Protein gelation

Belyakova, L.E., Antipova, A.S., Semenova, M.G., Dickinson, E., Matia-Merino, L., Tsapkina, E.N. (2003). Effect of sucrose on molecular and interaction parameters of sodium caseinate in aqueous solution relationship to protein gelation. Colloids and Surfaces B Biointerfaces, 31, 31 46. 

Gosal, W.S., Ross-Murphy, S.B. (2000). Globular protein gelation. Current Opinion in Colloid and Interface Science, 5, 188-194. 

Formation of protein gel structures can occur under conditions which disrupt the native protein structure provided that the protein concentration, thermodynamic conditions and other conditions are optimal for the formation of the tertiary matrix. The most Important food processing techniques relative to protein gelation Involve divalent cations (calcium) and/or heat treatment. 

Because of the dependence of sulfhydryl and disulfide reactions on heat treatment. It would be expected that their Involvement In protein gelation would depend greatly on gel formation conditions. For example, Catslmpoolas and Meyer (7) have suggested that disulfides play only a minor role In the progel to gel transformation In soybean globulins. In more Irreversible soy protein gelation processes, disulfide bridging may be Involved In... 

Nonprotein Components. More Information Is needed on the effects of proteln-llpld and protein-carbohydrate Interactions on protein gelation reactions. Effects of proteln-llpld Interaction on soy protein gelation have been partially characterized (24). 

Schmidt, R. H., Illingworth, B. L., Deng, J. C. and Cornell, J. A. 1979. Multiple regression and response surface analysis of the effects of calcium chloride and crysteine on heat-induced whey protein gelation. J. Agr. Food Chem. 27, 529-532. 

Protein gelation is induced by many factors such as temperature, pH, or additives. Protein molecules in a medium become reactive under appropriate conditions and, at a certain probability, will stick to one another upon collision. The resultant aggregate diffuses and forms larger aggregates by linking to other molecules or ag-... 

Auty, M.A.E., Fenelon, M.A., Guinee, T.P., Mullins, C., Mulvihill, D.M. 1999. Dynamic confocal scanning laser microscopy methods for studying milk protein gelation and cheese melting. Scanning 21, 299-304. 

A few studies have also reported on the effects of non-gelling neutral polysaccharides on whey protein gelation (Olsson et al., 2000, 2002 Monteiro et al., 2005 Tavares et al., 2005), revealing interesting relationships between the microstructure of the biphasic mixed networks and the observed viscoelastic behavior and pointing out the importance of the structural characteristics of the polysaccharide. 

Christ, D., Takeuchi, K. P, and Cxmha, R. L. 2005. Effect of sucrose addition and heat treatment on egg albumen protein gelation. J. Food Sci. 70(3) E230-E238. 

Tavares, C., Monteiro, S. R., Moreno, N., and Lopes da Silva, J. A. 2005. Does the branching degree of galactomannans influences their effect on whey protein gelation Colloids and Surfaces A. Physicochemical and Engineering Aspects, pp. 270-271 213-219. 

Unfortunately for most substances, an accurate knowledge of gel concentration is not available, and only order of magnitude estimates can be gained from the literature.101 Protein gelation, for instance, is thought to occur at concentration levels ranging from 20% to 40% by weight. Criteria need to be developed in order to experimentally detect enzyme gel build-up. 

Raghavan SR, Douglas JF (2012) The conundrum of gel formation by molecular nanofibers, wormlike micelles, and filamentous proteins gelation without cross-links Soft Matter 8 8539-8546... 

Fig. 19. Linear association of essentially spherical colloid particles which occurs in globular-protein gelation under conditions resulting in high net charge on the molecules.

Gelation in polymers may be brought about in several ways temperature changes, particularly important in protein gelation formation polymerization with cross-links phase separation in block copolymers ionomer formation or even crystallization. Such materials are usually thermoreversible for physical cross-links, or thermoset through the advent of chemical cross-Unks. Of course, there must be at least two cross-link sites per chain to induce gelation. A major... 

Aside from the obvious nutritional aspects, one of the most important properties of proteins, from a food processing point of view, is the ability to form gels. Protein gelation is a subtle combination of denaturation, dissociation/association reactions and aggregation, for which many different models have been proposed. So, for example, a simple general proposal for the heat-induced gel formation in small globular proteins is [74]... 

DSC has been carried out on a very wide range of proteins however, as in the case of fats, where the value of DSC-derived information was increased enormously by the complementary technique of X-ray diffraction, mainstream rheological measurements which categorise the gel behaviour are essential for even a rudimentary understanding of protein gelation. Nevertheless, the thermal properties of the processes involved in gelation can provide important thermodynamic information. 

The presence of small amounts of soluble wheat proteins in a mixture with salt-soluble meat proteins (SSMP) was capable of trebling the elastic modulus, compared with a pure SSMP gel [115]. This study highlights the inadequacy of DSC as a monitor of protein gelation properties. Despite the fact that no transitions were observed over 20-120°C by DSC, a weak gel was formed. Further, strong elastic gels were formed upon more severe treatment at 120°C. 

Protein aggregation during food preparation plays a significant role in structure fonnation of many gel-type or emulsion-type products [239]. Ferry [240] described protein gelation as the result of structure unfolding that exposes reactive sites, intermolecular aggregation, and eventual formation of infinite, crosslinked gel networks As the conformation of proteins is modified under the influence of heat, protein-protein interactions become more prevalent with formation of covalent and non covalent bonds. Covalently bonded proteins may be considered crosslinked different protein molecules can stick together or protein molecules can bind non protein components [241]. 

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