BACKGROUND

Spirulina platensis (S. platensis) is recognized as one of the most nutritious foods containing a high protein content up to 70%. Meanwhile, the interest in using natural protein resource to develop bio‐active peptides is steadily increasing. Therefore, this study released the bio‐active peptides from S. platensis by enzymatic hydrolysis using pepsin (1:3000 U/g), and their amino acid sequences were determined by de novo sequencing. On this basis, the antioxidant activities of synthesized bio‐active peptides were comprehensively evaluated by 2,2′‐azinobis‐3‐ethylbenzothiazolin‐6‐sulfonic acid (ABTS) assay, 1,1‐diphenyl‐2‐picryhydrazyl (DPPH) assay, and cell hemolysis assay induced by 2,2′‐azobis‐(2‐amidino‐propane) dihydrochloride (AAPH).

RESULTS

The degree of hydrolysis and recovery percentage of pepsin hydrolysis was 172 g kg^‐1 and 825 g kg^‐1, respectively, and peptides containing m/z and the relative intensity of FFEFF (P1, m/z 736.4, 80%), EYFDALA (P2, m/z 828.4, 18.5%) and VTAPAASVAL (P3, m/z 899.5, 17.3%) were purified and identified. Thereinto, P2 possessed an excellent radical scavenging activity than P1, P3 and Vitamin c (Vc), which was contributed by its high β‐sheet conformation and specific amino acid compositions. Moreover, P2 significantly attenuated AAPH‐induced oxidative hemolysis of erythrocytes and protected the erythrocytes, because it reduced the formation of malondialdehyde and increased the enzyme activities of superoxide dismutase, catalase and glutathione peroxidase in erythrocytes.

CONCLUSION

This study provided insights into the potential antioxidant function of the synthesized peptides originated from the bio‐active peptides of S. platensis proteins, which would contribute to the development of natural antioxidant from new protein resources.