FACT AND FICTION: INGREDIENTS AND THEIR USE IN FOOD SYSTEMS
 P. KOVACS, Kovacs Advisory Group, L.L.C., 930 Tahoe Boulevard, #802, Suite 449, Incline Village, NV 89451

The complex interaction of a multitude of molecules forming the stability, texture, taste and nutritional properties of formulated food is neither well understood nor adequately researched. The biological, safety and functionality results of these interactions are often neglected. As a consequence, the formulating and marketing of food ingredient systems has been a long and elusive quest for most, if not all, ingredient suppliers. The lack of understanding of food systems at the molecular level has created too many unfulfilled promises, too much hype and not enough substance in the marketplace. The attempt by many ingredient suppliers to promote simple blended ingredients with little or no technology or proprietary content as ingredient systems, ha proprietary content as ingredient systems, has generated a skeptical customer base which will be difficult to overcome. Furthermore, the well established practice of formulating processed foods in a sequential order, such as texture first, then flavor, has erected its own barriers to the development of formulated food ingredient systems.

Notwithstanding the current situation, opportunities abound to capture sustainable competitive advantage by developing proprietary food ingredient systems at the texture/taste/nutrition interface of formulated foods. This presentation will detail the distinctions between single ingredients, blends, and technology based food ingredient systems. A new paradigm for formulating processed foods will be proposed along with the segmentation of market opportunities by technology, geography and customer base. The required core competencies for ingredient suppliers with ambitions to participate in developing and marketing total ingredient systems will be described.

NEW APPROACHES FOR FUNCTIONAL USE OF MILK PROTEINS IN FOOD SYSTEMS
 J. N. de WIT, Consultant Food Proteins, Nieuweweg 6, 6871 CB, Renkum, The Netherlands
Food products include various proteins with different structural, physico-chemical and functional properties as driving forcunctional properties as driving forces for protein functionality. Protein functionality may be defined as protein behavior in food systems during preparation, processing, storage and consumption. There are no generally accepted schemes for the classification of protein functionality in relation to their specific physico-chemical or functional properties. Although it is generally known that the molecular basis for protein functionality is related to their structure, and their ability to interact with other food ingredients, more understanding of the role of food proteins during and after food processing is required for their effective use in food products.
A new approach for studying protein functionality has been proposed, performed in the following sequence: First, an evaluation is performed of protein related characteristics of a specific food product on the basis of their original proteins and effects of substituted or fortified proteins. Next a working hypothesis is developed to study observed features, either directly by using a basic proteins information, or indirectly by using representative model systems. And finally, results are explained on the basis of structure-function relations of milk proteins.
This approach will be illustrated by using caseinates and whey protein products as functional ingredienein products as functional ingredients in some representative products from aerated desserts, processed cheese, meat products, and surimi-type fish products. Retroactively explained structure-function relations of milk proteins in these food products, are compared with those of predicting functional properties as foaming, emulsifying, waterbinding and gelation properties, respectively. Conclusions recommend the use of basic protein information for explaining observations retroactively rather than to predict protein functionality from simple model systems, previously.

RESEARCH RELATED TO PROTEIN FUNCTIONALITY IN FOOD AND DIETETIC PRODUCTSR. JOST, Nestle R&D Center, Konolfingen, CH-3510 Konolfingen 1, Switzerland

The study of lipid filled whey protein gels has been a main research topic of mine at Nestlé Research labs in the years 1985 to 1992. This research had been motivated by the objective to produce whey protein based O/W food emulsions with high long-term stability and good viscosity- and texture-forming properties. The absence of (other than protein) emulsifiers to achieve this was a desirable feature in this work. The studies carried out in my team revealed the narrow connection which exists between emulsion characteristics and mien emulsion characteristics and microstructure and texture of O/W emulsion-based, heat-induced gels. Homogenization takes a key role in facilitating the inclusion of fat droplets in a coherent gel structure in which the lipids act as a "filler particle".
Our findings in this area have been well received and extended by scientists such as H. G. Kessler, J. Kinsella, J. Aguilera, E. Dickinson, D. Dalgleish, and others who all emphasize the interest in "engineering" food texture via filled protein gels.
In 1990, I was given the opportunity to present some of this work at the XXII Int. Dairy Congress in Montreal as an invited speaker.
A present link with whey protein functionality is through an EU-sponsored working group, in which I participate as an "industrial member". The group called MADGELAS (Molecular Aggregation, Denaturation, Gelation, and Surface Properties) involves scientists from different European dairy research establishments under the chairmanship of Hannah Ri at Ayr and investigates, in a concerted action, the behavior of -lactoglobulin and whey protein preparations more or less enriched in this protein.
Related Publications:
1986: Colloid and Polymer Science 264:631-638. A study of oil 264:631-638. A study of oil-in-water emuslions stabilized by whey proteins. G. Masson and R. Jost.
1985: J. Food Science 51: 440-444/9. Heat gelation of oil-in-water emulsions stabilized by whey protein. R. Jost, R. Baechler, and G. Masson.
1989: Food Microstructure 8:23-28. Heat-set gels based on oil-in-water emulsions: An application of whey protein functionality. R. Jost, F. Dannenberg, and J. Rosset.
1990: 23rd Dairy Congress Montreal. Proceedigs of the XXII Int. Dairy Congress. Action of milk proteins in emulsion of various food systems. R. Jost, F. Dannenberg, and D. Gumy.
1993: Trends in Food Science & Technology 4:283-288. Functional characteristics of dairy proteins. R. Jost

GENETIC ENGINEERING TO IMPROVE NUTRACEUTICAL AND PHYSICO-CHEMICAL FUNCTION OF FOOD PROTEINS
 S. UTSUMI, Research Institute for Fo Research Institute for Food Science, Kyoto Univ., Uji, Kyoto 611, Japan

