SOME PHYSICOCHEMICAL AND INTERFACIAL PROPERTIES OF NATIVE AND ACETYLATED LEGUMIN FROM FABA BEANS (VICIA-FABA L)

The influence of acetylation on adsorption kinetics, film compression behavior (air/water), emulsifying properties (n-decane/water emulsions ), and conformation of legumin from faba beans was studied. These meas urements involved the Wilhelmy plate method, film balance, turbidity m easurements, centrifugation, and size exclusion and reversed phase HPL C, UV absorption, and fluorescence probes. While distinct changes in p hysicochemical properties only occurred above a ''critical degree of m odification'' (approximately 60%) e.g. dissociation and denaturation o f the molecule and increased surface hydrophobicity, emulsifying prope rty parameters linearly improved with acetylation as indicated by an i ncrease in the emulsifying activity index of the legumin, improved coa lescence stability of the emulsions, and decreased droplet size distri bution and protein load of the oil droplets. The measured contact angl e due to adsorption of legumin at the Wilhelmy plate distinctly influe nced parameters of the Gibbs adsorption isotherms. A correlation betwe en the critical association concentration and the emulsifying activity of the protein samples was also found.