Effects of Semi-Rigid Plastic Trays Geometry on Heat Penetration in a Retort Process as Demonstrated via Heat Mapping

Abstract

The present study aims to examine how different geometrically shaped trays of similar volume and construction heat when a food model system is packaged inside them. Triangular, rectangular, oval, and round-shaped trays were filled with a food simulant and processed in a water spray retort system at a rotational speed of 6 rpm. Each retortable tray was fitted with wired thermocouples to monitor temperature variation within the trays. After filling the simulant, the trays were hermetically sealed. Trays were processed in the center of a retort rack in the vessel to prevent any movement during retort processing. Heat penetration data were collected using a total of seven thermocouples placed in each tray. A thermocouple was positioned at the geometric center of the trays, while the remaining six were placed around the tray. All thermocouple ends were located along the same center plane of each tray. Data was collected via data collection software to evaluate the heating profile of each tray. The oval-shaped (OS) tray reached internal equilibrium the fastest (p < 0.05) in 26 min. into processing, with the round-shaped (RS) tray following 28 min. into processing. Modeling software was then used to illustrate heat penetration data. Heat maps for the central plane of each shaped tray were generated at 2, 6, 10, 14, 18, 22, 26, and 28 min. based on physical measurements obtained from thermocouples. These maps were created to assist in understanding the heating effects influenced by tray geometry.