Stability, Yield and Chemical Properties of Soymilk Whey from Sprouted Soybeans (Glycine max) of Different Varieties

Abstract

Soymilk whey was produced from sprouted soybeans of three different varieties, namely Samsoy 1, Samsoy 2 and TGX 1937-Is. They were separately sprouted in batches for 6 h, 12 h, 24 h, 36 h and 48 h respectively. Each batch of the sprouted soybeans was used to produce soymilk. Each batch of soymilk was divided into two parts and one partwas treated with â-glucanase. Whey was produced from all soymilk samples by the addition of citric acid. The whey phase was allowed to separate by natural sedimentation or centrifugation. Soymilk whey was analyzed for volume yield, proximate composition, total solids (%TS) and gel electrophoresis (SDS-PAGE). Stability of concentrated sterilized(121oC, 15 min) whey samples were evaluated by observing the visible coagulation time (VCT). The soybean variety did not significantly (p>0.05) affect the volume yield. The volume of whey produced at pH 4.5 was significantly (p< 0.05) higher than those at other pH tested. At the same pH, the â-glucanase-treated soymilk from sprouted soybeans had the highest whey volume (89.07%), which was significant (p>0.05) compared to the acid-only treated (86.13%), and unsprouted (control) was 45.8%. The SDS-PAGE electrophoregram showed that most proteins in the controlsamples diminished after sprouting, leaving proteins of 20 Kda molecular weight. Protein contents of whey from different soybean varieties were not significantly (p>0.05) different but protein in the sprouted and â-glucanasetreated soymilk was about half of the control samples. The VCT of soymilk whey was > 7 months. These results suggest that development of soymilk whey for food and beverage production is feasible