Genetic engineering is a powerful and promising method to improve protein function in foods. This can be achieved by several approaches as follows: (1) Introduction of a foreign gene: This approach is suitable for alteration of protein compositions of crops. Many attempts based on this approach have been carried out for improvement of nutritional properties; introduction of a gene encoding a protein, which is rich in sulfur containing amino acids or lysine, into legumes or cereals. We succeeded in creation of a rice producing soybean glycinin, which has good physiological (cholesterol-lowering) and physico-chemical functions as well as nutritional property. In this case, we may enhance physiological and physico-chemical functions, and also improve nutritional value. (2) Regulation of gene expression: Enhancement of expression of a gene encoding a desirable protein and suppression of an undesirable protein such as allergens have been successfully carried out. (3) Alteration of a primary sequence: Attempts to alter a primary sequence of a protein to improve its function have accumulated. ts function have accumulated. Successful and unsuccessful attempts to improve nutritional properties of maize zein, French bean phaseolin, field bean legumin, and 2S albumin, and successful attempts to improve functional properties of soybean glycinin (by our group) , wheat HMW-glutenin, egg lysozyme and milk -lactoglobulin will be described.
Key words: protein function, genetic engineering, improvement

DESIGNING THE FUNCTIONALITY OF MILK PROTEIN BY ENZYMATIC MODIFICATION
 H. SWAISGOOD, G. Catignani, X. Huang, V. Valentine, and D. Clare, Dept. of Food Science, Southeast Dairy Foods Center, North Carolina State Univ., Raleigh, NC

Limited proteolysis of whey protein isolate using immobilized trypsin under appropriate conditions results in optimum release of structured fragments of the -barrel domain of -lactoglobulin. Use of immobilized trypsin permits retention of -structure in the predominant 8.4 kDa fragment because a downstream enzyme inactivation is not required. The enzyme-treated whey protein isolate exhibited improved emulsifying activity, better emulsion stability, improved foaming properties, and modified gelling characteristics and gel properties. A means for preparation of immobilized enzyme bior preparation of immobilized enzyme bioreactors using recombinant enzymes is also being developed. Genetic construction of fusion enzymes with streptavidin as an affinity domain allows one-step purification and immobilization from crude lysates of the recombinant cells. Genetic constructs for trypsin-streptavidin and streptavidin-transglutaminase have been prepared.

WHEY PROTEINS AS MICROENCAPSULATING AGENT
 M. ROSENBERG, Dept. of Food Science and Technology, Univ. of California, Davis, One Shields Avenue, Davis, CA 95616
A new functionality aspect of whey proteins (WP), their microencapsulating properties, was investigated in recent years. Microencapsulation is a technique by which liquid droplets or solid particles (core) are coated with a thin film of protective material (wall system). The wall protects the core against deterioration, limits losses of volatile core, and releases the core under desired conditions. Anhydrous milkfat (AMF) was encapsulated by spray drying (SD) in wall systems consisting of WP or mixtures of WP and carbohydrates. Encapsulation yield higher than 95% was accomplished. The encapsulated AMF showed no oxidation during 12-mo storage at 25-50°C, under light. Ethyl butyrate (EB) and ethyl caprylate (ECY) werebutyrate (EB) and ethyl caprylate (ECY) were encapsulated in WP or mixtures of WP with lactose. Wall composition, core-to-wall ratio, SD conditions, and ester type affected volatile retention. Ester retention of 76% and 92% were obtained for EB and ECY, respectively. In all cases, spherical microcapsules with smooth, dents-free surfaces were obtained. The core was found to be organized in the form of small droplets (0.1-0.5 µm in diameter) embedded in the wall matrix. High stability of encapsulated core was attributed to the formation of dense protein-based interfacial films. Whey protein-based microcapsules exhibited molecular-sieve type of micro-porosity that was affected by composition. Results indicated that WP are effective microencapsulating agents for both volatile and non-volatile core materials.

FLOW PROCESSING TO GENERATE FUNCTIONAL FOOD MICROSTRUCTURE
E. J. WINDHAB, Department of Food Science, Swiss Federal Institute of Technology Zürich (ETH) Zentrum, LFO E18, CH-8092 Zurich, Switzerland

The microstructure of complex food systems is one of the most important criteria for quality characteristics such as separation/demixing stability, rheological behaviour, texture and aroma-related sensorial properties. The main mechanism for microstructuring . The main mechanism for microstructuring food systems is to apply mechanical stresses (normal, shear, or inertia stresses) and/or thermal treatment. A well known group of microstructuring flow processes are denoted as dispersing operations using apparatus such as high pressure homogenizers and rotor/stator dispersing turbines. But there is also microstructuring in other flow devices such as extruders, spraying nozzles, scraped surface heat exchangers and even in pipe flow. For typical dispersing apparatus there are many publications which give integral descriptions on specific flow geometries and specific multiphase food recipes but only few which consider the basic fluid dynamics and related rheological aspects. For the second large group of flow processes the microstructuring abilities are in general not specifically taken into account.
To understand the mechanisms of microstructuring in flows the micro fluid mechanics has to be taken into account. Beside the local specific power or energy input the type of flow and in particular the local velocity field has to be considered in detail. Most of the flow fields in multiphase food processing are of laminar nature. This is even the case for typical dispersing flow processes due to the narrow gaps which are used in such devices (high pressure homogenizers, colloid mills)ressure homogenizers, colloid mills) if the viscosity is not waterlike.
Microstructuring laminar flows can be divided into the two main groups of shear- and elongational-flows. In shear flows there is a rotational contribution of the velocity gradient tensor which makes shear flows less efficient in microstructuring compared to elongational flows. A further increase in microstructuring efficiency can be reached in biaxial elongational flows (equibiaxial or planar elongational).
If thermal treatment is superimposed to the mechanical treatment there are synergistic structuring effects. The following examples for microstructuring flow processes/apparatus will be discussed:

a) Ice crystal microstructuring in low temperature extrusion (shear flow)
b) Microemulsification in rotor/stator dispersing devices (comparison of shear and elongational flow fie and elongational flow fields)
c) Emulsification and deagglomeration in nozzle flows (uniaxial and equibiaxial elongational flows)
For all examples demonstrated the microstructural changes are analyzed by microscopic and image analysis means or via appropriate laser scattering/-diffraction methods. Furthermore, the influence of microstructure on the rheological properties and related quality characteristics are included.
KEY WORDS: flow processing, functional microstructure, rheology
References:
Windhab, E., and B.Wolf. Influence of Deformation and Break up for Emulsified Droplets on the Rheological Emulsion Properties. Theoretical and Applied Rheology, edited by P. Moldenaers and R. Keunings, Proc. XIth Int. Congr. on Rheology, Brussels, Belgium, August 17-21, Vol. 2, page 681-683, 1992.


