Abstract
Enzymatically modified proteins produced from gelatin by papain-catalyzed incorporation of leucine hexyl ester and leucine dodecyl ester, designated as EMG-6 and EMG-12, respectively, were investigated for their surface properties. Both EMG-6 and EMG-12 had critical micelle concentrations of 0.1-0.2% and 0.02-0.04%, respectively, reducing the surface tension of water as rapidly as synthetic surfactants, while bovine serum albumin, casein and gelatin hydrolysate used as controls induced much slower rates of reduction in the surface tension. Application of the Gibbs adsorption equation gave area requirements of 77A2 molecule and 48A2 molecule for EMG-6 and EMG-12, respectively. Functional properties such as emulsifying activity index, emulsion viscosity, emulsion stability, whippability and foam stability were evaluated, with the results that these parameters for EMG-6 and EMG-12 were not greatly influenced by pH of the aqueous medium studied.
