| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4366519 | International Journal of Food Microbiology | 2015 | 11 Pages |
•Effect of HPP on natural microbiota in pineapple puree was determined.•Microflorae were aerobic mesophiles, psychrotrophs, yeast & mold, coliforms & LAB.•The Weibull model fitted better to the survivor populations during isobaric period.•The yeast and mold group was the most baroresistant present in the sample.•An empirical model was developed for death rate constant as a function of P and T.
High pressure inactivation of natural microbiota viz. aerobic mesophiles (AM), psychrotrophs (PC), yeasts and molds (YM), total coliforms (TC) and lactic acid bacteria (LAB) in pineapple puree was studied within the experimental domain of 0.1–600 MPa and 30–50 °C with a treatment time up to 20 min. A complete destruction of yeasts and molds was obtained at 500 MPa/50 °C/15 min; whereas no counts were detected for TC and LAB at 300 MPa/30 °C/15 min. A maximum of two log cycle reductions was obtained for YM during pulse pressurization at the severe process intensity of 600 MPa/50 °C/20 min. The Weibull model clearly described the non-linearity of the survival curves during the isobaric period. The tailing effect, as confirmed by the shape parameter (β) of the survival curve, was obtained in case of YM (β < 1); whereas a shouldering effect (β > 1) was observed for the other microbial groups. Analogous to thermal death kinetics, the activation energy (Ea, kJ·mol− 1) and the activation volume (Va, mL·mol− 1) values were computed further to describe the temperature and pressure dependencies of the scale parameter (δ, min), respectively. A higher δ value was obtained for each microbe at a lower temperature and it decreased with an increase in pressure. A secondary kinetic model was developed describing the inactivation rate (k, min− 1) as a function of pressure (P, MPa) and temperature (T, K) including the dependencies of Ea and Va on P and T, respectively.
