A Theoretical Study for Determination of Quality Equivalent Points for Volume Average Quality Evaluation in Conduction Heating Canned Foods

In the present study, a set of quality equivalent points, that is, points where the retention of a particular quality attribute at the end of a thermal process is equal to the volume average quality retention, was determined for conduction heating products in cylindrical containers. For this, initially, the temperature distribution inside the product during the thermal process was numerically calculated, assuming uniform initial product temperature, constant heating and cooling medium temperatures, and infinite heat transfer coefficient between the cylinder walls and the heating or cooling medium. Next, remaining concentration data at the end of the process were obtained at various points within the container for a heat labile quality factor following 1st-order degradation kinetics. Thereafter, the volume average remaining concentration for the quality parameter under consideration was calculated and the quality equivalent points were identified. The influence of product, quality factor, and process characteristics on the location of the quality equivalent points, was examined. For every case investigated, the entirety of quality equivalent points was modeled by the use of a single parameter, the empirical J value. For most cases of common practice, a J value between 0.34 and 0.40 was found appropriate for volume average quality retention calculations. Thus, by collecting temperature data during processing at a quality equivalent point, product quality at the end of the process can be assessed.