products, will not be considered as such blood-based films have a relatively high solubility which may limit their

Binders have traditionally been used in meat products to counter the textural and sensorial changes brought about by processing. In addition to absorbing the moisture that is released from meat during thermal processing, they are used to bind water and fat to stabilize meat emulsions in ground meat products [19]. The development of comminuted or emulsion type meat systems that incorporate binders allows more efficient utilization of tough meat from spent animals. The partial replacement of meat with binders reduces product costs while improving, or at least maintaining, the nutritional and organoleptic qualities of the final product [20]. Binders have a macromolecular structure that has the capacity to form matrices that retain aroma and nutrients and also entrap large amounts of water in such a manner that exudation is prevented [21]. They are also used in the restructuring of meat, which is geared towards the transformation of lower value cuts and quality trimmings into consumer-ready products of higher value that resemble intact muscles such as steaks, chops or roasts. Meat restructuring is also driven by increasing consumer demand for exact

Blood plasma and isolated blood proteins are both used as binders in the meat industry. Plasma functions as a binder in meat systems due to its ability to form gels upon heating, while the performances of plasma proteins are comparable, if not superior, to other binders. In terms of binding properties, blood plasma may be an alternative to the egg albumen traditionally used in the food industry for binding purposes [22], and remains the standard by which to judge other binders. Interestingly, plasma powders have been reported to be

hypochlorite. The isolated globin is almost tasteless with a white color [17].

hindering its maximal utilization.

portions in commercial meat and fish products.

**2. Meat industry**

application [18].

**2.1 Binder**

product [10]. This notwithstanding, recent efforts have focused on improving the utility of the cellular fraction in food proteins by removing the heme component using various techniques [6, 11-16] to produce an off-white product known in the food industry as globin or decolorized blood. Many of these treatments, however, are either not cost-effective, impart a salty or bitter taste to the globin recovered [17], or are only partially successful in alleviating the dark color associated with the heme component [8]. Thus, further processing methods continue to be devised to produce globin that lacks the bitter taste and has a whiter appearance. One such method involves treating RBCs recovered from blood with papain to release the heme, followed by further treatment with a bleaching agent, sodium hypochlorite. The isolated globin is almost tasteless with a white color [17].

Despite the technical successes achieved, animal blood proteins remain underutilized, largely due to consumer concerns. This paper reviews some of the specific uses of blood proteins in both the meat and non-meat industries and discusses the consumer issues hindering its maximal utilization.

#### **2. Meat industry**

230 Food Additive

Product Company Source of blood Description Usage Fibrimex® Sonac BV, Netherlands Porcine or bovine Thrombin and fibrinogen protein isolate Cold set binder for meat products Plasma Powder FG Sonac BV, Netherlands Porcine or bovine Plasma with increased fibrinogen concentration Cold set binder for meat products Harimix (C, P or P+) Sonac BV, Netherlands Porcine or bovine Stabilized hemoglobin Coloring for meat products Hemoglobin Sonac BV, Netherlands Porcine or bovine Frozen or powder hemoglobin Natural coloring for meat products PP Sonac BV, Netherlands Porcine or bovine Frozen or powder plasma Heat set binder for meat products Prolican 70 Lican Functional Protein Source, Chile Bovine Spray-dried bovine plasma concentrate Emulsifier, gelling and binding agent in meat-based products, fish-based products, pasta and bakery products Prietin Lican Functional Protein Source, Chile Porcine Spray-dried porcine whole blood Emulsifier, gelling, binding and coloring agent in blood sausages, cured meats and pates Myored Lican Functional Protein Source, Chile Porcine or bovine Natural colorant obtained from the red pigments of blood Enhance meat color and increase contrast between fat and meat ImmunoLin® Proliant, USA Bovine Bovine serum concentrate Immune system supplement B7301 Proliant, USA Bovine Spray-dried bovine red blood cells Enhance color and iron supplementation for meat products AproRed Proliant, USA Porcine Stabilized hemoglobin Coloring for meat products Aprofer 1000® APC Europe, Spain Porcine or bovine Heme iron polypeptide Iron supplementation Proferrin® Colorado Biolabs Inc., USA Bovine Heme iron polypeptide Iron supplementation Vepro 95 HV Veos NV, Belgium Bovine

Table 1. Examples of blood-derived protein ingredients used as food additives and dietary

supplements

Globin (hemoglobin with the heme group removed) Emulsifier in meat products Plasma Veos NV, Belgium Bovine or porcine Liquid, powder, frozen or flaked plasma Gelling and binding agent in meat products

The meat industry uses the bulk of the blood proteins employed as ingredients in the food industry, mainly as a binder but also as natural color enhancers, emulsifiers, fat replacers and meat curing agents. These will be discussed in turn below. However, some limited usages, for example as biodegradable natural casings for sausage products, will not be considered as such blood-based films have a relatively high solubility which may limit their application [18].

#### **2.1 Binder**

Binders have traditionally been used in meat products to counter the textural and sensorial changes brought about by processing. In addition to absorbing the moisture that is released from meat during thermal processing, they are used to bind water and fat to stabilize meat emulsions in ground meat products [19]. The development of comminuted or emulsion type meat systems that incorporate binders allows more efficient utilization of tough meat from spent animals. The partial replacement of meat with binders reduces product costs while improving, or at least maintaining, the nutritional and organoleptic qualities of the final product [20]. Binders have a macromolecular structure that has the capacity to form matrices that retain aroma and nutrients and also entrap large amounts of water in such a manner that exudation is prevented [21]. They are also used in the restructuring of meat, which is geared towards the transformation of lower value cuts and quality trimmings into consumer-ready products of higher value that resemble intact muscles such as steaks, chops or roasts. Meat restructuring is also driven by increasing consumer demand for exact portions in commercial meat and fish products.

Blood plasma and isolated blood proteins are both used as binders in the meat industry. Plasma functions as a binder in meat systems due to its ability to form gels upon heating, while the performances of plasma proteins are comparable, if not superior, to other binders. In terms of binding properties, blood plasma may be an alternative to the egg albumen traditionally used in the food industry for binding purposes [22], and remains the standard by which to judge other binders. Interestingly, plasma powders have been reported to be

results.

