Antioxidant Activity of Peptides Derived from Enzymatic Digestion of Spirulina platensis Protein Extract by Different Proteases

One of the attractive sources of bioactive compounds is cyanobacteria and in particular, Chlorellavulgaris and Spirulinaplatensis. Enzymatic digestion of the Spirulinaprotein extract can result in bioactive peptides with diverse activities, including antioxidant function. This study aims to produce peptides with antioxidant properties after the enzymatic digestion of Spirulinaplatensisprotein extract using three enzymes: bacterial protease, pepsin, and papain. The protein extract from Spirulina platensiswas subjected to enzyme hydrolysis for 3 hours at 37°C (pH 7.4 for papain and bacterial protease and pH 5 for pepsin). The concentration of peptide fragments was evaluated to determine the yield of protein digestion. In order to measure the level of anti-oxidative potential of the hydrolysates, the DPPH assay was run. The results indicated that the bacterial protease led to the highest concentration of peptide fragments, while the hydrolysate obtained from pepsin digestion showed the most antioxidant activity (80%), mainly the peptides that have molecular weights less than 14 KDa. Consequently, pepsin can be a proper enzyme to produce antioxidant peptides from the protein extract of S. platensis. In conclusion, the results of the study confirmed that the products of enzymatic digestion by different enzymes have distinct features.