Determination of Functionalities of Proteins and Their Corresponding Hydrolysates from Brewers’ Spent Grain

It is well-recognized that the functional properties of proteins and peptides in the food industry not only determine the quality of some food products but also address consumer demands for healthier, safer, and more sustainable food options. Therefore, in this study, functional properties including water-holding capacity, oil-binding capacity, heat stability, turbidity, dispersibility, emulsifying and foaming properties of brewers’ spent grain proteins (BSGP) and their associated hydrolysates were evaluated in the pH range from 2.0 to 12.0. Additionally, the effect of enzymatic hydrolysis using Alcalase and â±­-chymotrypsin on these properties was also determined. Notably, the hydrolysis of intact BSGP significantly improved both water and oil-binding capacity. Similarly, enzymatic hydrolyzation was found to present a positive impact on the heat stability of all tested samples, with the â±­-chymotrypsin hydrolysate from fermented BSGP showing exceptional thermal stability at 140 °C across the entire pH range even after 300 min heating. Turbidity and dispersibility profiles remained consistent across all samples and pH 4 seemed to be a critical point influencing sample behavior. Alcalase hydrolysates displayed an improved emulsion activity index (EAI) with the highest observed EAI of 28.30 ± 0.79 m2 g−1 attained for the Alcalase hydrolysates derived from fermented BSGP at pH 12.0. The maximum foaming capacity (FC) and foaming stability (FS) were observed for all samples at pH 12.0 while hydrolysis significantly reduced the FC and FS. Overall, fermented intact protein, depending on suitable pH, exhibited beneficial functional properties, with potential applications in various food industries.