In vitro and in vivo antioxidant activities of soy protein isolate fermented with Bacillus subtilis natto

The Bacillus subtilis natto fermented soy protein isolate (FSPI) exhibited concentration-dependent scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS+·) and hydroxyl (·OH) free-radicals. In addition, FSPI administration significantly increased superoxide dismutase activity in mice liver and serum by 20.2% and 86.2%, and suppressed the production of malondialdehyde by 51.3% and 35.1%, respectively, compared to high-fat control (HFC) group. Notably, the movement of mice treated with FSPI was livelier and more active, and its weight gain was significantly lower than that of both NC and HFC groups. The production and accumulation of perirenal fat was also significantly inhibited by FSPI, however, no significant difference in TG and TC levels were observed between FSPI and HFC groups. The results revealed the great potential of FSPI applying in the development of health food or sports food.