Experimental validation of models for predicting optimal surface quality sterilization temperatures

Abstract

An experimental procedure was developed to validate experimentally the theoretical optimal process temperatures giving the maximum quality at the surface of conduction heating products for specified levels of sterility. The method involved filling a can with a 10% bentonite solution, placing glass capillaries containing a food quality indicator at the surface, and processing it at different temperatures for the necessary time in order to attain a specified sterility value at the least-lethality point. The acid catalysed sucrose hydrolysis reaction was used as a chemical time-temperatureintegrator for a quality index of heat sterilized products. At a pH of 3.8, the kinetic parameters D121.150C and z values of this reaction, were 214min and 31"C, respectively.Final surface retentions of sucrose compared well with theoretically predicted values from simulation modelling. Optimal temperatures calculated using either numerical computer optimization or generalized regression equations were in the range of experimentally determined optimal conditions.