Effects of rice bran protein hydrolysates on the physicochemical stability of oil-in-water emulsions.

Isolation of proteins from rice bran was studied, comparing alkaline- and carbohydrase-aided extraction. It was found that protein extractability could be effectively improved using carbohydrases (Viscozyme L and α-amylase), especially when mechanical force was incorporated. Then, rice bran protein hydrolysates (RBPH) were prepared at various degrees of hydrolysis (DH), and employed to stabilize soybean O/W emulsion. Improved colloidal stability of the emulsions could be achieved using RBPH, especially at higher DH level, as indicated by an increase in the emulsifying activity index and better long-term dispersibility. The present work novelty suggested the efficiency of RBPH to improve oxidative stability of the emulsions. The most potent antioxidant activity was exhibited by RBPH with DH of 6.4 and 7.6%. With their efficiency to promote physicochemical stability of the emulsions, RBPH might be potently employed as a natural additive in emulsified food products, which is significant to value addition of rice bran for further industrial application.