COPRECIPITATION OF CHEESE WHEY WITH SOYBEAN AND COTTONSEED PROTEINS USING ACID AND HEAT TREATMENT

Abstract

ABSTRACTSoybean‐ and cottonseed‐whey protein coprecipitate isolates (SIW and CIW) and coprecipitate concentrates (SCW and CCW) were all prepared using heat treatment (95°C, 15 min) at acidic pH (4.6). Soybean and cottonseed protein isolates (SI and CI) and concentrates (SC and CC) and whey protein concentrate (WC) were also prepared under similar conditions for comparison with the coprecipitates. In general, the coprecipitation resulted in acidulant savings (7–9% for SIW and CIW, 51–68% for SCW and CCW), higher nitrogen yields (24–29% for SIW and SCW, 10–17% for CIW and CCW), higher protein scores, lighter color, slightly higher solubility, lower water and fat absorption and emulsifying capacities compared with separate precipitation of the oil‐seed proteins. The whipping properties decreased in the coprecipitate isolate but increased in the coprecipitate concentrate of soybean and cottonseed. Compared with a commercial soy isolate, all coprecipitates had lower solubility, emulsifying and whipping capacities but equivalent water and fat absorption capacities.