Windhab, E. Influence of Mechanical Forces on the Disperse Structuring of Ice Cream During Continuous Aeration/Freezing Processes. AICHE, Proc. 5th World Congress of Chemical Engineering 1996, 2, 169-175 (1996).


Windhab, E. Food Emulsion Processing with Optimized Rotor-stator Dispersing Devices. AICHE, Proc. 5th World Congress of Chemical Engineering 1996, 2, 236-242hemical Engineering 1996, 2, 236-242 (1996).

Windhab, E. Influences of Processing on Structure-Rheology-Texture Relationships for Colloidal Food Systems. Food Colloids - Proteins, Lipids and Polysaccharides, E. Dickinson (Editor), Royal Society of Chemistry (U.K.), Paston Press Ltd., London, 3-18 (1996).

Wagner T., and E. Windhab. A Spray Crystallization Process for Fat and/or Water Containing Liquids. Engineering & Food; Proc. Int. Conference on Engineering in Foods (ICEF 7); Brighton, England; 14.-17.4.97; Editor: R. Jowitt, Sheffield Academic Press, E 21-25.

Windhab, E. Process - Structure - Rheology Relationships of Multiphase Food Systems. Proc. 1st Int Symp. on Food Rheology and Structure, Zürich; March 16 - 21,1997; Editor: E. Windhab; B. Wolf; Vincentz Verlag Hannover, 1-15.

THE SURFACE BEHAVIOR OF DIFFERENT MILK PROTEINS IN O/W-SYSTEMS PREPARED BY MICROPOROUS GLASS (MPG) EMULSIFICATION
 I. SCHERZE, K. Marzilger, and G. Muschiolik, Friedrich-Schiller-Univ., Institute of Nutrition and Environment, Dornburger Str. 29, D-07743 Jena, Germany

The new method of MPG emulsification opens the opportunity to investigate the emulsifying properties and adsorption behavior of proteins in their native status. The aim of the presenn their native status. The aim of the present work was to study the surface behavior of milk proteins and protein composition of fat globule surface layers in emulsions prepared by MPG at low shear forces. The o/w-emulsions were produced by dispersing the hydrophobic phase (liquid butter fat or sunflower oil) through the MPG of different porosity (Dm = 0.19 or 0.5 µm) into the flowing continuous phase containing the milk proteins. In addition, emulsification by means of high pressure homogenizer was also investigated. The emulsions were characterized by protein adsorption, particle size distribution and creaming behaviour. The protein load values found in MPG emulsions (2,5 ± mg/m2) were lower than those determined for high pressure emulsification (10 mg/m2), and showed little change at varying processing conditions. Using skimmed milk, caseins absorbed in preference to whey proteins, but the preference being smaller than in emulsions by high pressure homogenizer. The surface layer of buttermilk emulsions contained besides caseins and whey proteins small amounts of milk fat globule membranes (MFGM). The MPG emulsification can be used to prepare fat globules with milk protein surfaces of different technological behavior.
Key words: membrane emuy words: membrane emulsification; microporous glass; oil-in-water emulsions; milk proteins; functionality; surface behaviorCategory: surface activity

BIOCHEMICAL AND GENETIC STRATEGIES FOR PROTEIN DESIGN AND THE DEVELOPMENT OF NEW ANTIMICROBIAL LYSOZYME
H. R. IBRAHIM, Dept. of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima Univ., 1-21-24 Korimoto, Kagoshima 890, Japan

The effectiveness of hen egg-white lysozyme in food systems and therapy is actually based on its ability to control the growth of susceptible bacteria. The mechanism by which lysozyme kills the sensitive bacteria is known to be the degradation of the glycosidic beta-linkage between N-acetyl hexosamines of the peptidoglycan layer in the bacterial cell wall. Antibacterial specificity of lysozyme is limited to certain Gram-positive bacteria but much less effective against Gram-negative ones, owing to the presence of the outer membrane permeability-barrier of the latter. Thus, attempts to convert lysozyme to be active in killing Gram-negative bacteria would be an important contribution for modern biotechnology and medicine. This presentation will review our strategies of promoting the bactericidal action of lysozyme to include Gram-negative bacteria.
Our strategy tive bacteria.
Our strategy was based on equipping the enzyme with a hydrophobic carrier to enable it to penetrate and disrupt the bacterial membrane. Two approaches were adopted in which a membrane-binding hydrophobic domain was introduced to the catalytic function of lysozyme. In the first one, medium-chain fatty acids with different lengths of hydrocarbon chain were covalently attached to the molecule. In the second approach, different lengths of hydrophobic peptides were genetically fused into the C-terminus of lysozyme. Both approaches were proved very promising to switch the antimicrobial specificity of lysozyme to include Gram-negative bacteria. A striking mechanism of action of the hydrophobic-fused preparations is the disruption of the electrochemical membrane potential in cooperation with the catalytic function of lysozyme. This result has invited another approach to elaborate a stronger and safer antimicrobial agent by utilizing the catalytic function of lysozyme to deliver a hydrophobic antibiotic to the killing site (the inner membrane) of bacteria. Particularly remarkable was the lysozyme-Phenolic aldehyde conjugate, which showed strong bactericidal activity to Gram-negative and -positive bacteria, having good potential use in formulated food and drug systems.

