Effect of bacillus amyloliquefaciens fermentation liquid on different types of peppers for biological control of postharvest A. alternate

Abstract: In order to understand the fresh-keeping effect of bacillus amylo-liquefaciens strain-L fermented liquid on the postharvest pepper, the different pepper varieties (the green pepper and red chilli) were treated with fermented filtrated liquor of bacillus amylo-liquefaciens isolated from chilli bell peppers pulp to study the preserve effects of peppers. The results indicated that the strain-L fermentation medium over a certain concentration had a good antibacterial effect on pepper pathogenic fungi (A.alternate) with the invitro tests. The invivo test results showed that even though the fresh-keeping effect of fermentation liquid was not as good as fresh-keeping effect of preservative liquid, but significantly better than the sterile water group. Comparing the different varieties of peppers, fresh-keeping effect of fermentation liquid on red chilli was better than that of green pepper, and the inhibition effect of invivo decreased compared with invitro inhibition effect.For the damage inoculation, strain-L fermentation medium has obvious antibacterial effect on the green pepper and red chilli, the decay rate of green pepper declined by 51.87% compared with sterile water treatment. The decay rate of the red chilli declined by 58.54% compared with sterile water. The preservation effect of strain-L fermentation medium on different varieties of pepper had significant difference during 24 d storage period by noninvasive inoculation. The results showed that the strain-L fermented liquid treatment can obviously decrease the decay rate of postharvest chili in the storage period, which was obviously superior to the sterile water group. After 24 d storage, the decay rates of green peppers treated with fermentation medium and preservation liquid were 37.5%, 32.50% respectively, decreased by 35% and 40% respectively compared to sterile water group. The decay rate of red chilli treated with fermentation medium and preservation liquid were 29.63%, 24.14% respectively, decreased by 34.19%, 28.70% respectively compared to sterile water group.The levels of decay rates were different for different varieties with fermentation medium treatment group and preservation liquid treatment. The decay rate of red chilli was lower than the green pepper by about 7.87% and 8.36% respectively. It showed no significant change among the different treatments. In the whole storage period, the strain-L reduced the decay rates; delayed the reduction of reducing sugar content; inhibited the loss of soluble solid content, soluble protein and the content of VC; maintained the stable color and quality structure. Strain-L fermentation liquor obtained the good storage effect in keeping the chili good commodity value, sensory quality and nutritional value. The research can provide a theoretical basis for biological prevention and technical methods for fresh-keeping of postharvest vegetables.