
 fragaria vesca l. is a well - known and valuable plant species ; however , its cultivation is still much poorly spread .
currently grown cultivars of fragaria vesca are derived from a wild species , which can be found in woods and grasslands in europe , western asia , north america , and temperate areas in chile .
their widespread temperate growing range , self - compatibility , and long history of cultivation , coupled with selection for favorable recessive traits such as day neutrality , nonrunnering , and yellow - fruited forms , offer extensive genotypic diversity . despite high price ,
wild strawberries fruits are a product that is highly appreciated by consumers . their natural aspect , color , nutritional values , and high natural antioxidant compounds content are their most attractive characteristics .
a high percentage of these fruits are sold as a frozen product , which is used in the manufacturing of cakes , ice creams , or milk desserts [ 1 , 4 ] .
there are an increasing demand for fresh berries and , consequently , a need to increase their distribution ratio and shelf life .
is unusual in what is called the fruit actually originates from the expansion of the flower base ( the receptacle ) as a pseudocarp , with the real one seeded fruits ( achenes ) on the epidermal layer [ 57 ] .
wild strawberry fruits ripen during 3 - 4 weeks after flowers develop , although the period greatly depends on the weather conditions .
many epidemiological studies have shown that a higher consumption of fruit and vegetables is associated with the prevention of chronic diseases such as diabetes , heart disease , and certain cancers . apart from essential nutrients , fruit and
vegetables also contain a variety of different phytochemicals that can act as antioxidants , prevent oxidation , and also exhibit other bioactive physiological properties .
different antioxidants , such as flavonoids , phenolic acids , carotenoids , and ascorbic acid , have been proposed to act anticarcinogenically [ 813 ] .
red , spherical , sweet taste fruits ( fragariae fructus ) with unforgettable flavor are one of the raw materials achieved from wild strawberry . according to much of the research done , wild strawberry fruits have high antioxidant activity , which has been linked to their content of phenolic compounds [ 4 , 14 ] .
small fruit breeding programs are currently used to acquire new cultivars improved for specific agronomic ( yield and size ) , qualitative ( firmness , sugars content , and acidity ) , and sensorial ( colour and aroma ) characteristics , all combined to increased disease resistance and plant adaptability . nowadays , besides all these parameters , it is necessary to look for the specific bioactive components well known for their effect on human health .
flavonoids and phenolic acids are the most common phenolic compounds in small fruits with strong antioxidant capacity [ 13 , 1618 ] . taking this into account , the following study was carried out to make chemical analyses aim at evaluating the contents of flavonoids , free phenolic acids , tannins , anthocyanins , and antioxidant activity ( % ) by means of dpph radical neutralization ability in fresh and air - dried fruits of three wild strawberry cultivars .
the aim of these studies was to identify cultivars which were characterized by the highest content of investigated biologically active substances and the highest ability to free radicals elimination .
the results from the performed experiments will also have practical application during the breeding program preparation in order to obtain new cultivars of this species .
baron von solemacher ,   yellow wonder ,  and  regina  originating from agrotechnical experiments carried out at department of vegetable and medicinal plants , university of life sciences , lublin ( poland , 5123 n , 2256 e ) .
seeds of tested cultivar were sown manually on march 5th , 2010 , into boxes filled with a substrate ( peat substrate ) and covered with thin sand layer .
after emergence and forming 2 - 3 true leaves , the seedlings were transferred into boxes at 5  3.5  cm spacing .
plants were set into their permanent place on june 20th , 2010 , in plots of 7.5  m area ( 2.0  3.75  m ) at 40  25  cm spacing ( 14 plants per row , i.e. , 9.3 plantsm ) in three replicates .
the agrotechnical experiment was carried out on dusty soil characterized by good abundance in nutrients and neutral reaction .
soil under wild strawberry cultivation was prepared according to commonly accepted recommendations applying manure ( 40  kgha ) for the forecrop ( onion ) .
