this special issue of food biophysics journal contains papers originally presented at the 3rd international symposium on delivery in complex food systems , which was held at wageningen university , the netherlands , from october 18 to 21 , 2009 .
as the subtitle already indicates , the purpose of this symposium is to build a better understanding of the physical processes which are involved in creating food products and which impact their consumption , at all relevant length scales .
the topic is of interest to scientists from academia , industry and government as it relates to the building of basic understanding , to the production of high - quality foods and to development and maintenance of the regulatory framework to protect consumers , the environment and ascertain a healthy competition in the food industry .
this symposium was the third one in what can truly be called a series now , with the first symposium held in lausanne ( ch ) , 20051 and the 2nd one in 2007 in amhurst ( ma , usa).2 in this 3rd symposium a number of talks concentrating on , or taking into account the fate , of common and newly designed food structures during their passage through the human gastro - intestinal tract .
these steps target the actual delivery of the nutrients to the human body which is critical for its biological functionality .
not only are consumers nowadays better informed about the relation between life - style and own health , of which their food consumption pattern is a critical part , there is also a strong development in the regulatory domain to protect the same consumers from misleading claims on food products .
foods with attached health claims which go beyond the normal nutritional content and impact , the so - called functional foods , have to meet all existing requirements and consumers expectations with regard to all sensory aspects , convenience and pricing , but also have to actually deliver the functional ingredient which is linked to the claimed health effect .
the large number of dossiers submitted to the european authorities to assess the validity of functionality claims put forward by companies signals the great commercial interest in such products .
the symposium recognized five different sessions that are to be connected to address the issues above ;
in regard to the preparation of foods , one has to meet boundary conditions on health , deliciousness , ingredient availability and cost . in addition , for both foods prepared at home and at industrial scale , flexibility in terms of formulation is additionally of importance .
all these boundary conditions apply to one or more steps at the same time during the product life cycle : processing , transport , storage , consumption , and digestion .
one is to investigate commonly existing foods on their function in terms of their microstructures and according constituents ( molecular sized ) .
the other is to prepare novel ( micro-)structures and investigate these regarding their possible functions .
the contributions in this session have to be viewed in terms of this latter area .
one important class of ingredients is of course proteins , and their assembly is a key area within food development and production . in the session ,
two excellent contributions were presented in the area of protein / peptide assembly ( by professors gazit , hebrew university of jerusalem , israel , and hammarstrom , linkoping university , sweden ) . in relation to the physics at larger length and time scales ,
an invited lecture was given by professor cipelletti , universit montpellier ii , on the long - time dynamics of microstructural evolution .
the focus in this session was on how techniques and approaches developed in materials science , physics , and biophysics are having an impact in the field of food science and technology .
advances in measurement techniques from the single molecule to the mescopic level were highlighted , with emphasizes on the scientific framework in which their results can be used to advance our understanding of complex food systems .
understanding processes involved in delivery of the functional ingredient in the human gi tract is relatively new and was the focus of the biophysics of nutrient digestion and absorption session .
better understanding of the processes involved methods to model or predict these in an experimental setting and finally meet delivery and regulatory requirements is essential for the functional food area . not only will it help to substantiate the nutritional claims made for the food product , but products which score better on all these aspects are ultimately also the differentiator in the marketplace .
there is a whole cascade of events from food assembly , preparation , to digestive breakup starting in the mouth , to the complex stomach and intestinal events , involving biochemical processes to finally present the functional molecules and nutrients to the absorptive sites at the intestinal wall .
this can be captured in the term bioaccessability and defines the amount of functional ingredient which is available for absorption .
so far , models which mimic the human gastro - intestinal events have been derived from anatomical and enzymatic understanding and less so from , e.g. , a fluid dynamics approach .
this poses a challenge as for ethical , practical , cost constraint reasons , availability of in vitro models with good in vitro in vivo correlations would be ideal .
in order to meet the challenges regarding the understanding of the development , production , consumption and digestion of foods one needs a multiscale approach .
this means that one needs to connect many different scientific fields : physics , physiology , and the science of human perception .
this session was organized as a first , exploratory attempt to bring together scientific developments in these various fields under the umbrella 
complexity ,  which is a well - defined concept in many disciplines such as physics , network theory and sociology .
we are convinced that in the food field the concept of complexity will have a major impact in the future , not only because of the complexity of , e.g. , the physics or physiology , but in particular as the notion of complexity can help to modulate the way different scientific disciplines may interact and evolve together on a common topic , such as a food , food consumption or food digestion .
for the first time in the symposium series , a session emphasizing the relation between food technology and nutrition was organized . in the session , examples were presented of successful products in which physical principles were utilized to create food products and food ingredients with enhanced stability , functionality and release of nutrients . in addition , in the session , conceptual approaches towards the development of new and sustainable food technologies were presented .
the conference was attended by about 160 scientists from academia and industry , and the formal and informal discussions were lively and stimulating , integrating old and new approaches .
we are very pleased to announce that the next symposium , the 4th edition in this series , will be held in the early autumn of 2011 in guelph , canada .
 the wageningen delivery of functionality symposium covered all aspects involved with food structural design to arrive at high - quality foods which meet demanding customer expectations and regulatory requirements . 
 the symposium integrated aspects from the structural organization of foods at molecular and supramolecular scales to dedicated techniques required to describe and visualize such structures , the gastro - intestinal events and how to model these in a laboratory setting , and finally the impact those food structures and ingredients have on the consumer s physiology and on the human perception . as an interdisciplinary platform , bringing together more than 160 researchers from academia and industry , the symposium meanwhile fulfills an important role in the food science community . 
Introduction
Supramolecular Organization in Foods: Glassy Systems, Protein Assemblies, and Lipid Phases
Unraveling Food: Molecular Insights from Spectroscopy, Single-Molecule Techniques and Scanning Probe Microscopy
Biophysics of Nutrient Digestion and Absorption
Food Complexity: Physics, Physiology, and Perception
Food Development: Technologies and Ingredients to Face Nutritional Challenges