INTERFACIAL AND EMULSIFYING PROPERTIES OF WHEY PEPTIDE FRACTIONS OBTAINED WITH A 2-STEP ULTRAFILTRATION PROCESS

Interfacial and emulsifying properties of whey protein concentrate (WPC), heat-treated WPC (90-degrees-C, pH 2.5, 10 min), and their tryptic or chymotryptic peptide fractions obtained by ultrafiltration were measured in conditions similar to a salad dressing emulsion (pH 4.0; mu = 0.6). The rate of adsorption of protein components at the air/water interface as well as emulsifying capacity (EC) was determined. The type of enzyme and UF separation of small components from the hydrolysates were significant treatments for both parameters studied. A correlation was found between the square root of the rate of adsorption and EC (r = 0.98, P < 0.0001). A combination of heat treatment, tryptic hydrolysis, and UF separation of small components from the hydrolysate gave a fraction having better interfacial properties than WPC, which may lead to improved emulsifying properties for food applications.