**2.2 Natural color enhancer**

The Use of Blood and Derived Products as Food Additives 233

reformulated with alginate [35]. In this study, whereas some of the sensory panelists scored alginate formulated meat samples as bland or lacking uniformity in texture, no such unfavorable comments were made regarding the ActivaTM and FibrimexTM samples. Nevertheless, all three binders were rated as producing satisfactory binding in re-formed steaks and having overall acceptability [35]. These perceived differences may arise as a result of differences in the experimental procedure, for example the type of muscle used and the amount and proportion of binder used. More research is needed to identify the optimum amount of plasma proteins to utilize in particular meat products to achieve the desired

Color is known to be one of the main factors used by consumers when evaluating the quality and freshness of meat products. The trend towards natural colorants due to adverse reactions to some artificial food dyes (and their impurities) [36, 37] has resulted in the substitution of artificial colorants with natural ones where technologically feasible. Although there are many safe natural sources of colorants, their suitability for use in foodstuffs depends largely on the availability of the raw material. In this sense, hemoglobin, which is obtained from slaughtered animals, represents a good source of natural red colorant given the large quantities of blood generated daily. It is important to note that the use of hemoglobin as a colorant has the added benefit of combating iron deficiency, which will be discussed in detail in a later section of this paper. However, its red color is unstable and largely dependent on the oxidation state of the heme iron. Oxyhemoglobin, the dioxygen ferrous form is bright red in color but when the heme iron is oxidized to Fe3+ the resulting hemoprotein, known as methemoglobin (metHb), has a characteristic brown color that is undesirable. Fortunately, the concentration of metHb in mammalian red blood cells is typically only 1 to 3% of the total pigment, mainly as a result of the presence of metHb reductase [38]. However, the processing techniques utilized to preserve the shelf life and ensure the safety of the product, greatly increase the amount of metHb due to hemoglobin autooxidation [39]. Although spray-drying is a good way to preserve the red blood cell fraction, even better than freeze drying [39], and is a necessary step to ensure the microbial quality of bloodderived ingredients, oxidation of the hemoglobin may continue during the storage of the spray-dried powder. Because of the unstable nature of hemoglobin, its use as a food ingredient is only possible once it has been stabilized. Hence, hemoglobin powders that are used as food colors are treated with protecting agents that form complexes with hemoglobin, prevent oxygen accessibility to heme iron and ultimately reduce hemoglobin auto-oxidation. The following few paragraphs will look at some of the hemoglobin-stabilizing techniques

employed to make hemoglobin more useful as a natural colorant in meat products.

Chelating agents such as nicotinic acid and nicotinamide that have the ability to form complexes with the heme moiety have been reported to be effective in preventing hemoglobin auto-oxidation during drying and subsequent storage [40]. Nicotinic acid at a concentration of 2% w/v has been found to considerably retard the deterioration of hemoglobin concentrate during both spray-drying and subsequent storage. A positive effect was also detected with 2.5% w/v of nicotinamide, though the results were not as impressive as for nicotinic acid. However, in the presence of starch gels nicotinamide proved better at stabilizing the red color of hemoglobin in comparison with nicotinic acid [39]. The use of these chelating agents is not without problems. Nicotinamide, for example, has been found

less effective than egg white powder, though still better than other binders (meat powders, gelatin, wheat gluten, isolated soy protein, and a combination of sodium alginate and calcium carbonate [23]).  At acid pH, plasma produces soft and exuding gels and so is not effective as a gelling agent or capable of water retention in products with a low pH such as fermented products, as these functional properties are strongly affected by changes in the protein structure brought about by the acidic environment [24]. Subjecting porcine plasma to simultaneous treatment with microbial transglutaminase and high hydrostatic pressure has been shown to improve the gelling properties of porcine plasma under acidic conditions [25].

Besides their excellent functionality as binders, the utilization of blood proteins in the preparation of restructured meats offers a number of health and industry benefits. In the past, preparation of restructured muscle products required tumbling meat pieces with salt to extract soluble protein for meat binding. This tumbling action, however, damages the texture of the product and the use of salt is also a concern for consumers who are aware of the link between the sodium content of food and the increased risk of cardiovascular and bone disease [26, 27]. Conventionally, the process also involved the use of heat to bind the myofibrillar proteins extracted from the meat by the combined salt and tumbling action, and as such was referred to as hot-set binding [28]. The problem with the hot-set method is that the product must be sold either pre-cooked or frozen because product binding is very low in the raw state. A cold set binding agent that relies on the physiological clot forming action of the plasma proteins fibrinogen and thrombin is available commercially as Fibrimex®, and can be obtained from both bovine and porcine sources. Fibrimex® is produced through a patented process by the Dutch company Sonac BV and its binding action is based on the transformation of fibrinogen into fibrin by the action of thrombin. The fibrin produced then interacts with collagen, enabling the binding of meat pieces in reconstituted meat [29]. Fibrimex® produces restructured meat that can be sold in the chilled or raw state, with an eating quality comparable to that of cuts from intact muscles. The cold-set method utilized reduces oxidative rancidity [30] and discoloration [31], both of which are common with the hot-set method. A further advantage is that it develops sufficient bonds to eliminate the cavities [29] invariably created in the meat pieces during deboning. Products made with this cold-set binder are more versatile, as they can be treated and cooked in ways similar to fresh meat. Sonac BV also produces a cold set binder known as Plasma Powder FG, a plasma product with an increased fibrinogen concentration.

Two other commonly used cold set binders in the industry are ActivaTM TG-RM (a transglutaminase obtained from microbial sources) and alginate (a polysaccharide that works in combination with a divalent cation). Compared to ActivaTM TG-RM, Fibrimex® has been reported to produce less binding in both raw and cooked restructured pork [32]. Several studies have reported that restructured beef steaks formulated with Fibrimex® produced a weaker bind compared with alginate. However, once cooked, Fibrimex® steaks were found to have a binding strength equal or stronger than that of steaks restructured with alginate [33, 34]. Interestingly, other researchers have reported the binding strength of both raw and cooked steaks formulated with Fibrimex® to be stronger than those reformulated with alginate [35]. In this study, whereas some of the sensory panelists scored alginate formulated meat samples as bland or lacking uniformity in texture, no such unfavorable comments were made regarding the ActivaTM and FibrimexTM samples. Nevertheless, all three binders were rated as producing satisfactory binding in re-formed steaks and having overall acceptability [35]. These perceived differences may arise as a result of differences in the experimental procedure, for example the type of muscle used and the amount and proportion of binder used. More research is needed to identify the optimum amount of plasma proteins to utilize in particular meat products to achieve the desired results.

#### **2.2 Natural color enhancer**

232 Food Additive

less effective than egg white powder, though still better than other binders (meat powders, gelatin, wheat gluten, isolated soy protein, and a combination of sodium alginate and calcium carbonate [23]).  At acid pH, plasma produces soft and exuding gels and so is not effective as a gelling agent or capable of water retention in products with a low pH such as fermented products, as these functional properties are strongly affected by changes in the protein structure brought about by the acidic environment [24]. Subjecting porcine plasma to simultaneous treatment with microbial transglutaminase and high hydrostatic pressure has been shown to improve the gelling

Besides their excellent functionality as binders, the utilization of blood proteins in the preparation of restructured meats offers a number of health and industry benefits. In the past, preparation of restructured muscle products required tumbling meat pieces with salt to extract soluble protein for meat binding. This tumbling action, however, damages the texture of the product and the use of salt is also a concern for consumers who are aware of the link between the sodium content of food and the increased risk of cardiovascular and bone disease [26, 27]. Conventionally, the process also involved the use of heat to bind the myofibrillar proteins extracted from the meat by the combined salt and tumbling action, and as such was referred to as hot-set binding [28]. The problem with the hot-set method is that the product must be sold either pre-cooked or frozen because product binding is very low in the raw state. A cold set binding agent that relies on the physiological clot forming action of the plasma proteins fibrinogen and thrombin is available commercially as Fibrimex®, and can be obtained from both bovine and porcine sources. Fibrimex® is produced through a patented process by the Dutch company Sonac BV and its binding action is based on the transformation of fibrinogen into fibrin by the action of thrombin. The fibrin produced then interacts with collagen, enabling the binding of meat pieces in reconstituted meat [29]. Fibrimex® produces restructured meat that can be sold in the chilled or raw state, with an eating quality comparable to that of cuts from intact muscles. The cold-set method utilized reduces oxidative rancidity [30] and discoloration [31], both of which are common with the hot-set method. A further advantage is that it develops sufficient bonds to eliminate the cavities [29] invariably created in the meat pieces during deboning. Products made with this cold-set binder are more versatile, as they can be treated and cooked in ways similar to fresh meat. Sonac BV also produces a cold set binder known as Plasma Powder FG, a plasma