APPLICATION OF WHEY PROTEINS AS EDIBLE COATING FOR HARD CHEESE AND CAKES
 H. KORHONEN, Food Research Institute, Agricultural Research Center of Finland, FIN-31600 Jokioinen, Finland

Since the early 1990's there has been an increasing interest in using whey proteins as edible films and coatings. Whey proteins are suitable for this purpose because of their good solubility, good emulsifying and gelation properties and high nutritional value. Whey protein coatings are also good barriers for oxygen and carbon dioxide. Their water vapor permeability is, however, high but it can be lowered by adding lipids as emulsions or layers (Chen, 1994; Gennadios et al., 1994; Maté and Krochta, 1996).
The aim of our study was to develop whey protein derived edible coating for different types of foods to prevent lipid rancidity, waid rancidity, water evaporation and altogether extend their shelf-life. The selected foods were hard cheese and cake. Also, mechanical properties and water permeability of whey protein films were studied as a function of plasticizer concentration. Edam cheese was used in experiments and edible coatings were cast from whey protein isolate (WPI), whey protein concentrate (WPC) and -lactoglobulin. Glycerol was applied as plasticizer. Also, laminar structure was tested by covering protein-glycerol layer with lipid (butter oil or monoglyceride). Cheese without any coating and cheese with paraffin were used as controls. The cheese was stored at 4°C and the weight was checked for six weeks. Cakes contained eggs, sugar, butter, flour, water, and baking powder and were baked 40 min. at 165°C. Cakes were brushed with WPI or WPI-glycerol solution. As control a cake without any coating was applied. Cakes were packed in polypropylene and stored at the room temperature 8 weeks. The weight, hardness, aw and organoleptic properties were tested after 1, 2, 5, and 8 weeks.
In both Edam cheese and cake it was possible to prepare a coating which was solid, blank and adhered to the object. Practically no difference was found between the weight of cheese covered and not covered with protein coatot covered with protein coating. The results with various protein coatings were comparable to each other. When the cheese was coated with WPI-glycerol and butter oil, the weight was reduced by 15% in six weeks, whereas the weight of the control cheese diminished 28% in weight. The weight of paraffin-coated cheese did not diminished during six weeks. The cakes with coatings remained softer than the control cakes. The difference between the WPI-glycerol coating and the control was 32% after 2 weeks and 96% after 8 weeks. Water activity in cakes did not changed markedly during the storage. According to sensory analysis the control cakes crumbled easily unlike the coated cakes. The coated cakes were ranked higher by their appearance during all the storage time. The structure of WPI-coated cakes was rated markedly better than that of control cakes but in WPI-glycerol coated cakes some stickiness was sensed. Even after the storage of eight weeks the coated cakes had no old flavour unlike the control.

References:

Chen, H. (1994) J. Dairy Sci. 78:2563-2583.

Gennadios, A., McHugh, T.H., Weller, C.L. and Krochta, J.M. (1994) in Edible Coatings and Films to Improve Food Quality (J.M. Krochta, E.A. Baldwin and M. Nisperos-Carriedo, eds.), pp. 201-277 Technomperos-Carriedo, eds.), pp. 201-277 Technomic Publishing Co., Lancaster, Basel.

Maté, J.I. and Krochta, J.M. (1996) J. Agric. Food Chem. 44:3001-3004.

Key Words: Whey; edible, film, cake

SOY AND DAIRY PROTEIN ADDITIVES IN MODEL MEAT SYSTEMS
 J. REGENSTEIN, Cornell Univ., 112 Rice Hall, Ithaca, NY 14853-5601

Meat proteins are relatively expensive. They are also particularly functional, as can be seen by the large range of processed meat products that are consumed around the world. Many less expensive proteins are being proposed as additives to complement or supplement meat proteins in processed meat products. However, there is limited information about the interaction of these commercial proteins with the muscle proteins. Using time emulsification, i.e., where a fixed ratio of oil to water (protein) is emulsified for a fixed time period and then centrifuged to obtain a relatively stable cream layer; followed by a four day emulsion stability test, i.e., loss of weight over four days of the cream layer; the interaction of soy and dairy proteins designed for use with meat systems could be evaluated. Different muscle preparations, e.g., myosin, natural actomyosin, and exhaustively washed muscle, i.e., muscosin, and exhaustively washed muscle, i.e., muscle subjected to both an exhaustive low and high salt washing, have been examined with a limited number of soy and dairy proteins designed for use in meat systems. The initial meat protein level was selected to provide an intermediate stability and the benefit of the commercial additive on the stability of the cream layer is then measured. In general, the additive proteins provided, at best, a limited improvement in stability. Even in those cases where additional stability is provided, the improved stability is much less than that for an equivalent amount of the meat protein itself. Further work with model "meat emulsions" is needed to confirm these observations.

PRESERVING QUALITY ATTRIBUTES OF APPLE JUICE BY MEANS OF NON-THERMAL PRESERVATION TECHNIQUES
 E. ORTEGA-RIVAS1, E. Zárate-Rodríguez1, and G. V. Barbosa-Cánovas2, 1Dept. of Chemical Sciences, Univ. of Chihuahua, Apdo Postal 1542-C, Chihuahua, Chih, MEXICO, 2Biological Systems Engineering, Washington State Univ., Pullman, WA 99164-6120.

Non-thermal food preservation processes are considered to be more energy efficient and to preserve better quality attributes than conventional uality attributes than conventional processes. Membrane ultrafiltration and pulsed electric fields technology are two of these mentioned non-thermal processes. In ultrafiltration, quality attributes are preserved by a combination of factors such as pore size, membrane type, and operation conditions. In pulsed electric fields technology, the important processing variables for quality improvement are wave shape, pulse time, pulse frequency, electric field intensity, and number of pulses. A study was carried out to compare these two cold sterilization methods in pasteurizing apple juice. For the ultrafiltration experiments, 10,000 and 50,000 pore size polysulphone membrane cartridges (PM10 and PM50) were studied. In terms of the pulsed electric fields experiments, intensity of electric field and number of pulses were investigated. Comparisons between ultrafiltration and pulsed electric fields showed that microbial inactivation is possible by using both techniques. However, quality attributes were slightly different. Significant relative color changes were observed for both techniques. Apparently, in ultrafiltration, these changes depended on pore size, transmembrane pressure, and percentage of recuperation while in pulsed electric fields depended on electric field intensity and number of pulses.

