Change of Components and Antioxidant Activity of Banana Enzymes during Fermentation Process

Bananas as raw material was fermented by natural,yeasts or Lactobacillus plantarum to produce banana enzymes. The antioxidant capacity and compounds of the banana enzymes during fermentation were determined. The results showed that,as fermentation time extended,the DPPH free radical scavenging ability of banana enzymes fermented by natural,fermentation and banana enzymes yeast or Lactobacillus plantarum increased,and the highest clearance rate reached 48.97%,79.54% and 69.79%,respectively. The scavenging ability of hydroxyl radicals also increased,and the highest scavenging rates were 37.68%,49.97% and 45.38%,respectively. The activity of SOD and alkaline protease of banana enzymes inoculated with yeast and Lactobacillus plantum increased gradually with fermentation time extending. After reaching the maximum value,its growth reached a relatively stable state,while the naturally fermented banana enzyme showed a gradual weakening trend after reaching the maximum value. The highest SOD activity reached 89.5,86.79 and 48.35 U/mL,respectively. The highest enzyme activities of proteases were 67.90,66.58 and 32.28 U/g,respectively. The polysaccharides content of banana enzymes fermented with yeast or Lactobacillus plantarum increased and then stabilized with the increasing of fermentation time. The maximum content were 20.45 and 19.9 mg/g. The naturally fermented banana enzymes showed a gradual decline after reaching a maximum of 17.31 mg/g.The indexes of naturally fermented banana enzymes were lower than the banana enzymes fermented with yeast or Lactobacillus plantarum. And experimental results showed that the index of the yeast banana enzymes were higher than that of Lactobacillus plantarum fermented banana enzyme,but the difference was not obvious,so both kinds of microbiology could be used in the fermentation of banana enzymes.