Effect prolamins

A response surface model of the effects of HA protein concentration (gliadin, the wheat prolamin), HA polyphenol concentration (tannic acid, TA), alcohol, and pH on the amount of haze formed was constructed using a buffer model system (Siebert et al., 1996a). Figure 2.12 shows the effects of protein and polyphenol on haze predicted by the model at fixed levels of pH and alcohol. The model indicates that as protein increases at fixed polyphenol levels, the haze rises to a point and then starts to decline. Similarly, when polyphenol increases at a fixed protein level, the haze increases to a maximum and then declines. 

Rumbo, M., Chirdo, F.G., Fossati, C.A., and Anon, M.C. 2001. Analysis of the effects of heat treatment on gliadin immunochemical quantification using a panel of anti-prolamin antibodies. JAgric Food Chem 49(12) 5719-5726. 

Glutaminases can be applied, but these enzymes do not affect asparagine residues as substrate (Yong et al., 2004). In case of gluten proteins, there exists another restriction prolamines are insoluble in water solvents, while ethanol solvents cause enzyme inactivation. The application of ion exchange carriers seems to be the most convenient method with the smallest side effects (Kumagai et al., 2002). 

Chemical antagonists simply bind to the active drug and inactivate lue.g. prolamine abolishe.s Ihe anticoagulant effect of heparin (Chapter 19). 

Wheat protein fractionation by the Osborne method provides prolamins and glutelins in a ratio of 1 1. Both fractions, in hydrated form, have different effects on the rheological characteristics of dough prolamins are responsible, preferentially, for viscosity, and glutelins for dough strength and elasticity. 

Globular proteins are soluble in polar solvents such as water and in aqueous solutions of acids and bases. Structural fibrous proteins are insoluble in water. Prolamins also dissolve in less polar solvents such as ethanol. In addition to the protein structure, solubility depends on the relative permittivity of the solvent, the pH value of the solution (the minimum solubility is at, or in the vicinity of, the isoelectric point), its ionic strength (a low concentration of salt increases the solubility by the salting-in effect, higher concentrations ofsalt reduces the solubility by the salting-out effect see Section 7.6.3.2.3), temperature and other factors. 

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