phosphorus , potassium , and magnesium fertilizers were used before seedling planting at the following amounts : 80  kgha  p2o5 ; 100  kgha  k2o . starter rate ( n30  kgha ) was applied , when the seedling was taken the roots .
the fruit harvest was carried out at the full of fruiting stage in years 20112013 .
directly after the harvest , part of material was subject to laboratory analyses as raw , while another part was dried out .
the drying process was performed in a drying facility at 40c till the moment of a constant air - dried fruit weight achievement .
raw material was subject to determinations of dry matter ( % ) by means of drier method , weight loss after drying - moisture ( % )   content flavonoids ( mgg ) , sum of phenolic acids ( mgg ) , tannins ( % ) , anthocyanins ( mg100  g ) , and antioxidant capacity ( % ) as an ability to neutralize the dpph radicals .
biochemical analysis was performed in laboratory for vegetable and herbal material quality at the department of vegetable and medicinal plants , university of life sciences , lublin .
aliquots of about 1  g ( 0.0001  g accuracy ) of raw and ground fruits were weighed .
the drying process was repeated till the constant weight of samples ( difference between two subsequent weighings should not be greater than 0.5  mg ) .
the difference of weights before and after drying was the water loss , and then the result was recalculated onto the percentage of dry matter .
the loss after drying was determined by means of gravimetric method according to polish pharmacopoeia vii .
samples of 1  g of three cultivars of ground wild strawberry fruits were weighed in vessels .
samples were then placed in a drier at 105c and dried for 2 hours ; after that they were cooled to ambient temperature in desiccator over silica gel and weighed again .
the drying was repeated until the constant weight ( difference between two subsequent weighings should not be greater than 0.5  mg ) .
the difference of weights before and after drying was the water loss ( moisture content ) ; all determinations were made in 3 replicates .
total flavonoids were estimated according to the spectrophotometric method of christ and mller   after their extraction , as recommended by the european pharmacopoeia . for this purpose , 2.0  g of crushed fruit
was added to a round - bottomed flask ; 20  ml of acetone , 2  ml of hcl ( 281  gl ) , and 1  ml of methenamine ( 5  gl ) were then added and the mixture was maintained for 30  min under reflux on a water bath .
the hydrolysate was filtered through cotton wool into a volumetric flask of 100  ml , then placed in a flask together with the cotton pellet and 20  ml of acetone , and refluxed for 10  min .
next , 20  ml of solution was dispensed into a separatory funnel with 20  ml of water and extracted with ethyl acetate in 15  ml portions 3 times with 10  ml .
the combined organic layers were washed twice with 40  ml of water , filtered into a volumetric flask of 50  ml , and supplemented with ethyl acetate . to determine flavonoid content ,
2 samples were prepared : to 10  ml of the stock solution 2  ml of a solution of aluminum chloride ( 20  gl ) was added , supplemented with a mixture ( 1  :  19 ) of acetic acid ( 1.02  kgl ) and methanol ( 25  ml ) . to prepare the comparative solution ,
stock was supplemented with 10  ml of a mixture ( 1  :  19 ) of acetic acid ( 1.02  kgl ) and methanol ( 25  ml ) .
after 45  min , the absorbance of the solutions was read at  = 425  nm on hitachi u-2900 spectrophotometer using the reference solution for comparison .
the total content of flavonoids ( mgg ) was expressed as quercetin qe equivalent according to the following formula:(1)x = kam , where x are total flavonoids ( mgg ) ; a is the absorbance of the solution being studied ; k is the convection factor for quercetin and equal to 8.750 ; m is the sample with the raw material ( g ) which was the amount of fresh and dry material .
total phenolic acids estimation was carried out according to arnov method , which corresponds to the recommendations of the european pharmacopoeia . to 5.0 
g of homogenized raw material placed in a round - bottomed flask 20  ml of methanol was added and the mixture was heated for 30  min at 70c in a water bath at reflux .
