Effect of High Hydrostatic Pressure and High Temperature Short Time Treatment on the Microbial and Quality Characteristics of Green Compound Fruit and Vegetable Juice

Through the sensory evaluation, comprehensive basic physical and chemical indicators were used to obtain a better formula of green compound fruit and vegetable juice, and high hydrostatic pressure (HHP) and high temperature short time (HTST, 86℃/15 s) treatment were applied in compound fruit and vegetable juice for inactivation of microorganism. The changes of qualities of compound fruit and vegetable juice during storage (4℃) were investigated. After the HHP treatment of 600 MPa/5 min and the HTST treatment of 86℃/15 s, the number of total aerobic bacteria was decreased from 5.18 lg CFU/mL to 1.07 lg CFU/mL and 1.11 lg CFU/mL. The yeast and molds, lactobacillus and psychrophilic bacteria were not detected. The total phenolic content of the juice treated by HHP was 43.645 μg/mL, which was significantly higher than that of HTST green compound fruit and vegetable juice. The indexes such as content of total phenol, suspension stability, color and antioxidant activity in HHP treated juice were better preserved than those of HTST treated juice. During the storage of 15 days at 4℃, the microorganisms did not exceed the national hygienic standard. The suspension stability, color, the total phenol content and antioxidant activity were decreased in both of HHP treated juice and HTST-treated juice, but the indexes of HHP group were superior to that of pasteurized group.