ANTIMICROBIAL PROPERTIES OF THE MULTIFUNCTIONAL INGREDIENT MONOLAURIN
D. L. MARSHALL, Dept. of Food Science and Technology, Mississippi State Univ., Box 9805, Mississippi State, MS 39762

Monolaurin, the glycerol monoester of lauric acid, possesses two main functional characteristics when used as a GRAS food ingredient. As a monoglyceride, monolaurin has emulsifying ability. Lauric acid has the greatest antimicrobial activity of all medium to long chain aliphatic fatty acids. This antibiotic effect is magnified when the fatty acid is esterified to polyhydric alcohols such as glycerol or sucrose. Greatest antimicrobial activity of esterified fatty acids is achieved when few hydroxyls are esterified. Hence, monoester congeners display greatest activity.

Monolaurin is active primarily against Gras active primarily against Gram-positive pathogenic and spoilage bacteria. As an example, the minimal inhibitory concentration of monolaurin to the human foodborne pathogen Listeria monocytogenes is 16 ppm. The spectrum of activity of the molecule can be broadened when combined with other substances. For example, when combined with a cation chelator such as EDTA or citrate, monolaurin becomes active against Gram-negative bacteria. Antimicrobial effects of monolaurin also increase with decreasing pH, aw, and temperature. Furthermore, synergistic antimicrobial interactions between monolaurin and a number of other food ingredients such as phosphates, antioxidants, and acidulants can be observed. The antimicrobial potential of monolaurin should not be overlooked when designing foods.

WHEY PROTEIN-BASED EDIBLE FILM SYSTEMS FOR ENHANCING FOOD QUALITY AND SAFETY
 H. CHEN, Northeast Dairy Foods Research Center, Dept. of Nutrition and Food Sciences, The Univ. of Vermont, Burlington, VT 05045

Whey proteins have been studied as the primary ingredient for potential applications as an edible package of food to enhance the product quality and safety. The success of such an attempt relies on a thorough understanding of various factors that in understanding of various factors that influence the physicochemical and functional properties of the films. Essential functional properties of whey protein-based edible films including permeability and diffusivity, mechanical and viscoelastic behaviors, thermal properties, storage stability, antimicrobial performance, and sensory qualities on selected foods will be discussed. Impact of hydrophilic and hydrophobic interactions between whey proteins and assorted hydrophobic materials on the composite film performance will be reviewed. Effects of homogenization, microfluidization, and ultrasonic processes on the film functional properties will also be examined.

EFFECT OF STORAGE TIME AND TEMPERATURE ON SOLUBILITY OF BEEF AND GOAT PROTEINS
 A. TOTOSAUS, and I. Guerreo, Dept. de Biotecnologia, Universidad Autonoma Metropolitana, Apartado Postal 55.-535, c.p. 09340, MEXICO, D.F.

Frozen storage, applied to minimize biochemical and microbial reactions in meat, notably alter functional characteristics of muscle proteins. The main property affected is solubility, who affects the others, which represents an equilibrium between and water. In this study solubility of meat extracts was evaluated as a result of temperature and time of storage. Goat and beef cuts were vacuum packeat and beef cuts were vacuum packed and stored during 3 weeks at 4, -20 and -63°C. Proteins extracts were adjusted to 10 mg/ml of protein and centrifuged at 25,000 × g during 30 min. Goat has a higher pH as compared to beef, and had no significant differences between treatments. Freezing and thawing promotes formation of aggregates due to protein dehydration. Water displacement due to formation of ice crystals cause cross-linking and incomplete rehydration, since protein-protein interaction is stronger than protein-water. The aggregation is reflected in loss of solubility.

UPDATE ON THE STICKY DOUGH FACTOR IN 1B/1R SOFT WHEATS
 M. G. URIYO1, S. S. Schwarzlaff1, W. E. Barbeau1, J. M. Johnson1, and C. A. Griffey2. Dept. of Human Nutrition, Foods, and Exercise, College of Human Resources and Education1 and the Dept. of Crop and Soil Environmental Sciences, College of Agriculture and Life Sciences2, Virginia Polytechnic Institute and State Univ., Blacksburg, VA 24061

Translocation of the short arm of the 1R chromosome of rye (Secale cereale L.) into wheat (Triticum aestivum L.) increases disease resistance and grain yields but doughs made from some 1B/1R hard doughs made from some 1B/1R hard wheats are unacceptable for breadmaking because of mixing intolerance and excessive stickiness. Presently, little is known about the effects of the 1B/1R translocation on the flour quality and end-uses of soft wheats. Thus, two of our objectives were to assess the dough stickiness of some Virginia grown 1B/1R and non-1B/1R soft wheat flours and the baking performance of these two sets of flours when made into cookies, biscuits, and cakes. A third objective was to determine if the "sticky dough factor" in 1B/1R wheats is a ferulic acid ester moiety residing within the water-soluble pentosan fraction of doughs, as claimed by Chen and Hoseney, and whether this factor acts independently or via unknown interactions with other dough components.
This update will report on progress in meeting our third objective. Four soft wheat flours (sticky and non-sticky 1B/1R flours, and sticky and non-sticky non-1B/1R flours) were chosen for tensile measurements, stickiness testing of reconstituted flours and magic-angle 13C NMR analysis. 1B/1R flours had significantly lower dough strain values than non-1B/1R flours. Strain values and dough stickiness were found to be related; VA54-211 exhibited the greatest stickiness and had the lowest strain value, while VA52-22 was the leas, while VA52-22 was the least sticky and had the highest strain value. The addition of the water-soluble fractions of sticky doughs increased the dough stickiness of only one of the non-sticky base flours (gluten and starch fractions) which contradicts Chen and Hoseney's hypothesis. Proton relaxation times were greater for the starch component (at 62 ppM) of a non-sticky, non-1B/1R dough than for the three other doughs, which suggests that there may be greater (or at least somewhat different) starch-water interactions in this dough than in others.

