文摘
High hydrostatic pressure (HHP) processing was applied for inactivation of natural microorganisms, including total aerobic bacteria (TAB), and yeasts and molds (Y&M) in purple sweet potato nectar (PSPN). The pressurization rates were 60 and 120?MPa/min, the pressurization modes were stepwise and linear, the pressure-holding times were 2.5-5?min, and the pressure levels were 400-00?MPa. In all the experimental conditions, the Y&M in PSPN were not detected, the maximum reduction of TAB was greater than 4 log cycles, and the inactivation of TAB was closely related to the HHP parameters. The fast pressurization rate and linear pressurization mode enhanced the inactivation effect of HHP on TAB. With increasing the pressure level and pressure-holding times, the inactivation of TAB was also enhanced. The mathematical models were fitted to the inactivation kinetic data of TAB and fitness of these models was investigated; the Weibull and Biphasic model successfully fitted all the inactivation curves. Pressurization rate and mode had a significant impact on the parameters of the models.