Effect of mild-heat and high-pressure processing on banana pectin methylesterase: A kinetic study

Pectin methylesterase (PME) was extracted from bananas and purified by affinity chromatography. The thermal-high-pressure inactivation (at moderate temperature, 30-76degreesC, in combination with high pressure, 0.1-900 MPa) of PME was investigated in a model system at pH 7.0. Under these conditions, the stable fraction was not inactivated and isobaric-isothermal inactivation followed a fractional-conversion model. At lower pressure (less than or equal to300-400 MPa) and higher temperature (greater than or equal to64degreesC), an antagonistic effect of pressure and heat was observed. Third-degree polynomial models (derived from the thermodynamic model) were successfully used to describe the heat-pressure dependence of the inactivation rate constants.