Effect of Ultra High Pressure Treatment on Storage and Quality Characteristics of Lycium ruthenicum Murr Juice

In order to develop new technologies for Lycium ruthenicum Murr juice processing,the juice of Lycium ruthenicum Murr treated by ultra-high pressure treatment(300,400,500 MPa/10 min) and pasteurization(75℃,15 min) were compared on microorganisms,main endogenous enzyme activities,active substances,and antioxidant capacity. The changes of these physicochemical indexes were also compared during storage period(4 and 37℃,40 d). The results showed that high-pressure treatment above 200 MPa and pasteurization could effectively kill yeasts and molds. High-pressure treatment above 300 MPa could reduce the total number of colonies to less than one logarithm. High-pressure treatment at 300 MPa could reduce POD enzyme activity to 17.81 U/mL,but could not significantly reduce PPO enzyme activity. Above 400 MPa and pasteurization could reduce POD enzyme and PPO enzyme activity to 0.5 U/mL. With the conditions of ultrahigh pressure treatment of 300,400,and 500 MPa,the contents of polyphenols were 87.10,87.11,86.92 mg/100 g,and total polysaccharide contents were 61.54,61.04,60.97 mg/mL,and anthocyanin contents were 2.62,2.56,2.58 mg/mL in juice under ultra-high pressure treatment. The DPPH free radical scavenging rates of Lycium ruthenicum Murr juice by ultra-high pressure treatment were 86.82%,87.40%and 86.60%,which were higher than 82.17%. The abilities reduced ferrous ions of Lycium ruthenicum Murr juice from ultra-high pressure treatment were 15.74,16.15,and 15.95 μg/100 mL DW,which were higher than those of pasteurization until the end of storage. The ultra-high pressure treatment could effectively inactivate microorganisms and inactivate enzymes,and protect the active substances from destruction to ensure the antioxidant capacity of Lycium ruthenicum Murr juice,so that the Lycium ruthenicum Murr juice would have a good storage quality.