Combined effects of acidification and high-pressure processing on microbial inactivation, bioactive compounds and antioxidant activity of liquorice root sherbet

Abstract

High Hydrostatic Pressure Processing (HPP) has gained more attention in the fruit and vegetable industry in recent years. In this study, the optimal acidification parameters (citric acid alone and combination with ascorbic acid at the pH range 3.0 to 4.5) were determined and the effect of HPP conditions (pressures 250-450 MPa and exposure times 1-5 min) on acidified liquorice root sherbet (ALRS) were investigated. Results showed that acidification of LRS by only citric acid had higher aroma and flavor scores. HP treatments were effective to reduce the yeast and mold (YM) count, total coliforms (TC), and inoculated pathogens (Escherichia coli ATCC 25922 and Salmonella Typhimurium ATCC 14028) in ALRS. Although acidification of LRS achieved a significant reduction in glycyrrhizic acid (GA) content, further treatment by HPP did not affect pH, the contents of total phenolic, total soluble solids, flavonoid, and GA or the antioxidant capacity of ALRS. Our results suggest that acidification and HPP treatments could be used to increase consumer acceptability and extend the shelf life of LRS.