Journal of food science vol:64 issue:5 pages:823-827
Pressure inactivation at room temperature (25 degrees C) of avocado polyphenoloxidase (pH 5.0) in absence or presence of 10 mM ethylene diaminetetraacetic acid (EDTA), NaCl, or benzoic acid or 0.05 mM 4-hexylresorcinol or glutathione could be described by a fractional conversion model. There appeared to be a resistant enzyme fraction (similar to 10% to 20%), necessitating about 825 MPa for inactivation in absence of antibrowning agents. EDTA addition resulted in sensitization of the pressure-sensitive enzyme fraction, which was attributed to the acid effect. Benzoic acid or NaCl addition resulted in a marked stabilization, whereas addition of glutathione resulted only in a minor stabilization of the pressure-sensitive enzyme fraction. 4-Hexylresorcinol displayed a sensitizing effect below and a stabilizing effect above 700 MPa, The pressure dependency of the inactivation rate constant was altered (p < 0.05) by addition of 4-hexylresorcinol or benzoic acid.