the hydrolysate was filtered through a hard filter paper into an erlenmeyer flask of 100  ml .
the filtered medium was returned to the round - bottomed flask with 20  ml of methanol and heated at reflux for 30  min .
the combined filtrates were taken to the tube with 1  ml of blueberry extract , 1  ml of 0.5  n hydrochloric acid , 1  ml of arnov reagent , and 1  ml of 1  n sodium hydroxide , made up to 10  ml with distilled water .
the total phenolic acid content , expressed as acid equivalent weight of caffeic acid ( cae ) in the fruit , was calculated from the equation obtained from the calibration curve of caffeic acid ( y = 1.7321x + 0.0227 ; r2 = 0.9992 ) .
samples of raw material ( 1.0  g ) were extracted with 50  ml hcl ( 1  moldm ) and heated in water bath for 1 hour .
the obtained extract was hydrolyzed with 20  ml n - butanol , and then two portions of 10  ml n - butanol were added as a solution .
the percentage of anthocyanins , as delphinidin chloride , was calculated from the expression(2)p = avfm , where p are total anthocyanins ( mg100  g ) ; a is absorbance at 533  nm ; v is value of butanol phase ( 50  ml ) ; f is coefficient for delphinidin chloride ( 2,6 ) ; m is mass of sample to be examined ( mg ) .
antioxidant activity ( % ) was evaluated on a base of the ability to neutralize the dpph radicals by means of spectrophotometry according to chen and ho : to do this , water extracts were prepared from fruits ; extracts were then evaporated till dried and lyophilized .
the absorbance measurements were made at  = 517  nm wavelength using spectrophotometer hitachi u-2900 .
all reagents and solvents were of analytical grade chemicals from merck ( darmstadt , germany ) or sigma chemical co. ( st .
louis , mo , usa ) and poch ( gliwice , poland ) . achieved results from laboratory experiments were statistically processed by means of variance analysis method and tukey 's confidence intervals at 5% confidence level .
determinations related to the chemical composition of three wild strawberry cultivars fruits here presented were preceded with the evaluation of general physicochemical parameters , that is , dry matter content in raw fruits and weight loss after drying - moisture content in dried fruits .
data presented in table 2 indicate that dry matter content in raw fruits ranged from 27.95% to 37.73% . among compared cultivars ,  baron von solemacher 
fruits were characterized by the highest concentration of the component ( 36.37% , on average ) , while  yellow wonder  contained the lowest level of the parameter ( 28.22% ) .
considering the water content in dried material , fruits of studied wild strawberry cultivars slightly differed from each other and statistical analysis did not reveal any significant differences .
regardless of the cultivar , moisture content of air - dried fruits oscillated around 11.10% , on average ( table 2 ) . among compared cultivars ,  baron von solemacher 
fruits were characterized by the highest concentration of the component ( 36.37% , on average ) , while  yellow wonder  contained the lowest level of the parameter ( 28.22% ) .
considering the water content in dried material , fruits of studied wild strawberry cultivars slightly differed from each other and statistical analysis did not reveal any significant differences .
regardless of the cultivar , moisture content of air - dried fruits oscillated around 11.10% , on average ( table 2 ) .
different levels of flavonoids in raw and dried fruits of three wild strawberry cultivars are presented in figure 1 and table 3 .
0.593  mgg ( raw material ) and 1.245  mgg ( dried material ) . on the other hand ,
( 0.471 and 1.178  mgg , resp . , for raw and dried material ) .
significant differences in flavonoids contents over the years of study for both analyzed types of material were observed .
the dried fruits of all studied genotypes were characterized by over twice as high flavonoids amounts as compared to raw fruits .
were the best sources of these compounds 2.840  mgg in raw and 4.987  mgg in dried material ( table 3 and figure 2 ) .