Two other commonly used cold set binders in the industry are ActivaTM TG-RM (a transglutaminase obtained from microbial sources) and alginate (a polysaccharide that works in combination with a divalent cation). Compared to ActivaTM TG-RM, Fibrimex® has been reported to produce less binding in both raw and cooked restructured pork [32]. Several studies have reported that restructured beef steaks formulated with Fibrimex® produced a weaker bind compared with alginate. However, once cooked, Fibrimex® steaks were found to have a binding strength equal or stronger than that of steaks restructured with alginate [33, 34]. Interestingly, other researchers have reported the binding strength of both raw and cooked steaks formulated with Fibrimex® to be stronger than those

properties of porcine plasma under acidic conditions [25].

product with an increased fibrinogen concentration.

Color is known to be one of the main factors used by consumers when evaluating the quality and freshness of meat products. The trend towards natural colorants due to adverse reactions to some artificial food dyes (and their impurities) [36, 37] has resulted in the substitution of artificial colorants with natural ones where technologically feasible. Although there are many safe natural sources of colorants, their suitability for use in foodstuffs depends largely on the availability of the raw material. In this sense, hemoglobin, which is obtained from slaughtered animals, represents a good source of natural red colorant given the large quantities of blood generated daily. It is important to note that the use of hemoglobin as a colorant has the added benefit of combating iron deficiency, which will be discussed in detail in a later section of this paper. However, its red color is unstable and largely dependent on the oxidation state of the heme iron. Oxyhemoglobin, the dioxygen ferrous form is bright red in color but when the heme iron is oxidized to Fe3+ the resulting hemoprotein, known as methemoglobin (metHb), has a characteristic brown color that is undesirable. Fortunately, the concentration of metHb in mammalian red blood cells is typically only 1 to 3% of the total pigment, mainly as a result of the presence of metHb reductase [38]. However, the processing techniques utilized to preserve the shelf life and ensure the safety of the product, greatly increase the amount of metHb due to hemoglobin autooxidation [39]. Although spray-drying is a good way to preserve the red blood cell fraction, even better than freeze drying [39], and is a necessary step to ensure the microbial quality of bloodderived ingredients, oxidation of the hemoglobin may continue during the storage of the spray-dried powder. Because of the unstable nature of hemoglobin, its use as a food ingredient is only possible once it has been stabilized. Hence, hemoglobin powders that are used as food colors are treated with protecting agents that form complexes with hemoglobin, prevent oxygen accessibility to heme iron and ultimately reduce hemoglobin auto-oxidation. The following few paragraphs will look at some of the hemoglobin-stabilizing techniques employed to make hemoglobin more useful as a natural colorant in meat products.

Chelating agents such as nicotinic acid and nicotinamide that have the ability to form complexes with the heme moiety have been reported to be effective in preventing hemoglobin auto-oxidation during drying and subsequent storage [40]. Nicotinic acid at a concentration of 2% w/v has been found to considerably retard the deterioration of hemoglobin concentrate during both spray-drying and subsequent storage. A positive effect was also detected with 2.5% w/v of nicotinamide, though the results were not as impressive as for nicotinic acid. However, in the presence of starch gels nicotinamide proved better at stabilizing the red color of hemoglobin in comparison with nicotinic acid [39]. The use of these chelating agents is not without problems. Nicotinamide, for example, has been found

The Use of Blood and Derived Products as Food Additives 235

casein as the emulsifying agent in meat products. Silva and others [47] compared the emulsifying properties of sodium caseinate (SC) and globin isolated either by the acidified acetone (AG) method or the carboxymethyl cellulose (CG) method in the absence and presence of salt. In the absence of salt AG and CG showed a higher emulsifying capacity (EC), which measures the ability of the emulsifier to migrate to the oil-water interface, than SC. When salt was present, however, SC showed a higher EC than globins. The emulsifying activity index (EAI), which measures the ability of the emulsifier to stay in the oil-water interface immediately after the emulsion has formed, was greatest for AG with salt present. In the absence of salt, both SC and AG exhibited EAIs that were greater than that of CG. At no and very low salt concentrations there was no difference in emulsion stability (ES) (a measure of the ability of the emulsifier to stay in the oil-water interface after storage for a while or heating of the emulsion) among all three proteins. ES was, however, greater for CA for a salt concentration of 0.25mol/L. Since the emulsifying property is a cooperative function of EC, EAI, and ES, it seems that casein as an emulsifier has an edge over globin in high salt products. This would, however, not be an advantage in the food industry, which is tending to minimize the use of salt in its products because of the problems associated with

Globin also compares favorably to other proteins used as emulsifiers in meat products and food products in general. Crenwelge and others [48] compared the emulsifying capacities of globin with those of cotton seed, soy and milk proteins and reported that globin had the best emulsifying capacity. The emulsifying activity of globin was greater (EAI of 28) than that of either hemoglobin or ovalbumin, with EAI values of 14 and 8, respectively. Other authors have also reported globin to have emulsifying activity superior to that of hemoglobin and ovalbumin, although BSA, which had an EAI value of 31, was higher. A combination of peptic hydrolysis and the addition of carboxymethyl cellulose (CMC) to globin successfully raised the emulsifying activity of globin to above that of bovine serum albumin (BSA) [49]. All the blood proteins (globin, BSA, hemoglobin) have been shown to be better emulsifiers than egg (ovalbumin), which is generally considered to have good emulsifying properties. However, plasma is reported to have better emulsifying capacity than globin when incorporated into sausages and it can be incorporated into meat products at higher inclusion levels than globin without jeopardizing the visual appeal of the product because the

decolorized product retains a reddish hue that is transferred to the final product [50].

its emulsifying capacity are likely to be the best option.

