Production of Okara Protein Hydrolysate With Bromelain–Papain Combination and Characterization of Physicochemical and Functional Properties

Okara is a byproduct of tofu production that contains a large amount of protein but is still underutilized. Enzymatic hydrolysis is carried out to break down okara protein into bioactive peptides with potential functional properties. This study aims to determine the optimal conditions for enzymatic hydrolysis of okara using a combination of bromelain and papain enzymes with various enzyme concentrations and hydrolysis times and to characterize the physicochemical and functional properties of the resulting protein hydrolysate. The best hydrolysis conditions were 12% bromelain, 9% papain, and a hydrolysis time of 153.33 min, which experimentally produced a degree of hydrolysis (DH) of 8.87% and antioxidant activity of 14.78%. When compared to the control, DH was 1.78% and antioxidant activity was 4.06%. The results of physicochemical characterization showed that in the okara supernatant protein hydrolysate powder with a yield of 19.76%, many peptides were identified as 98 peptides, water holding capacity (WHC) −0.56 g/g, oil holding capacity (OHC) 1.77 g/g, water solubility (WS) 75.30%, emulsifying activity index (EAI) 20.91 m 2 /g, emulsifying stability index (ESI) 26.70 min, foaming capacity (FC) 20%, and foaming stability (FS) 9.33%. While in the control without hydrolysis, the yield was 5.87%, many peptides were identified as 90 peptides, WHC 1.14 g/g, OHC 1.15 g/g, WS 50.03%, EAI 9.39 m 2 /g, ESI 37.46 min, FAI 9.11%, and foaming stability index (FSI) 8%. Practical Applications The enzymatic hydrolysate of okara protein produced has the potential to be applied in the development of functional foods.