Effect of High Hydrostatic Pressure and Thermal Treatment on Quality of Fermented Pomegranate Juice

The aim of the present study was to evaluate the effect of high hydrostatic pressure(HHP,600 MPa/10 min)and thermal processing(TP,65 ℃/20 min)on physicochemical indexes of fermented pomegranate juices during storage for 30 days at 4 ℃.The results showed that,the yeasts and molds were not detected,and the counts of total aerobic bacteria were less than 10 CFU/mL after HHP and TP treatments immediately,and the microbial safety(≤100 CFU/mL)was ensured in HHP-treated and TP-treated samples during storage. The pH and total soluble solids(TSS)had no significant change(p>0.05)immediately after HHP and TP treatment and during storage. The titratable acidity(TA)had no significantly change(p>0.05)after HHP and TP processing,but decreased significantly(p<0.05)during storage. A greater retention of anthocyanins,total phenols,total flavonoids and antioxidant capacity were observed in HHP-treated samples immediately after processing. The content of anthocyanins,total phenols,total flavonoids and antioxidant capacity in HHP-treated and TP-treated juice decreased during storage. All HHP-treated samples showed a slight reduction in antioxidant capacity,anthocyanins and total phenols,but the TP-treated samples showed a slight reduction in total flavonoids. Compared with the control,both HHP and TP had little impact on the color of fermented pomegranate juice immediately after processing,while the color changed in TP-treated samples were higher than HHP-treated samples during storage. Conclusion:Compared with TP,HHP could better maintain the content of total phenol,total flavonoids,anthocyanins and antioxidant capacity.