**2.4 Fat replacer**

In summary, blood proteins have excellent emulsifying capacity and can adequately replace casein and egg in emulsified meat systems. Blood proteins such as hemoglobin, when used as emulsifiers, have the added advantage of providing a good source of heme iron. Compared to casein and egg, both of which are potent allergens and are thus among the "big eight" allergens covered under the Food Allergen Labeling and Consumer Protection Act (FALCPA) law, blood proteins do not present a problem of inducing allergic reactions. In situations involving highly salted products, however, plasma or globin that has undergone further processing such as a combination of peptic hydrolysis and CMC addition to enhance

Fat plays an essential role in the diet as a source of vitamins, essential fatty acids and energy [51]. Besides its nutritional role, fat has a major effect on the tenderness, mouth feel, binding

high salt consumption mentioned above.

to be a harmful vasodilator [41]. Conversion of hemoglobin into the more stable and organoleptically acceptable carboxyhemoglobin by saturation with carbon monoxide (CO) has been proposed as an alternative method to stabilize hemoglobin. The underlying principle of the technique is based on the strong affinity between CO and hemoglobin [42] and the low dissociation of the complex [43] that provides a strong and enduring linkage of the CO to hemoglobin, which can thus tolerate cooking and/or dehydration. In addition, CO-treated blood has a redder color and hence greater potential for use in meat product formulations [44]. Studies have shown that CO-treated porcine spray-dried blood stored in low oxygen transmission rate (OTR) bags retained an acceptable reddish color after 12 weeks of storage compared to untreated dry blood, which turned brown immediately upon drying. Comparatively, CO-treated porcine spray-dried blood in high oxygen transmission rate (OTR) packaging presented color indices similar to those of untreated blood after 12 weeks of storage. The authors explained that the observed difference could be as a result of the oxygen permeability of the high OTR bags and light oxidation, which caused the otherwise stable carboxyhemoglobin to turn brown [45]. Liquid porcine blood treated with CO at different pH levels (7.4, 6.7, and 6.0) and kept under refrigeration for 4 days maintained a more stable and attractive red color than fresh blood. The study was restricted to 4 days of refrigerated storage as this is the typical period for which the bacterial count remains acceptably low and hence the blood maintains a safe microbiological profile, allowing its safe utilization as a food ingredient [44]. There are currently several such hemoglobin-containing products available for use as natural color enhancers in meat products. However, effective stabilizing methods for hemoglobin remain an issue. It is possible that shifting the focus to the development of better packaging technology may avoid the need to use stabilizing agents, resulting in the production of hemoglobin-based colorants that are both safe and more natural.

#### **2.3 Emulsifier**

Emulsifiers are utilized in emulsified meat products such as frankfurters, pate, luncheon meat and mortadella to bind meat proteins, fat and water in a stable emulsion. Emulsifiers also help redistribute the fat finely throughout the product so the right texture is obtained. Emulsifiers often substitute for fat in association with other ingredients in lowfat meat products to give the final product sensory qualities comparable to those of their full-fat versions. The food industry has access to a wide range of emulsifiers suitable for use in foods and, in particular, meat products though these tend to be proteins. Proteins are the most common emulsifying agents in the food industry because they occur naturally and are generally both non-toxic and widely available [46]. Proteins that are used as emulsifiers are obtained from a variety of sources, both animal and plant. Processors, however, generally prefer animal proteins because they are better emulsifiers than plant proteins. Amongst the emulsifiers obtained from animal sources, casein and its salt derivatives are the most popular and are widely used in the food industry for this purpose. Less expensive protein sources with comparable emulsifying capacities are being sought to replace casein, which is expensive because of its high processing costs [47]. This is particularly important in developing countries, where milk products as casein must be imported.

Blood proteins have been found to have emulsifying properties that are comparable, and even in some situations, superior to those of casein and can therefore adequately replace

to be a harmful vasodilator [41]. Conversion of hemoglobin into the more stable and organoleptically acceptable carboxyhemoglobin by saturation with carbon monoxide (CO) has been proposed as an alternative method to stabilize hemoglobin. The underlying principle of the technique is based on the strong affinity between CO and hemoglobin [42] and the low dissociation of the complex [43] that provides a strong and enduring linkage of the CO to hemoglobin, which can thus tolerate cooking and/or dehydration. In addition, CO-treated blood has a redder color and hence greater potential for use in meat product formulations [44]. Studies have shown that CO-treated porcine spray-dried blood stored in low oxygen transmission rate (OTR) bags retained an acceptable reddish color after 12 weeks of storage compared to untreated dry blood, which turned brown immediately upon drying. Comparatively, CO-treated porcine spray-dried blood in high oxygen transmission rate (OTR) packaging presented color indices similar to those of untreated blood after 12 weeks of storage. The authors explained that the observed difference could be as a result of the oxygen permeability of the high OTR bags and light oxidation, which caused the otherwise stable carboxyhemoglobin to turn brown [45]. Liquid porcine blood treated with CO at different pH levels (7.4, 6.7, and 6.0) and kept under refrigeration for 4 days maintained a more stable and attractive red color than fresh blood. The study was restricted to 4 days of refrigerated storage as this is the typical period for which the bacterial count remains acceptably low and hence the blood maintains a safe microbiological profile, allowing its safe utilization as a food ingredient [44]. There are currently several such hemoglobin-containing products available for use as natural color enhancers in meat products. However, effective stabilizing methods for hemoglobin remain an issue. It is possible that shifting the focus to the development of better packaging technology may avoid the need to use stabilizing agents, resulting in the production of hemoglobin-based

Emulsifiers are utilized in emulsified meat products such as frankfurters, pate, luncheon meat and mortadella to bind meat proteins, fat and water in a stable emulsion. Emulsifiers also help redistribute the fat finely throughout the product so the right texture is obtained. Emulsifiers often substitute for fat in association with other ingredients in lowfat meat products to give the final product sensory qualities comparable to those of their full-fat versions. The food industry has access to a wide range of emulsifiers suitable for use in foods and, in particular, meat products though these tend to be proteins. Proteins are the most common emulsifying agents in the food industry because they occur naturally and are generally both non-toxic and widely available [46]. Proteins that are used as emulsifiers are obtained from a variety of sources, both animal and plant. Processors, however, generally prefer animal proteins because they are better emulsifiers than plant proteins. Amongst the emulsifiers obtained from animal sources, casein and its salt derivatives are the most popular and are widely used in the food industry for this purpose. Less expensive protein sources with comparable emulsifying capacities are being sought to replace casein, which is expensive because of its high processing costs [47]. This is particularly important in developing countries, where milk products as casein must be

Blood proteins have been found to have emulsifying properties that are comparable, and even in some situations, superior to those of casein and can therefore adequately replace

colorants that are both safe and more natural.

**2.3 Emulsifier**

imported.

casein as the emulsifying agent in meat products. Silva and others [47] compared the emulsifying properties of sodium caseinate (SC) and globin isolated either by the acidified acetone (AG) method or the carboxymethyl cellulose (CG) method in the absence and presence of salt. In the absence of salt AG and CG showed a higher emulsifying capacity (EC), which measures the ability of the emulsifier to migrate to the oil-water interface, than SC. When salt was present, however, SC showed a higher EC than globins. The emulsifying activity index (EAI), which measures the ability of the emulsifier to stay in the oil-water interface immediately after the emulsion has formed, was greatest for AG with salt present. In the absence of salt, both SC and AG exhibited EAIs that were greater than that of CG. At no and very low salt concentrations there was no difference in emulsion stability (ES) (a measure of the ability of the emulsifier to stay in the oil-water interface after storage for a while or heating of the emulsion) among all three proteins. ES was, however, greater for CA for a salt concentration of 0.25mol/L. Since the emulsifying property is a cooperative function of EC, EAI, and ES, it seems that casein as an emulsifier has an edge over globin in high salt products. This would, however, not be an advantage in the food industry, which is tending to minimize the use of salt in its products because of the problems associated with high salt consumption mentioned above.

