Optimizing and Characterization of Soybean Oil Seed Cake Protein Hydrolysis: In Vitro Analysis

The study aimed to optimize the hydrolysis process of soybean oil seeds to produce protein hydrolysate powder with enhanced functional properties. The proximate analysis revealed that the hydrolysate had a significantly higher protein content (60.33%) compared to the original oil seed cake (46.26%). Using response surface methodology, the optimum condition of hydrolysis was found to be at pH 8 with an enzyme concentration of 0.3%. Under these conditions, the hydrolysate showed high antioxidant activity of (45.80%), total phenolic content of (1.80 mg GAE/g), and total flavonoid content of (0.54 mg QE/g). The techno-functional properties of the optimized hydrolysate powder, including bulk density (0.51 g/mL), tapped density (0.66 g/mL), foaming capacity (22%), foam stability (50.4%), water absorption index (2.28 g/g), water solubility (59.66%), and oil absorption capacity (1.34 g/g) were found to be superior compared to other protein hydrolysates from literature. Characterization by FTIR revealed the presence of alcohol, alkane, amine, fluoro, and halo compounds, while XRD indicated a semi-crystalline nature. SEM analysis showed a microporous, broken, and brittle morphology. The hydrolysate also exhibited promising bioactivities, with 40.33% lipase inhibition, 53.47% amylase inhibition, and prolonged glucose retention time up to 240 min in an in vitro model. These results demonstrate the potential of the optimized soybean oil seed cake protein hydrolysate as a value-added product for applications in food, pharmaceutical, and biotechnology industries.