Bio-preservation of longan fruits by complex preservative with Leuconostoc mesenteroides dgnkzx002

To investigate the preservation effects of lactic acid bacteria on Longan fruit（Dimocarpus longan Lour. cv. Shixia，Dongfeng）and to develop a complex bio-preservative agent as an alternative to chemicals，this paper optimized the ingredients of the complex bio-preservative agent by single factor experiments and L9（34）orthogonal design. Results indicated that L. mesenteroides had extremely significant influence on SOD activity in fruit peel，while 1.5% sodium lactate had a significant impact and the effect of 0.1% chitosan + 2% citric acid was minimun. The complex bio-preservative agent with 1.72×107 CFU/mL Leuconostoc mesenteroides dgnkzx002 +（0.1% chitosan + 2% citric acid）+1.5% sodium lactate had the most stable preservative effects on longan fruits. Results showed that total soluble solids（TSS）and vitamin C content of longan fruits treated with the complex bio-preservative agent decreased by 16%，21.22%，respectively，had significant differences with control. And the activity of PPO and POD in fruit peel were 40 and 565 U/min·g，lower than 122，1 920 U/min·g in control group.