Functional properties of ovine whey protein concentrates produced by membrane technology after clarification of cheese manufacture by-products

Functionality (solubility, emulsifying and foaming properties) of ovine cheese whey and deproteinized whey (Sorelho) protein concentrates was evaluated. Both by-products of ovine cheese manufacture were clarified by thermocalcic precipitation and microfiltration using two pore size membranes (0.65 and 0.20 mum). Next, they were ultrafiltrated/diafiltrated, and then, the liophilization of the corresponding retentates was carried out. The functionality of these powders, as well as that of untreated ultrafiltrated whey protein concentrate (WPC) and microfiltration retentates powders, was evaluated. The clarification treatment increased solubility of the WPC produced from ovine whey and deproteinized ovine whey. Moreover, these products had foaming properties, whereas conventional WPC and microfiltration retentate powders (MFRP) were unable to produce foams. The whey product obtained after clarification using a 0.65 mum microfiltration membrane had the best foaming properties. The clarification treatment did not significantly increase emulsifying activity and stability, except for the Sorelho product obtained using a 0.65 mum membrane. MFRP from ovine whey and Sorelho, the by-products of the clarification procedure, showed similar solubility and higher emulsifying activity than conventional WPC, although their emulsion stability was lower. The clarification procedure studied, particularly when a 0.65 mum microfiltration membrane was used, improved some functional properties of the whey and Sorelho protein concentrates, and also generated microfiltration retentates for potential use in food manufacturing. (C) 2003 Elsevier Ltd. All rights reserved.