Optimization of the alcalase and trypsin hydrolysis conditions of an isolated protein from Scenedesmus obliquus microalgae and characterization of its functional properties

This study focused on fine-tuning the enzymatic hydrolysis variables, specifically the duration and enzyme concentrations of alcalase and trypsin, for Scenedesmus obliquus protein using response surface methodology (RSM) with a central composite design (CCD). The aim was to characterize the amino acids, separate hydrolysates based on molecular weight, and assess functional activities such as antioxidant, emulsifying, fat-binding, and foaming capacities. After fractionating the hydrolysates, bioactivities were evaluated through standard assays. The optimal hydrolysis conditions—10.24 g/100 mL alcalase and 2.56 g/100 mL trypsin—yielded the highest protein extraction. Peptides smaller than 5 kDa demonstrated 80% DPPH inhibition and superior fat-binding capacity. Emulsifying capacity peaked at 112 m 2 /g for peptides under 10 kDa, and the highest foaming index was observed for peptides below 5 kDa. The application of RSM effectively optimized the hydrolysis of microalgal protein isolates for maximum efficiency, highlighting microalgae's potential as a sustainable source of functional ingredients. • The enzymatic hydrolysis of Scenedesmus obliquus microalgae protein were successfully optimized. • Peptides <5 kDa exhibited 80% DPPH• scavenging and the highest fat binding capacity. • Emulsifying capacity peaked at 112 m 2 /g for peptides <10 kDa. • Peptides <5 kDa have the highest foaming index, making them ideal for foam stability applications.