Protein-starch interaction

In many foods, both starch and protein can be encountered so that understanding interactions between them would be useful. The selectivity in interaction between proteins and starches is best seen in results of dynamic rheological studies. The results depend upon the molecular structure of protein, the starch state of the granules and the amylose/amylopectin ratio, the composition of protein and starch, as well as the phase transition temperatures are important factors influencing protein-starch interaction. Because proteins and starches are thermodynamically different polymers, their presence together may lead to phase separation, inversion, or mutual interaction with significant consequences on texture (Morris, 1990). 

Interfacial interaction between silicone and protein/starch microparticle, 3 and the use of polysiloxanes having hydrophilic groups for the stabilization of proteins against denaturation, 4 were studied. 

Quality of a food product is related to its sensorial (shape, size, color) and mechanical (texture) characteristics. These features are strongly affected by the food structural organization (Stanley, 1987) that, according to Fardet et al. (1998), can be studied at molecular, microscopic, and macroscopic levels. In particular, micro structure and interactions of components, such as protein, starch, and fat, determine the texture of a food that could be defined as the external manifestation of this structure (Allan-Wojtas et al., 2001). 

Many pyrazines were isolated and identified in cooked foods, especially in cooked meats (27). Pyrazines comprised over 40% of the volatile compounds found in cooked pork liver (28). Two pyrazines, 2-methyl-3(or 6)-pentylpyrazine and 2,5-dimethyl-3-pentylpyrazine were among 52 volatiles identified as lipid-protein-carbohydrate interaction products in a zein regular or waxy corn starch-corn oil model system (7). 

Jones, M.G.,Wilson, K. 1976. Milk protein-amylose interaction in solution. Starch 28, 338-341. 

The main drawback to the widespread use of polymer-polymer aqueous two-phase extraction has been the high cost of fractionated dextran. Crude dextran has been used with some success for the purification of enzymes but is much too viscous for many applications. Conversely, polymer-salt systems have relatively low viscosities, separate rapidly, and are inexpensive. Unfortunately, they lack selectivity and cannot be used for affinity partitioning in most cases since the high salt concentrations interfere with the protein-ligand interaction. The starch derivatives are reasonable alternatives for bottom phase polymers but have been hampered by low solubilities and the tendency for gel formation. Tjemeld has reported that chemically modified starches i.e. hydroxypropyl starch... 

Bienkiewicz, G., 2001, Influence of fish lipids-protein and fish lipids-starch interaction on extractability of lipids and content of n-3 polyunsaturated fatty acids, Ph.D. thesis, University of Agriculture Szczecin, (in Polish). 

Most of the data on hpid-starch interactions was derived during studies on dough making and extrusion, wherein the material studied contained, in addition to starch, proteins, also easily interacting with lipids. 

Chu, C.L., Chiang, B.H., and Hau, L.B. 1995. Lipid-protein and lipid-starch interactions during extrusion of soy protein isolate and rice flour blend, J. Food Sci., 22(6), 714. 

Most stains consist of colored substances of natural origin belonging to the polyphenol, carotenoid, or chlorophyll class. Artificial food colorants, cosmetic ingredients, and decorative dyes complete the stain portfolio. Very often stains are complex mixtures of spilled food preparations or beverages. Combined with oils, fats, or other organic material, such as proteins, starch, or waxes, the properties of stains are quite different from those of isolated dyes. Only a small proportion of all stains is fixed on surfaces by physical adhesion. On fibers, in particular, strong interactions often result in covalent bond formation. This process is more important on cotton than on synthetic fabrics. 

Procyanidins have been considered antinutritional compounds because they can interact with proteins, starch, essential amino acids, and carbohydrates and inhibit certain enzymes [121-123]. This binding depends on the degree of polymerization the larger molecules tend to bind more efficiently [7]. However, at the dose present in cocoa no adverse effect has been observed [124, 125]. In addition, the level of flavonoids required to induce mutations and cytotoxicity may not be physiologically achievable through dietary sources however the use of flavonoid supplements could result in... 

Eliasson, A.C., and Larsson, K. 1993. Cereals in Breadmaking. Marcel Dekker, New York. Erlander, S.R., and Erlander, L.G. 1968. Explanation of ionic sequences in various phenomena. X. Protein-carbohydrate interactions on mechanisms of staling of breads. Starch/ Staerke 21 305-315. 

Molecular Interactions. Various polysaccharides readily associate with other substances, including bile acids and cholesterol, proteins, small organic molecules, inorganic salts, and ions. Anionic polysaccharides form salts and chelate complexes with cations some neutral polysaccharides form complexes with inorganic salts and some interactions are stmcture specific. Starch amylose and the linear branches of amylopectin form inclusion complexes with several classes of polar molecules, including fatty acids, glycerides, alcohols, esters, ketones, and iodine/iodide. The absorbed molecule occupies the cavity of the amylose helix, which has the capacity to expand somewhat to accommodate larger molecules. The starch—Hpid complex is important in food systems. Whether similar inclusion complexes can form with any of the dietary fiber components is not known. 

Extrusion texturization minimizes the water binding capacity of dairy protein products, in decreasing order, WPI > WPC > NDM, as temperature increases, making them interact better with starch. 

Whey may be substituted for starch by as much as 25% in extruded corn snacks, but the product does not puff as much as com alone, as the water-holding whey protein does not react with the starch matrix (Onwulata et al., 1998). WPCs or isolates can be added along with starch to create expanded snack foods with boosted nutritional content however, without texturization, whey proteins in amounts larger than 15% may interfere with expansion, making the products less crunchy. To counter this effect, whey proteins can be texturized with starch to improve their interaction with other food components in a formulation, principally to increase extmdate expansion. In one successful application, between 25% and 35% of the flour was replaced with whey protein (Onwulata et al., 2001a,b). 

Allen et al. (2007) produced puffed snack foods with com starch and pregelatinized waxy starch, WPC and instantized WPC, and protein concentrations of 16%, 32%, and 40% and showed that the air cell size, extru-date expansion ratio, and water solubility index decreased proportionally as protein and com starch levels increased. Protein concentration significantly affected total soluble protein, water absorption index, and water-soluble carbohydrate. A covalent complex between amylase and protein formed in the presence of cornstarch, but protein-protein interactions appeared with the presence of low levels of pregelatinized waxy starch. 

In a qualitative way, colloids are stable when they are electrically charged (we will not consider here the stability of hydrophilic colloids - gelatine, starch, proteins, macromolecules, biocolloids - where stability may be enhanced by steric arrangements and the affinity of organic functional groups to water). In a physical model of colloid stability particle repulsion due to electrostatic interaction is counteracted by attraction due to van der Waal interaction. The repulsion energy depends on the surface potential and its decrease in the diffuse part of the double layer the decay of the potential with distance is a function of the ionic strength (Fig. 3.2c and Fig. 

In this study, we present evidence for the first time of a three-way interaction among starch, protein, and lipid that alters starch paste viscosity profiles. (Adapted from Zhang and Hamaker, 2003)... 

Zhang, G. Hamaker, B. R. AThree Component Interaction among Starch, Protein, and Free Fatty Acids Revealed by Pasting Profiles. J. Agric. Food Chem. 2003, 51, 2797-2800. 

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