Globin also compares favorably to other proteins used as emulsifiers in meat products and food products in general. Crenwelge and others [48] compared the emulsifying capacities of globin with those of cotton seed, soy and milk proteins and reported that globin had the best emulsifying capacity. The emulsifying activity of globin was greater (EAI of 28) than that of either hemoglobin or ovalbumin, with EAI values of 14 and 8, respectively. Other authors have also reported globin to have emulsifying activity superior to that of hemoglobin and ovalbumin, although BSA, which had an EAI value of 31, was higher. A combination of peptic hydrolysis and the addition of carboxymethyl cellulose (CMC) to globin successfully raised the emulsifying activity of globin to above that of bovine serum albumin (BSA) [49]. All the blood proteins (globin, BSA, hemoglobin) have been shown to be better emulsifiers than egg (ovalbumin), which is generally considered to have good emulsifying properties. However, plasma is reported to have better emulsifying capacity than globin when incorporated into sausages and it can be incorporated into meat products at higher inclusion levels than globin without jeopardizing the visual appeal of the product because the decolorized product retains a reddish hue that is transferred to the final product [50].

In summary, blood proteins have excellent emulsifying capacity and can adequately replace casein and egg in emulsified meat systems. Blood proteins such as hemoglobin, when used as emulsifiers, have the added advantage of providing a good source of heme iron. Compared to casein and egg, both of which are potent allergens and are thus among the "big eight" allergens covered under the Food Allergen Labeling and Consumer Protection Act (FALCPA) law, blood proteins do not present a problem of inducing allergic reactions. In situations involving highly salted products, however, plasma or globin that has undergone further processing such as a combination of peptic hydrolysis and CMC addition to enhance its emulsifying capacity are likely to be the best option.

#### **2.4 Fat replacer**

Fat plays an essential role in the diet as a source of vitamins, essential fatty acids and energy [51].  Similarly, the WHC of beef burgers containing Plasma Powder U70 and Protoplus70 were

Blood proteins therefore provide a cheaper alternative protein for use as fat replacers in the production of low-fat meat products. However, this may not satisfy some consumers due to the non-meaty flavor resulting from their inclusion. Guzman and others [59] have attributed the lower meaty scores when blood proteins are incorporated to the specific flavor characteristics contributed by each type of blood protein. Since a single ingredient is unlikely to produce the desired effect as a fat-replacer in the production of low-fat meat products [57], combining plasma proteins with other fat replacers with superior meaty

Nitrite plays a multifunctional role in the curing process of meat. It is responsible for the red color [60, 61], and characteristics and desirable flavor of cured meats [62, 63]. It may also influence the texture of the product through the promotion of protein cross-linking [64]. Furthermore, nitrite acts as an antimicrobial agent [65, 66]. Although nitrite continues to be the most widely used of all food additives, its use has come under scrutiny in recent years. This is because nitrite has a tendency to react with amines, amides, amino acids and related compounds present in the meat to produce carcinogenic N-nitroso compounds. In addition, ingested nitrite (in the form of residual nitrite) may react with various substances in the gastrointestinal tract (GIT) to produce these N-nitroso compounds [67, 68]. Various studies have confirmed the presence of volatile N-nitrosamines in cured meat compounds, though there are differences in both the type and the quantities reported by different authors [69]. To address these issues, efforts are being made to reduce the amount of nitrite used in the curing system or to develop alternative methods of curing that avoid the use of nitrite altogether. The latter approach may be the best option; the most attractive and reliable method for preventing the formation of N-nitroso compounds is the total elimination of nitrite from the curing process [70]. However, finding a viable alternative for nitrite in the meat curing process is problematic as it is extremely difficult to find a single compound that can fully reproduce the multifunctional role of nitrite described above. To date, no single agent has been identified that is capable of replacing nitrite. The best option may be the use of a composite mixture containing no nitrite but instead comprising a colorant, an antioxidant,

and an antimicrobial agent, among others, to produce nitrite-free cured meats [71].

One of the colorants suggested for use in a composite nitrite-free cocktail for meat curing is cooked cured meat pigment (CCMP), which when added to meat prior to cooking duplicates the color typical of nitrite-cured meats. CCMP, a mono and/or di-nitric oxide hemochrome, is synthesized directly or indirectly through a hemin intermediate. The pigment is prepared by reacting bovine or porcine red blood cells with a nitrosating agent and at least one reducing agent at a suitable elevated temperature. The resultant product is either spray-dried or freeze-dried to obtain a powder. The pigment may also be treated with a starch and a binding agent (e.g. gum) to stabilize the pigment [72]. Addition of CCMP to comminuted pork meat at levels of 3 to 30mg/kg produced a pink color after heat-treatment that was visually similar to that of nitrite-treated pork [73]. Although the best performance of CCMP is in meat systems containing low to intermediate concentrations of myoglobin, its

superior to 15 and 12 other fat replacers, respectively.

flavor characteristics promises to be a worthwhile approach.

**2.5 Curing agent**

properties, juiciness and overall appearance and palatability of processed meats [52]. On the other hand, empirical data has shown a correlation between dietary fat and cardio-vascular disease (CVD) and some types of cancers (colon, breast and prostate). Thus, for today's health conscious consumers, reducing dietary fat is a major consideration. The meat industry has been seriously affected by adverse publicity due to the high fat content and unhealthy fatty acid composition of their products, particularly those that include emulsified meat. For example, the minimum fat content in finely ground meat emulsion type products such as frankfurters, dry fermented sausages, and spreadable dry sausages are about 10%, 20-30%, and 20%, respectively [53] and this includes considerable amounts of saturated fatty acids. In response to consumer demand, the food industry has developed an assortment of low-fat meat products but given the important physico-chemical and sensory role that is played by fat, replacing fat in food products is a daunting task: if not properly done, the sensory appeal of the product will be severely jeopardized. Thus, low-fat meat varieties that are not acceptable in terms of taste and appearance will simply not sell, regardless of any health benefits [54].

Studies have shown blood proteins to have potential as fat replacers in meat products, contributing soluble proteins while at the same time reducing costs. They also reduce the caloric content of food for every gram of fat replaced, since proteins contain fewer calories than fat. In addition blood proteins are a natural product and hence in line with present day consumer demands for natural foodstuffs. In a study by Viana and others [55], replacing the fat with globin, plasma, and a combination of plasma and globin resulted in ham pates with 25%, 35% and 35% less fat, respectively. Among the treatments, the reduction in fat observed was not statistically different. The use of these fat replacers also resulted in an increase in moisture and protein content with no observed change in aroma, taste and consistency. The color of pate was, however, reduced in all the treatments containing blood proteins in comparison with control samples with no added blood protein.  In short, fat influences the color of meat products and reducing its level will invariably affect the color attributes of the product.

