Antioxidant properties of Klunzinger's mullet (Liza klunzingeri) protein hydrolysates prepared with enzymatic hydrolysis using a commercial protease and microbial hydrolysis with Bacillus licheniformis

Antioxidant activity of Klunzinger's mullet (Liza klunzingeri) muscle hydrolysates obtained using Bacillus licheniformis fermentation and enzymatic hydrolysis was determined. Hydrolysates obtained after 6 days of fermentation with B. licheniformis showed the highest free radical scavenging activity, metal chelating ability and ferric reducing antioxidant power (FRAP) (P <= 0.05). Microbial fermentation led to a higher percentage of small peptides and higher solubility compared with Alcalase hydrolysis (P <= 0.05). Hydrolysates showing the highest antioxidant properties attenuated serum, liver, and kidney oxidative stress biomarkers in male Wister rats stressed by carbon tetrachloride (P <= 0.05). At 300 mg/kg oral administration, hydrolysates increased serum, renal, and hepatic total antioxidant capacity (TAC) (P <= 0.05) and reduced their elevated levels of malondialdehyde (MDA), nitric oxide (NO center dot), and serum liver enzymes (AST, ALP, and ALT) (P <= 0.05). The hydrolysates were able to ameliorate hepatic damage by reducing necrosis, fatty changes, and inflammation. Results showed the antioxidant and hepato-toxic protective activities of Klunzinger's mullet muscle hydrolysates obtained using microbial fermentation, which may, therefore, potentially be considered as a functional food ingredient.

Automated summary

The antioxidant activity of Klunzinger's mullet muscle hydrolysates obtained through Bacillus licheniformis fermentation and enzymatic hydrolysis was determined, showing higher free radical scavenging activity and metal chelating ability. These hydrolysates also exhibited a reduction in oxidative stress biomarkers in rats and increased total antioxidant capacity while decreasing malondialdehyde, nitric oxide, and liver enzyme levels.