2014 Volume 20 Issue 6 Pages 1153-1164
“Sanhua” plums of 4 cultivars were processed into juice. Pretreatment including heat blanching (HB), microwave blanching (MB) and SO2 were studied on the inactivation of polyphenoloxidase (PPO), peroxidase (POD) and nutrition qualities. Enzymatic clarification, pasteurization and UHT were also investigated on nutrition qualities. Results showed that PPO and POD could be almost inactivated by HB (95°C − 5 min) and MB (700 W − 150 s). Pretreatments extracted more phytochemicals and antioxidant activity (AA) and MB produced higher effect than other two means. The high content of phytochemicals after pretreatment could correlate with the inactivation of PPO and POD. Clarification resulted in a better extraction of nutritional compounds. Pasteurization only slightly increased and UHT remained unchanged or slightly degraded the nutrition qualities. Significant loss of nutritional compounds was found during juicing process. Our findings are useful when evaluating health benefits of plum juice.