The use of blood proteins as fat replacers compared favorably with other commercially available fat replacers, as shown by the results of several studies. Confrades and others [57] compared the effect of plasma and soy fiber as fat replacers in bologna sausage, concluding that plasma protein had a greater influence on the binding and textural properties of bologna than soy fiber and was hence a better choice. Desmond and others [58] evaluated the sensory, chemical and physical properties of low-fat beef burgers formulated with nineteen different commercially available fat replacers including Plasma Powder U70 and Protoplus® U70, both of which are blood-derived products. They reported that beef burgers formulated with these blood proteins had poor overall quality and flavor attributes. It is worth noting, however, that burgers containing these blood proteins had individual sensory traits that were superior to burgers containing other fat replacers. For example, the moistness and juiciness of burgers formulated with Protoplus® U70 was superior to 15 of the 17 non-blood derived fat replacers tested. Burgers containing Protoplus® U70 were rated as having the best overall texture, together with three other non-blood fat replacers. Inclusion of these blood proteins also produced physical characteristics that were superior to most of the other fat replacers used.  Similarly, the WHC of beef burgers containing Plasma Powder U70 and Protoplus70 were superior to 15 and 12 other fat replacers, respectively.

Blood proteins therefore provide a cheaper alternative protein for use as fat replacers in the production of low-fat meat products. However, this may not satisfy some consumers due to the non-meaty flavor resulting from their inclusion. Guzman and others [59] have attributed the lower meaty scores when blood proteins are incorporated to the specific flavor characteristics contributed by each type of blood protein. Since a single ingredient is unlikely to produce the desired effect as a fat-replacer in the production of low-fat meat products [57], combining plasma proteins with other fat replacers with superior meaty flavor characteristics promises to be a worthwhile approach.

#### **2.5 Curing agent**

236 Food Additive

properties, juiciness and overall appearance and palatability of processed meats [52]. On the other hand, empirical data has shown a correlation between dietary fat and cardio-vascular disease (CVD) and some types of cancers (colon, breast and prostate). Thus, for today's health conscious consumers, reducing dietary fat is a major consideration. The meat industry has been seriously affected by adverse publicity due to the high fat content and unhealthy fatty acid composition of their products, particularly those that include emulsified meat. For example, the minimum fat content in finely ground meat emulsion type products such as frankfurters, dry fermented sausages, and spreadable dry sausages are about 10%, 20-30%, and 20%, respectively [53] and this includes considerable amounts of saturated fatty acids. In response to consumer demand, the food industry has developed an assortment of low-fat meat products but given the important physico-chemical and sensory role that is played by fat, replacing fat in food products is a daunting task: if not properly done, the sensory appeal of the product will be severely jeopardized. Thus, low-fat meat varieties that are not acceptable in terms of taste and appearance will simply not sell,

Studies have shown blood proteins to have potential as fat replacers in meat products, contributing soluble proteins while at the same time reducing costs. They also reduce the caloric content of food for every gram of fat replaced, since proteins contain fewer calories than fat. In addition blood proteins are a natural product and hence in line with present day consumer demands for natural foodstuffs. In a study by Viana and others [55], replacing the fat with globin, plasma, and a combination of plasma and globin resulted in ham pates with 25%, 35% and 35% less fat, respectively. Among the treatments, the reduction in fat observed was not statistically different. The use of these fat replacers also resulted in an increase in moisture and protein content with no observed change in aroma, taste and consistency. The color of pate was, however, reduced in all the treatments containing blood proteins in comparison with control samples with no added blood protein.  In short, fat influences the color of meat products and reducing its

The use of blood proteins as fat replacers compared favorably with other commercially available fat replacers, as shown by the results of several studies. Confrades and others [57] compared the effect of plasma and soy fiber as fat replacers in bologna sausage, concluding that plasma protein had a greater influence on the binding and textural properties of bologna than soy fiber and was hence a better choice. Desmond and others [58] evaluated the sensory, chemical and physical properties of low-fat beef burgers formulated with nineteen different commercially available fat replacers including Plasma Powder U70 and Protoplus® U70, both of which are blood-derived products. They reported that beef burgers formulated with these blood proteins had poor overall quality and flavor attributes. It is worth noting, however, that burgers containing these blood proteins had individual sensory traits that were superior to burgers containing other fat replacers. For example, the moistness and juiciness of burgers formulated with Protoplus® U70 was superior to 15 of the 17 non-blood derived fat replacers tested. Burgers containing Protoplus® U70 were rated as having the best overall texture, together with three other non-blood fat replacers. Inclusion of these blood proteins also produced physical characteristics that were superior to most of the other fat replacers used. For example, beef burger containing these blood

regardless of any health benefits [54].

level will invariably affect the color attributes of the product.

Nitrite plays a multifunctional role in the curing process of meat. It is responsible for the red color [60, 61], and characteristics and desirable flavor of cured meats [62, 63]. It may also influence the texture of the product through the promotion of protein cross-linking [64]. Furthermore, nitrite acts as an antimicrobial agent [65, 66]. Although nitrite continues to be the most widely used of all food additives, its use has come under scrutiny in recent years. This is because nitrite has a tendency to react with amines, amides, amino acids and related compounds present in the meat to produce carcinogenic N-nitroso compounds. In addition, ingested nitrite (in the form of residual nitrite) may react with various substances in the gastrointestinal tract (GIT) to produce these N-nitroso compounds [67, 68]. Various studies have confirmed the presence of volatile N-nitrosamines in cured meat compounds, though there are differences in both the type and the quantities reported by different authors [69]. To address these issues, efforts are being made to reduce the amount of nitrite used in the curing system or to develop alternative methods of curing that avoid the use of nitrite altogether. The latter approach may be the best option; the most attractive and reliable method for preventing the formation of N-nitroso compounds is the total elimination of nitrite from the curing process [70]. However, finding a viable alternative for nitrite in the meat curing process is problematic as it is extremely difficult to find a single compound that can fully reproduce the multifunctional role of nitrite described above. To date, no single agent has been identified that is capable of replacing nitrite. The best option may be the use of a composite mixture containing no nitrite but instead comprising a colorant, an antioxidant, and an antimicrobial agent, among others, to produce nitrite-free cured meats [71].

One of the colorants suggested for use in a composite nitrite-free cocktail for meat curing is cooked cured meat pigment (CCMP), which when added to meat prior to cooking duplicates the color typical of nitrite-cured meats. CCMP, a mono and/or di-nitric oxide hemochrome, is synthesized directly or indirectly through a hemin intermediate. The pigment is prepared by reacting bovine or porcine red blood cells with a nitrosating agent and at least one reducing agent at a suitable elevated temperature. The resultant product is either spray-dried or freeze-dried to obtain a powder. The pigment may also be treated with a starch and a binding agent (e.g. gum) to stabilize the pigment [72]. Addition of CCMP to comminuted pork meat at levels of 3 to 30mg/kg produced a pink color after heat-treatment that was visually similar to that of nitrite-treated pork [73]. Although the best performance of CCMP is in meat systems containing low to intermediate concentrations of myoglobin, its