fresh fruits of yellow wonder cv . contained almost twice as low phenolic acids as regina cv . fruits . however , mean values recorded for dried fruits of all analyzed genotypes slightly differed and statistical analysis confirmed that the differences were significant .
changes in tannins contents for all studied wild strawberry fruits were similar as those for flavonoids .
raw fruits contained 2.76% of tannins , on average , while dried ones contained 5.31% ( table 3 and figure 3 ) .
significant influence of all examined factors on tannins contents in studied materials was found on a base of determinations performed .
anthocyanins were another group of substances analyzed in wild strawberry fruits ( table 3 and figure 4 ) .
fruits of regina cv . were the best source of anthocyanins as similar as phenolic acids . from 144.12  mg100  g to 177.07 
mg100  g were recorded in raw fruits of this cultivar , whereas dried fruits contained from 398.54  mg100  g to 460.40  mg100  g. among compared cultivars , the yellow wonder cv . appeared to be the worst since it contained only from 80.97  mg100  g to 99.00  mg100  g ( raw material ) and from 192.52  mg100  g to 236.90  mg100  g ( dried material ) of anthocyanins .
significant differences in the ability to neutralize the free dpph ( diphenylpicrylhydrazyl ) radical by extracts made of examined wild strawberry fruits were recorded ( table 4 ) .
extracts prepared from dried fruits revealed definitely highest ability ( 23.93% ) as compared to raw material ( 13.11% ) .
when comparing studied cultivars , the highest neutralizing capacity was shown by extracts made of regina cv .
the free radicals were worse reduced by extracts prepared from fruits of yellow wonder cv . and baron von solemacher cv .

 fragaria vesca has traditionally been a popular delicious fruit for its flavor , taste , fresh use , freezing , and processing .
morphological , biometric , and agronomical characteristics have been widely used to describe wild strawberry cultivars . in recent years
, cultivated berries have become very attractive for consumers because of potentially beneficial phytochemicals contained in these fruits .
the importance of flavonoids and other phenolics has been suggested to play a preventive role in the development of cancer and heart disease .
considerable data suggests that higher content of flavonoids , phenolic acids , tannins , and anthocyanins in berry fruits contributes to their higher antioxidant activity [ 17 , 25 ] .
following substances should be counted as the most important bioactive components of wild strawberry : phenolic acids ( ellagic , p - coumaric , gallic acids ) , flavonoids ( flavonols , quercetin , and kaempferol ) , proanthocyanidins , and anthocyanins ( pelargonidin , cyanidin ) [ 2628 ] . due to these compounds , the fruits have anticarcinogenic , antioxidant , anticoagulant , immunomodulating , anti - inflammatory , blood pressure , and cholesterol regulating features [ 29 , 30 ] . measuring such parameters is wildly used to evaluate the potential health benefits of breeding material or various agronomic factors .
however , little is known on the phenolic profiles and antioxidant potential of wild strawberry in important local cultivars . in this paper
the differences in the concentrations of secondary compounds determine the nutritional importance of the analyzed cultivars .
furthermore , they provide information on the marketing potential of the 3 cultivars and present an important chemical insight into the popular cultivars grown in this region .
secondary metabolites content in berry fruits varies among species and cultivars , but it can also be affected by growth conditions including environmental factors and cultivation techniques [ 10 , 11 , 3134 ] .
it has been shown that higher growing temperatures ( day and night ) increase the flavonols and anthocyanins contents in strawberries .
authors of the present study , on a base of performed research , proved differentiated contents of biologically active substances : flavonoids , phenolic acids , tannins , and anthocyanins in raw and dried fruits depending on wild strawberry cultivar .
furthermore , they analyzed the antioxidant ability of extracts made of studied materials by means of neutralizing the free dpph radical .
mean content of flavonoids and tannins in fresh fruits of  baron von solemacher  cv .
