High Pressure Inactivation Kinetics of <i>Saccharomyces cerevisiae</i> Ascospores in Orange and Apple Juices

Abstract

ABSTRACT High pressure inactivation kinetics (D and z values) of Saccharomyces cerevisiae ascospores were determined in fruit juices and a model juice buffer at pH 3.5 to 5.0. Approximately 0.5 to 1.0 × 10 6 ascospores/mL were pressurized at 300 to 500 MPa in juice or buffer. D‐values ranged from 8 sec to 10.8 min at 500 and 300 MPa, respectively. The range for z‐values was 115 to 121 MPa. No differences (P≥0.05) in D (at constant pressure) or z‐values among buffers or juices at any pH were determined, indicating little influence of pH in this range and absence of protective or detrimental effects of juice constituents.