The Use of Blood and Derived Products as Food Additives 239

enzymatically hydrolyzed plasma and 10% beef stock as a replacement for eggs in the formulation of devil's food cake, a whole-egg product. The results are not relevant here, however, due to the inclusion of beef stock which makes it difficult to deduce which product effects can be ascribed to the inclusion of plasma only. In a similar study, Johnson and others [77] investigated the feasibility of replacing egg white and whole egg with freezedried plasma in the manufacture of white and yellow layer cakes, respectively. In the latter case, 1.3% lecithin was added to compensate for the natural phospholipid content of whole egg. The control cakes consisted of 14% egg white solids and 3% added salt, whereas the experimental cakes contained 18.6% plasma solids with no added salt. The formulation was selected to ensure equivalent protein and salt concentrations for the plasma and egg-white control cakes. The authors reported that cakes made with plasma were at least equal if not greater in volume and also shrank less than the egg-white control cakes. In the case of the yellow layer cakes, the volumes of those made with plasma solids was between 7 and 15% less than those made with whole egg at equivalent protein levels. They concluded that blood plasma was effective in replacing all the egg white or whole egg in cakes and hence shows

Decolorized bovine blood has also been considered as a replacement for egg white in white layer cakes. Although cakes made with decolorized blood had volumes comparable to those made with egg white, cakes made with decolorized blood had an objectionable flavor [78]. The poor sensory quality of cakes formulated with decolorized blood may be due to residual heme. Raeker and Johnson [79] also compared the baking properties of egg white and plasma and their component proteins, reporting that cakes made with egg whites had slightly greater volumes than their counterparts made with freeze or spray-dried plasma, though the differences were not significant. Among the blood proteins, only γ-globulin had baking properties superior to those of plasma. They also noted that separating fibrinogen (which by itself produced the smallest cake volume among the blood plasma proteins) from plasma increased cake volumes. However, given that the primary purpose of using blood proteins as a substitute for eggs in baked goods is to reduce costs, the additional expense incurred by fractionating plasma into its component proteins appears counterproductive and there appears to be no incentive for using fractionated plasma proteins for this purpose. In summary, plasma proteins can be very effective low cost alternatives for replacing eggs in baked goods. The use of blood proteins derived from the cellular fraction, as decolorized bovine blood leads to the production of baked goods with objectionable odor, however, and further research is needed to counter the flavor defect associated with its use. Also, since the main objective of replacing eggs with plasma is to reduce cost, the use of expensive fractionated blood proteins for this purpose cannot be justified. The removal of fibrinogen from plasma, leading to an increase in cake volumes, may be a practicable means of improving the efficiency of plasma for this purpose, as separation of this component from

Protein malnutrition is a major problem in developing countries during the transitional phase of weaning in infants, retarding their physical and mental development. Introducing weaning foods containing the right quality and quantity of protein during this transitional period has been recommended by international bodies such as the WHO and FAO as a

potential as a low cost egg substitute for use by the baking industry.

plasma by centrifugation would be relatively inexpensive.

**3.2 Protein supplement**

performance in dark meats has been found to be satisfactory [71]. Results support CCMP as a healthy substitute for nitrite salt, as CCMP has been found not to be mutagenic compared to nitrite. The use of CCMP in meat emulsions therefore results in a drastic reduction in the residual nitrite that contributes to the formation of carcinogenic N-nitroso compounds in the GIT [69].

Though CCMP was initially developed for use in cured meat products to duplicate the characteristic red color associated with the use of nitrite, it has also been found to have antioxidant properties similar to those of nitrite [74]. At the time of writing, CCMP is not yet available commercially, possibly due to its unstable nature although this is being improved with the use of stabilizers. Further studies to include the addition of antimicrobials in the formulation of CCMP to duplicate all three major functions of nitrite in cured meats may make possible the commercialization of this product in the near future.

#### **3. Non-meat usage**

Although the meat industry remains the predominant user of blood proteins, other sectors of the food industry also utilize them in the production of such items as baked goods, dietary supplements and functional foods, usually as egg replacers, protein supplements, iron supplements or a source of bioactive compounds. Some of these uses will be reviewed in this section.

#### **3.1 Egg replacer**

In baked goods such as cakes, egg proteins play an important role in defining such final product characteristics as cake volume and texture due to the unique foaming, emulsifying, and heat coagulation properties of eggs [75]. Among the various ingredients utilized in baked goods, eggs are the most costly [76] and they are also a significant source of cholesterol. The use of alternative ingredients to partially or totally replace eggs in baked goods is therefore of interest to processors not only to reduce cost but to provide lower cholesterol baked goods varieties. Blood proteins have been found to serve as useful egg replacers, as reported by several authors. Spray-dried plasma protein concentrates marketed for diverse use in food processing, including as egg replacers, are sold at a cost of only about one-third that of spray-dried egg whites [76].

Lee and others [76] evaluated the sensory and physical properties of white layer cakes made by substituting egg (as dried egg white) either partially (25%, 50% and 70%) or totally (100%) with spray-dried plasma. The authors reported that cake volume was not affected by egg replacement, although cake symmetry decreased at 75% and 100% substitution. In terms of shrinkage, cakes formulated using partial replacement had lower shinkage values than control cakes made entirely with dried egg white; those formulated with total replacement of egg with plasma produced shrinkage that did not differ significantly from the control cakes. This suggests that so far as critical quality indices such as volume and shrinkage are involved, replacing egg with plasma produced superior products, particularly at partial replacement. It is worth noting that the authors reported that replacing egg with plasma at all levels resulted in products with darker and tanner crust and crumb, but these differences notwithstanding, trained panels liked the control cakes and those prepared with partial or total replacement of egg with plasma equally. The same study [76] utilized a blend of 90%

performance in dark meats has been found to be satisfactory [71]. Results support CCMP as a healthy substitute for nitrite salt, as CCMP has been found not to be mutagenic compared to nitrite. The use of CCMP in meat emulsions therefore results in a drastic reduction in the residual nitrite that contributes to the formation of carcinogenic N-nitroso compounds in the

Though CCMP was initially developed for use in cured meat products to duplicate the characteristic red color associated with the use of nitrite, it has also been found to have antioxidant properties similar to those of nitrite [74]. At the time of writing, CCMP is not yet available commercially, possibly due to its unstable nature although this is being improved with the use of stabilizers. Further studies to include the addition of antimicrobials in the formulation of CCMP to duplicate all three major functions of nitrite in cured meats may

Although the meat industry remains the predominant user of blood proteins, other sectors of the food industry also utilize them in the production of such items as baked goods, dietary supplements and functional foods, usually as egg replacers, protein supplements, iron supplements or a source of bioactive compounds. Some of these uses will be reviewed

In baked goods such as cakes, egg proteins play an important role in defining such final product characteristics as cake volume and texture due to the unique foaming, emulsifying, and heat coagulation properties of eggs [75]. Among the various ingredients utilized in baked goods, eggs are the most costly [76] and they are also a significant source of cholesterol. The use of alternative ingredients to partially or totally replace eggs in baked goods is therefore of interest to processors not only to reduce cost but to provide lower cholesterol baked goods varieties. Blood proteins have been found to serve as useful egg replacers, as reported by several authors. Spray-dried plasma protein concentrates marketed for diverse use in food processing, including as egg replacers, are sold at a cost of only about

Lee and others [76] evaluated the sensory and physical properties of white layer cakes made by substituting egg (as dried egg white) either partially (25%, 50% and 70%) or totally (100%) with spray-dried plasma. The authors reported that cake volume was not affected by egg replacement, although cake symmetry decreased at 75% and 100% substitution. In terms of shrinkage, cakes formulated using partial replacement had lower shinkage values than control cakes made entirely with dried egg white; those formulated with total replacement of egg with plasma produced shrinkage that did not differ significantly from the control cakes. This suggests that so far as critical quality indices such as volume and shrinkage are involved, replacing egg with plasma produced superior products, particularly at partial replacement. It is worth noting that the authors reported that replacing egg with plasma at all levels resulted in products with darker and tanner crust and crumb, but these differences notwithstanding, trained panels liked the control cakes and those prepared with partial or total replacement of egg with plasma equally. The same study [76] utilized a blend of 90%

make possible the commercialization of this product in the near future.

