Optimization of the alcalase and trypsin hydrolysis conditions of an isolated protein from Scenedesmus obliquus microalgae and characterization of its functional properties
Motahharesadat Amiri, Seyed Ebrahim Hosseini, Gholamhassan Asadi, Babak Khayambashi
Abstract
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.