CONFORMATIONAL ANALYSIS OF THE HYDROPHOBIC PEPTIDE ALPHA-S1-CASEIN (136-196)
 H. M. FARRELL, and M. H. Alaimo, United States Dept. of Agriculture, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038

Hydrophobic interactions are important in the self-association of milk proteins, including S1-casein. The extent to which casein interaction sites are influenced by local secondary structure is not widely known. Both primary amino acid sequence and local secondary structure are shown to affect the self-association of the hydrophobic peptide S1-casein (136-196). The peptide is aggregated at low concentrations (7 µ and above), as determined by 1H NMR measurements. e), as determined by 1H NMR measurements. Increase in temperature is shown to induce side chain mobility (melting) as indicated by both 1H NMR and near-UV CD measurements. As determined by far-UV CD, there is also a loss in the global amount of extended structure with increasing temperature, while -turn structures and some aromatic dichroism are conserved at temperatures as high as 70°C. Similar retention of structure occurs at pH and in 6 guanidine HC1. The observed stability of -turns and some side chains in S1-casein (136-196) supports previous assumptions that hydrophobic, proline-based turns are important interaction sites in the self-association of S1-casein, and possibly in the formation of the calcium transport complexes, the casein micelles. It may be speculated that these areas represent a type of "molten globule" structure forS1-ture forS1-casein.

PREPARATION AND PROPERTIES OF SOY PROTEIN-BASED BIOPOLYMER FILMS
 N. HETTIARACHCHY, L. Were, and M. Yildirim, Dept. of Food Science, Univ. of Arkansas, 272 Young Avenue, Fayetteville, AR 72704

Edible and biodegradable polymer films offer alternatives to synthetic packages without the environmental costs. Crosslinking soy protein with other secondary components has successfully produced films with enhanced film properties. Soy protein-based biopolymers have been produced by crosslinking soybean 11S globulin and whey protein isolate using transglutaminase. Tensile strength values of transglutaminase crosslinked films were two times greater than those of the homologous controls. A positive correlation between puncture strength and tensile strength values was detected. No differences were detected in film thickness among the transglutaminase crosslinked films. The protein polymer network of transglutaminase crosslinked films was resistant to solubilization in aqueous buffers at various pH, but was protease digestible.
Crosslinking soy protein isolate and wheat gluten with added cysteine also resulted in films with enhanced mechanical and barrier properties compared to soy protein control films. Composite soy proteprotein control films. Composite soy protein-gluten films were thicker than the soy protein control films. Tensile strength was highest at pH 7.0 compared to pH 3.0, and 9.0. Puncture strength values showed similar trends to those for tensile strength. The crosslinking reactions can be used to produce films with desirable mechanical properties. These films could find application in products including meat pies that require high water vapor permeability or as coatings for low or intermediate moisture foods, e.g. nuts.

FUNCTIONALITY OF PALM OIL AS A STABILIZER IN PEANUT BUTTER
 K. J. ARYANA, A.V.A. Resurreccion, M.S. Chinnan, and L.R. Beuchat, Center for Food Safety and Quality Enhancement, Univ. of Georgia, Griffin, GA 30224

Free oil separation is a major problem in unstabilized peanut butter. Studies have shown that palm oil is an effective stabilizer in peanut butter. The objectives of our investigations were to study the effect of palm oil on textural attributes, viz. hardness, cohesiveness and adhesiveness, to elucidate the influence of palm oil on oil holding capacity and to study the impact of palm oil on accelerated oil separation. Peanut butter was made with the addition of palm oil levels of 1.5, 2 and 2.5% (w/w of peanuts) along with a contrand 2.5% (w/w of peanuts) along with a control. Samples were stored at 0, 21, 30, and 45°C for 150 days. Storage time influenced hardness, adhesiveness, cohesiveness and oil content within samples. Cohesiveness, adhesiveness and oil content in the product at bottom layer in the container were lower at 21, 30, and 45°C when compared with values at 0°C. Palm oil imparted a significantly better oil holding capacity to the product, indicating good stabilizing potential.
Key words: Palm oil, stabilizer, peanut butter, oil separation.

STRUCTURE-FUNCTION RELATIONSHIPS OF SOYBEAN -CONGLYCININ CONSTITUENT SUB-UNITS
 N. MARUYAMA, and S. Utsumi, Research Institute for Food Science, Kyoto Univ., Uji, Kyoto 611, Japan
Elucidation of structure-function relationships of soybean -conglycinin is required for increasing usage of soybean. Therefore, it is desired to prepare -conglycinin homotrimers composed of only one of three constituent sub-units , ´, and . Escherichia coli expression was used for the normal and the deletion mutants lacking the extension regions of the and ´ sub-units. Effect of N-linked glycans on functional properties were examined. Analyses of solubility, surface hydrophobicity, thermostability, heat-i hydrophobicity, thermostability, heat-induced association, and emulsifying ability of the recombinant normal and mutant sub-units and the native -conglycinin indicated that (1) the individual subunits show characteristic functional properties; (2) the extension regions play an important role in solubility of the and ´ sub-units and their aggregates; (3) thermostability and surface hydrophobicity are defined by the core regions; (4) the N-linked glycans have no effect on thermostability; and, (5) the extension regions and the N-linked glycans, in addition to structural stability, are important factors for emulsifying abilities. These facts indicate that we can produce many kinds of end products by selecting soybean varieties containing -conglycinin with different sub-unit compositions. This study will help elucidating principles related to soybean breeding. (This work was supported in part by a grant from Program for Promotion of Basic Research Activities for Innovative Biosciences.)
Key words: soybean, -conglycinin, structure-function relationship