GIT [69].

**3. Non-meat usage**

in this section.

**3.1 Egg replacer**

one-third that of spray-dried egg whites [76].

enzymatically hydrolyzed plasma and 10% beef stock as a replacement for eggs in the formulation of devil's food cake, a whole-egg product. The results are not relevant here, however, due to the inclusion of beef stock which makes it difficult to deduce which product effects can be ascribed to the inclusion of plasma only. In a similar study, Johnson and others [77] investigated the feasibility of replacing egg white and whole egg with freezedried plasma in the manufacture of white and yellow layer cakes, respectively. In the latter case, 1.3% lecithin was added to compensate for the natural phospholipid content of whole egg. The control cakes consisted of 14% egg white solids and 3% added salt, whereas the experimental cakes contained 18.6% plasma solids with no added salt. The formulation was selected to ensure equivalent protein and salt concentrations for the plasma and egg-white control cakes. The authors reported that cakes made with plasma were at least equal if not greater in volume and also shrank less than the egg-white control cakes. In the case of the yellow layer cakes, the volumes of those made with plasma solids was between 7 and 15% less than those made with whole egg at equivalent protein levels. They concluded that blood plasma was effective in replacing all the egg white or whole egg in cakes and hence shows potential as a low cost egg substitute for use by the baking industry.

Decolorized bovine blood has also been considered as a replacement for egg white in white layer cakes. Although cakes made with decolorized blood had volumes comparable to those made with egg white, cakes made with decolorized blood had an objectionable flavor [78]. The poor sensory quality of cakes formulated with decolorized blood may be due to residual heme. Raeker and Johnson [79] also compared the baking properties of egg white and plasma and their component proteins, reporting that cakes made with egg whites had slightly greater volumes than their counterparts made with freeze or spray-dried plasma, though the differences were not significant. Among the blood proteins, only γ-globulin had baking properties superior to those of plasma. They also noted that separating fibrinogen (which by itself produced the smallest cake volume among the blood plasma proteins) from plasma increased cake volumes. However, given that the primary purpose of using blood proteins as a substitute for eggs in baked goods is to reduce costs, the additional expense incurred by fractionating plasma into its component proteins appears counterproductive and there appears to be no incentive for using fractionated plasma proteins for this purpose.

In summary, plasma proteins can be very effective low cost alternatives for replacing eggs in baked goods. The use of blood proteins derived from the cellular fraction, as decolorized bovine blood leads to the production of baked goods with objectionable odor, however, and further research is needed to counter the flavor defect associated with its use. Also, since the main objective of replacing eggs with plasma is to reduce cost, the use of expensive fractionated blood proteins for this purpose cannot be justified. The removal of fibrinogen from plasma, leading to an increase in cake volumes, may be a practicable means of improving the efficiency of plasma for this purpose, as separation of this component from plasma by centrifugation would be relatively inexpensive.

#### **3.2 Protein supplement**

Protein malnutrition is a major problem in developing countries during the transitional phase of weaning in infants, retarding their physical and mental development. Introducing weaning foods containing the right quality and quantity of protein during this transitional period has been recommended by international bodies such as the WHO and FAO as a

The Use of Blood and Derived Products as Food Additives 241

that of the control group consuming whey supplements. Nonetheless, the results of this study demonstrate that blood proteins can adequately replace other animal proteins such as whey. The adequacy of blood proteins as protein supplements has also been demonstrated by Oshodi and others [92] who investigated in vitro protein digestibility (using a multienzyme digesting system comprising trypisn, chymotrypsin, and peptidase), amino acid profile and available iron of an infant weaning food prepared from maize flour and bovine blood. Their results indicated an improved digestibility when blood protein concentrate was added to the maize. The amino acid profile of the formula was also satisfactory in meeting the essential amino acid requirement for infants as specified by the FAO/WHO joint committee [80]. The iron content of the formula was double that of maize alone. In this study [92], the bovine blood powder concentrate used was so bland in taste that its addition to the maize flour did not alter the overall flavor. This contrasts with the study discussed earlier where the blends containing BSC appeared to be less liked than those containing WPC, which is understandable as the subjects were still suckling and therefore not accustomed to unusual tastes (in this case BSC; WPC is similar to milk). In a related study by Lembcke and others [93], older children (between the ages of 9 and 25 months) admitted for rehabilitation for severe cases of protein deficiency (manifested as marasmus and kwashiorkor) were fed diets in which 25% or 50% of the dietary protein normally provided by milk was substituted with an equivalent protein from spray-dried bovine serum. Here, the formulas containing the spray-dried bovine serum were well accepted by the children Also, weight gain on the test diets was no different from those on the control diet. It is important to note, however, that in this study [93] the milk fat in the spray-dried bovine serum diet was partially replaced by vegetable oil. The addition of fat, which plays a critical role in the organoleptic quality of foods, could also be responsible for the greater acceptability of the product in this case.

The studies outlined above support the use of bovine blood proteins as efficient protein supplements in cereal and grain based weaning and infant diets as a measure to tackle protein malnutrition problems in developing countries. However, if the target consumers are infants that are starting to consume solid foods, the addition of vegetable oil or other flavors may be necessary to improve the palatability and consequent acceptability of formulas. Where anemic children are involved, the use of bovine blood instead of plasma or serum offers a useful way to combat this condition owing to the heme content of blood.

Iron deficiency is the most common nutritional deficiency in the world affecting about 20% of the world's population, with women and children at greater risk [94]. It is induced in part by plant-based diets that typically contain non-heme iron, a form of iron that is poorly absorbed [95, 96]. In infants, iron deficiency can delay normal infant motor and mental function [97. 98]. Iron deficiency manifesting as anemia in pregnant women increases the risk of small or preterm babies [99], which are more likely to suffer from health problems or die in the first year of life. It can also cause fatigue in adults, impairing their ability to do physical work [100]. Several strategies are commonly directed at combating iron deficiency, including supplementation with capsules and tablets and fortification of processed foods. However, in developing countries, food-based strategies remain the most sustainable approach for addressing iron and other micronutrient deficiencies [101]. Fortifying staple foods with heme-iron, which is better absorbed than non-heme iron because its absorption is

**3.3 Iron supplement**