Study of the inactivation of Escherichia coli and pectin methylesterase in mango nectar under selected high hydrostatic pressure treatments
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High hydrostatic pressure (HHP) was applied to fresh mango nectar (FMN) and sterilized mango nectar (SMN) to inactivate Escherichia coli and pectin methylesterase (PME). Pressure was applied at 275, 345 and 414MPa. The come-up time (CUT) as well as 1, 2 and 4min of treatment times were applied at the selected pressure to evaluate the inactivation effect on E. coli and PME. Total plate counts (TPC) were also evaluated in FMN. Results showed that mesophiles are inactivated in FMN to an important degree (up to 4 log) only with the CUT; the highest inactivation for mesophiles (7 log) was reported at 414MPa after 4min. Meanwhile, for E. coli 345 and 414MPa after 2 and 1min, respectively, were able to inactivate all viable cells in FMN. However, in SMN after 4min at 275MPa all cells of E. coli were also inactivated, showing the protective effect of the media between FMN and SMN. The PME showed its resistance to be inactivated with high pressure, showing the highest decrease in enzymatic activity (45%) after 4min at 345MPa but with an important activation at the highest pressure (414MPa). © 2011 The Author(s).