Effect of Ultra-high Pressure Sterilization and Pasteurization on the Quality of Passion Fruit Juice during Storage

The effects of ultra-high pressure sterilization (UHP, 600 MPa/6 min) and pasteurization (80 ℃/30 s) on the total number of colonies, physical and chemical indexes, antioxidant activity, nutritional components and volatile components of passion fruit juice during storage were studied. The results showed that the passion fruit juice were commercially sterile under these two treatments. After the storage period, the total number of bacterial colonies of pasteurization and ultra-high pressure sterilization were less than 100 CFU/mL. Pasteurization significantly increased the total color difference of passion fruit juice (P<0.05) and was always higher than that of ultra-high pressure treatment, indicating that ultra-high pressure sterilization was more effective in maintain the color of passion fruit juice. Ultra-high pressure treatment had no significant effect on the soluble sugar, total acid and protein content of passion fruit juice (P>0.05). After the end of storage period, the contents of total phenols, vitamin C and total flavonoids in pasteurization juice was significantly lower than those in ultra-high pressure sterilization (P<0.05). The retention rates of volatile compounds esters, alcohols, ketones, aldehydes and alkenes in pasteurized juice were lower than that in ultra-high pressure treatment, and all retention rates were negatively correlated with storage period. In conclusion, traditional pasteurization can reduce the sensory quality and nutritional quality of passion fruit juice, and ultra-high pressure sterilization has obvious advantages in maintaining the quality of passion fruit juice.