Abstract: The preparation of fermented fish broth with high antioxidant activity from macheral meat with food-grade Bacillus subtilis was investigated in the present study. The results of one-factor-at-a-time experiments showed that highly antioxidant fermented fish broth was obtained under the fermentation conditions: medium volume of 50 mL or 100 mL in 250 mL shake flasks, glucose concentration of 2%, fish meat-to-water ratio of 1:(1－2 )(m/V), and rotation speed of 150 r/min. It was also found that glucose concentraiton, medium volume in 250 mL shake flasks and fish meat-to-water ratio were main parameters that influence the production of antioxidant ingredients. Using response surface methdology based on a Box-Behnken experimental design, the main fermentation parameters were optimized to be 3.98%, 96.02 mL/250 mL and 1:1.60(m/V), respectively. The fermented fish broth obtained under these conditions exhibited a DPPH radical scavenging rate of 94.52%.

Key words: fish protein, antioxidant factors, Bacillus subtilis, fermented broth, antioxidant activity