CURRENT RESEARCH ON FLAVOR ENCAPSULATION AND CONTROLLED RELEASE
 G. A. REINECCIUS, Dept. of Food Science and Nutrition, Univ. of Minnesota, 1334 Eckles Avenue, St. Paul, MN 55108 U1334 Eckles Avenue, St. Paul, MN 55108 USA

We have an ongoing research program devoted to flavor encapsulation. Our current work in this area is focusing on emulsion stability. Emulsion stability may be important for either the encapsulation process itself or a final product application. In terms of process considerations, often an emulsion is required to insure uniformity of flavoring strength, adequate flavor retention and/or oxidative stability during storage (e.g. spray drying). Alternatively, the emulsion may be core to the process as it is in coacervation. Final application needs may or may not require a very good emulsion. For example, a cake icing flavor does not require a good emulsion while a reconstituted beverage flavor does.
In this presentation, I will discuss the emulsion needs of several methods for flavor encapsulation and then go into our current research in this area.

THE ROLE OF VARIOUS COCOA BEANS, CHOCOLATE, LIQUORS, EXTRACTS, AND COCOAS IN DAIRY FOOD SYSTEMS
A. P. HANSEN, Dept. of Food Science, North Carolina State University, Box 7624, Raleigh, NC 27695

STRUCTURAL CHARACTERISTICS OF SOYBEAN -CONGLYCININ CONSTITUENT SUB-UNITS
 S. UTSUMI, M. Adachi, and N. Maruyama, Research Institute for Food Sciuyama, Research Institute for Food Science, Kyoto Univ., Uji, Kyoto 611, Japan

Soybean proteins are important food proteins and are composed of two major components, glycinin and -conglycinin. -Conglycinin is inferior to glycinin with respect to nutritional and functional properties. Therefore, it is desirable to improve properties of -conglycinin for expansion of soybean usage. To attain this, elucidation of structure-function relationships of -conglycinin is required. At first, an attempt was made to investigate structural characteristics of -conglycinin constituent sub-units using Escherichia coli expression system, since -conglycinin is composed of three sub-units , ´, and , and exhibits complicated molecular heterogeneity. The and ´ sub-units contain the extension regions (, 125 residues; ´, 141 residues) in addition to the core regions the core regions (416-418 residues) which are common to all three sub-units. Thus, an E. coli expression system was constructed for individual sub-units and deletion mutants lacking the extension regions. Also, the effect of the N-linked glycans was examined on the structural characteristics since recombinant proteins expressed in E. coli are not glycosylated although -conglycinin is a glyco-protein. The circular dichroism profiles, fluorescence intensities, and density gradient centrifugation patterns of the recombinant proteins compared to the native -conglycinin indicated that all recombinant proteins have correct conformation. Structural analyses indicated that (1) extension regions and the N-linked glycans contribute to the dimensions of the -conglycinin trimers, but not to the densities; (2) the surface hydrophobicity and the thermostability are different among the sub-units and are conferred with the core regions. These facts suggest that the individual sub-units have different functional properties. In order to know the intrinsic structural features of the individual sub-units in detail, X-ray crystallography of some of these recombinant proteins is in progress. (This work was supported in part by a grant from Program for Promotion of Basic Research Activit Promotion of Basic Research Activities for Innovative Biosciences.)
Key words: soybean, -conglycinin, structure

BIOTECHNOLOGY AND ITS IMPACT ON STARCH STRUCTURE AND FUNCTIONALITY
 B. P. WASSERMAN, Dept. of Food Science, Rutgers Univ., Cook College, 65 Dudley Road, New Brunswick, NJ 08901-8520

Starch is a vital food ingredient and also serves as a source for numerous non-food industrial and consumer products.  Starch function is directly related to structural attributes such as monosaccharide composition, linkage orientation, charge properties, degree of branching and polymer size.  Two distinct lines of starch polymer research are now converging.  Chemical studies have linked starch fine structure and functionality. Biochemical and genetic studies are providing detailed knowledge of starch biosynthetic enzymes and their regulation. Metabolic engineering of starch biosynthetic enzymes has the potential to enhance starch yields and to produce starches of highly-controlled size, shape and charge.  For this reason, it is critically important to understand the enzymatic mechanism of starch biosynthesis.  This presentation will focus on prospects for bioengineering of starches and their chemically-modof starches and their chemically-modified derivatives.  In plants, the starch biosynthetic pathway consists of three primary enzymes.  Rapid progress has been made towards characterizing the genes encoding the various isoforms of enzymes.   Each of these genes is amenable to metabolic engineering, and as a result, transgenic plants with altered starch levels and structural properties have been produced.  Technical problems remaining to be overcome and prospects for the production of functionally-advanced starches will also be discussed.

FOOD SYSTEM FUNCTIONALITY OF NOVEL MULTIFUNCTIONAL INGREDIENT: LIPRO
Z. U. HAQUE, Dept. of Food Science and Technology, Mississippi State Univ., Mississippi Agric. and Forestry Exp. Station, Southeast Dairy Foods Research Center, Box 9805, Mississippi State, MS 39762

RHEOLOGICAL PROPERTIES AND MICROSTRUCTURE OF MONODISPERSED O/W EMULSION AGAR GEL
S. GOHTANI, K.-H. Kim, and Y. Yamano, Department of Biochemistry and Food Science, Kagawa University, Miki, Kagawa 761-07, Japan

