PHYSICOCHEMICAL PROPERTIES OF S-ZONE AND BASE PROTEINS IN GLUTEN

Abstract

Some of the physicochemical properties (solubility, viscosity, sedimentation) and the amino acid composition of the isolated S-zone and base proteins from soft-wheat gluten were studied. The S-zone proteins are homogeneous in size, of low molecular weight (about 20,000), and high intrinsic viscosity in buffer of pH 3,5, having stable structures whose unique solubility properties are related to their atypical amino acid content. The base protein molecules exist in a more folded conformation, having the properties of globular protein molecules. The protein–protein interactions, aggregation, and unfolding conformation of S-zone proteins are major contributing factors at neutral pH to the rheological properties of wheat flour, such as viscosity, elasticity, and cohesiveness.