PHYSICOCHEMICAL AND FUNCTIONAL-PROPERTIES OF WHEY-PROTEIN AS AFFECTEDBY LIMITED PAPAIN PROTEOLYSIS AND SELECTIVE ULTRAFILTRATION

Limited proteolysis of whey protein by papain at pH 6.5 and subsequent thermal unfolding at acidic pH weve studied and correlations between physico-functional (solubility, foaming, emulsifying) and physico-chem ical properties were determined. The optimal degree of hydrolysis (DH) for functionality was about 3.0%, characterized by a significant redu ction of aggregated whey protein present in commercial ultrafiltered w hey protein concentrates. From chromatographic and electrophoretic res ults it may by concluded that peptidic fragments ave derived from bovi ne serum albumin and molecular unfolded beta-lactoglobulin whereas alp ha-lactalbumin remained unaffected. Liberated peptidic fragments were found to support foaming but not emulsification as determined by a sel ective ultrafiltration. The beneficial effects of proteolytic and ther mal modification of proteins can be maximized with each protein requir ing a particular protease to develop a desirable functionality at well -defined DH.