Effects of oil droplet on the rheological properties and microstructure of monodispersed O/W emulsion agar gel were investigated by mechanical measurements and SEM observation. The l measurements and SEM observation. The monodispersed emulsions for aqueous 1.0% polyglycerolesters of fatty acid solution and corn oil were prepared by microporous glass (MPG) membrane emulsification. The monodispersed emulsions with average droplet sizes of 1.5+-0.15, 3.3+-0.31, 6.5+-0.65 and 12.2+-1.21um were employed. Agar powder (1%) was dispersed in the emulsion and dissolved by heating and then the O/W emulsion agar sol was gelated by cooling.
The stability of oil droplets was maintained throughout the preparation of the emulsion gels and the oil droplets dispersed uniformly in the gels. The compressive stress, strain and energy of emulsion gels decreased with increases in both oil droplet size and oil volume fraction, while those properties of emulsion gels determined by puncture test showed almost no change. Values of dynamic viscoelastic properties of the emulsion gel were almost constant as oil droplet size increased. Cryo-SEM observation revealed that oil droplets aggregated in the emulsion gel and that the gel had some void spaces between gel network and the oil droplet aggregate. Gel strands of the emulsion gel did not cover the oil droplets completely.

EFFECT OF AVERAGE SIZE AND SIZE DISTRIBUTION OF OIL DROPLET ON STABILITY OF O/W EMULSION
Y. YAMANO, and S. GohLSION
Y. YAMANO, and S. Gohtani, Department of Biochemistry and Food Science, Kagawa University, Miki, Kagawa 761-07, Japan

Effects of average size and size distribution of oil droplet on the stability of O/W emulsion were investigated by using monodispersed 0.05% aqueous SDS solution/kerosene emulsion and polydispersed emulsion of the mixes monodispersed emulsions. The monodispersed O/W emulsions were prepared by microporous glass (MPG) membrane emulsification. The monodispersed emulsions with average droplet sizes of 1.8+-0.14, 3.4+-0.30, 3.5+-0.33 and 4.5+-0.33um and the polydispersed emulsons with average droplet sizes of 2.6+-0.72 and 3.9+-0.58um, named E1 and E2, were employed. The emulsions were aged being rotated for 2 weeks to prevent creaming at 25C. The stability of the emulsions were estimated by decreasing ratio in the droplet number of the emulsions during aging.
The decreasing ratio in the droplet number of monodisperse emulsions increased with an increase in both average droplet size and standard deviation of size. The decreasing ratio of E2 was higher than that of E1. For all emulsions, the decreasing ratio increased with an increase in the droplet size. The decreasing ratio of rapid rotation was larger than that of slow rotation, in spite of high preventive effecttion, in spite of high preventive effect of rapid rotation to creaming. These results show that the stability of emulsion of large droplet size is lower than that of emulsion of small size regardless of the creaming effect.

WAVELENGTH-DEPENDENT TURBIDOMETRIC ANALYSIS OF GEL FORMATION

T. P. MOODY, Dept. of Biochemistry and Molecular Biology, Univ. of New Hampshire, Biological Science Center, 46 College Road, Durham, NH 03824-3544

Turbidity can be a useful means for monitoring the formation of gels. The amplitude of the turbidity provides information regarding the size of the scattering species, while the wavelength-dependence of turbidity is sensitive to the shape of the scattering particle. Existing theortetical models for analyzing the amplitude and wavelength-dependence of turbidity have been incorporated iy have been incorporated into a computer program in an attempt to extract relevant structural information during the course of gelation. By simultaneously fitting the turbidity amplitude and wavelength dependence, the high correlation between size and shape information is reduced. Analysis of data from beta-lactoglobulin reveal both the promise and the limitations of this approach.

ANTIOXIDANT ACTIVITY OF WHEAT MILLING FRACTIONS

L. GAO, S. X. Wang, B. D. Oomah, and G. Mazza, Food Research Program, Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, British Columbia, V0H 1Z0, Canada

The millstreams of three Canadian wheats were used to determine the contents and distribution of antioxidant activities, total phenolics, tocopherols, tocotrienols. Total phenolics ranged from 1,000 mg/kg in flours to 3,630 mg/kg in bran. Total tocopherols determined by HPLC ranged from 72.2 mg/kg for Neepawa bran to 177.4 mg/kg for Katepwa bran. Columbus wheat contained an intermediate level of 90.3 mg of tocol/kg. The distribution of antioxidant activity in the milling streams varied significantly, with bran being the most potent and flour the weakest. The antioxidant activity was significantly related, and attributed primarily toy related, and attributed primarily to total phenolics and tocopherols.

WORKSHOP: THE ROLE OF NATURAL AND ARTIFICIAL FLAVORS IN FOOD SYSTEMS
 A. P. HANSEN, Dept. of Food Science, North Carolina State University, Box 7624, Raleigh, NC 27695

WORKSHOP:ANOTHER DIMENSION OF FOOD PROTEIN FUNCTIONALITY -- KOSHER AND HALAL CERTIFICATION
 J. REGENSTEIN, Cornell Univ., 112 Rice Hall, Ithaca, NY 14853-5601

In the Northeastern United States it is estimated that almost 40% of the grocery SKUs (stocking units) are kosher (Jewish) and/or halal (Muslim) certified. Over 35 billion dollars worth of products in the United States are kosher and/or halal certified. Both ingredients and finished products are subject to these important religious laws. This talk will review some the major rules required to meet kosher and halal standards: 1) the allowed animals (from which foods and ingredients can be derived) for both kosher and halal; 2) the removal of blood for kosher; 3) the separation of meat and dairy for kosher; 4) the prohibition of alcohol for halal; and 5) the special plant-based issues related to the Jewish holiday of Passover (late March or April). From this background, we will then focus on rules that affect the food ingredients arena, including broad issues like the current status of biotechnology and preparing equipment for kosher or halal production; along with more specific issues such as why there is so much more kosher whey than kosher cheese and which gelatins are acceptable for both the kosher and halal markets.

WORKSHOP: FLAVOR ENCAPSULATION METHODS

G. A. REINECCIUS, Dept. of Food Science and Nutrition, Univ. of Minnesota, 1334 Eckles Avenue, St. Paul, MN 55108

t. Paul, MN 55108