Effects of composite biological preservative containing Paenibacillus polymyxa on quality changes of litchi

Paenibacillus polymyxa was used for preservation of Guiwei litchi after harvest. P. polymyxa，0.3 g/L natamycin and 1% sodium lactate were compounded into biological preservative DN004. Litchi fruits were soaked into DN004 and preservative attached to fruits. Meanwhile，water was treated as negative control and sportak was treated as positive control. All litchi were stored at 29-33℃，RH 95%-98%. The results of fruit quality showed that， compared with the control group，in DN004 group，the browning index decreased by 2.7，good fruit rate increased by 31%，weight loss rate decreased by 0.09%，anthocyanin content increased by 0.08 mg/g·FW，vitamin C content increased by 1.3 mg/100 mL after four days of storage. After storage for 7 days，titration acid increased by 0.049%， sugar degree increased by 0.9%. These data indicated that preservative could not only inhibit the respiration of fruit， delay the decline of fruit nutrition，but also decrease the lost of water，decrease commodity rate and extend shelf life.