Optimization of high pressure processing for microbial load reduction in Diospyros kaki 'Fuyu' pulp using response surface methodology.

Abstract

Diospyros kaki L., cv. Fuyu is a non-astringent seasonally available persimmon variety from New Zealand having short shelf life. Most of the current preservation techniques like pasteurization, spray drying etc. use high temperature for microbial inactivation, which results in quality reduction. In the present study, response surface methodology having Box-Behnken design used to explore the consequence of pressure (200-600MPa), time (5-15min) and temperature (20-45°C) for controlling microbial load in fruit pulp. A mathematical model created to envision the responses, and the R2 value indicated that the established model proved highly accurate in the prediction of response. The optimization process advocated non-thermal minimal processing of persimmon pulp by high pressure processing at low temperature 20°C, 400MPa pressure for 5min holding time for reducing total plate count and yeast mould count.