Strawberry Pectin Methylesterase (PME): Purification, Characterization, Thermal and High-Pressure Inactivation

Pectin methylesterase (PME) was extracted from strawberries (Fragaria ananassa, cv Elsanta) and purified by affinity chromatography on a CNBr-Sepharose 4B-PMEinhibitor column. A single protein and PME activity peak was obtained. A biochemical characterization in terms of molecular mass, pi, and kinetic parameters of strawberry PME was performed. In a second step, the thermal and high-pressure stability of the enzyme was studied. Isothermal and combined isothermal—isobaric inactivation of purified strawberry PME could be described by a fractional-conversion model. Purified strawberry PME is much more stable toward high-pressure treatments in comparison to those from oranges and bananas.