raw fruits of  regina  cv . were characterized by the highest average concentrations of phenolic acids and anthocyanins : 4.987  mgg and 444.25  mg100  g , respectively . according to antal et al . , the quantity of anthocyanins in raw berries ranges from 30  mg100  g ( fragaria moschata ) to 165  mg100  g ( vaccinium myrtillus ) .
huang et al .   found higher contents of anthocyanins in berry fruits , which correspond with values achieved in the present study for raw fruits of examined wild strawberry genotypes .
in opinion of olsson et al . , the amount of phenolic substances as well as antioxidant activity was different within fragaria x ananassa duch .
evaluated fresh fruits and found that strawberries had total phenolics of 3.680  mgkg fresh weight . as it follows from performed analyses , mean content of phenolic acids for fresh wild strawberry fruits was at the level of 2.314  mgg .
the differences in polyphenol content of strawberry fruit from the literature may be due to the different conditions during the growth of plants ( climatic conditions , temperature , precipitation , and soil conditions ) , the length of the growing season , and harvest date .
they may also be caused by using various analytical procedures or methods identifying the active ingredients by scientists in various centers .
identification of chromatographic methods usually has a lower content of active substances , because its task is to determine the minimum content and separation and identification of individual compounds in the raw material .
commonly used spectrophotometric procedures are based on similar assumptions , so after taking into account differences methods are comparable to those applied in this paper . during the three years of the research , the highest contents of analyzed biologically active substances were recorded in 2013 , while the lowest were recorded in 2012 . in a previous investigation , we found that fresh wild strawberry fruits possess high amounts of bioactive compounds .
however , fresh fruits are not available all year round , being harvested in poland only in june  september .
therefore , it is important to find a proper substitute that could be used when fresh berries are not available .
it was decided to prepare dried fruits , to determine the contents of some important bioactive compounds and their antioxidant potential therein , and to compare them with the same parameters in fresh fruits .
dried fruits have a greater nutrient density , greater fiber content , increased shelf life , and significantly greater phenol antioxidant content compared to fresh fruits .
the quality of the antioxidants in the processed dried fruit is the same as in the corresponding fresh fruit .
data presented in tables 24 indicate diverse contents of biologically active compounds in raw and dried materials depending on the cultivar .
the highest mean concentrations of analyzed substances in air - dried fruits were similar as for fresh ones .
dried fruits of analyzed genotypes were characterized by over twice as high quantities of biologically active substances and antioxidant activity as fresh fruits .
results from the present study are a confirmation of the results achieved by vinson et al .  
as a conclusion , our results clearly demonstrate that considerable variation exists in the phenolic compounds among wild strawberry genotypes .
the obtained results allowed the identification of cultivars which were characterized by the highest content of investigated biologically active substances and the highest ability to free radicals elimination .
the results from the performed experiments also have practical application during the breeding program preparation in order to obtain new cultivars of this species .
therefore , dried fruits are good source of important bioactive compounds and more dried fruits should be recommended to be added to the diet by dieticians and nutritionists .
 chemical analyses carried out in 20112013 aimed at evaluating the contents of flavonoids , free phenolic acids , tannins , anthocyanins , and antioxidant activity ( % ) by means of dpph radical neutralization ability in fresh and air - dried fruits of three wild strawberry cultivars . 
 examinations revealed differences in contents of biologically active substances determined in raw versus dried material depending on the cultivar . 
 mean concentrations of flavonoids and tannins were highest in raw fruits of  baron von solemacher  cv . , which amounted to 1.244  mgg1 and 6.09% , respectively . 
 fresh fruits of  regina  cv . were characterized by the highest average content of phenolic acids and anthocyanins : 4.987  mgg1 and 0.636  mg100  g1 . 
 the pattern of mean contents of biologically active substances analyzed in air - dried fruits was similar . 
 significant differences in abilities to neutralize the dpph radical to diphenylpicrylhydrazine by extracts made of examined wild strawberry fruits were also indicated . 
1. Introduction
2. Experiment
3. Results
4. Discussion
5. Conclusion