RESUMO
The objectives of this work were to determine the effect of 3 levels of residual air and 2 different retort motions on the value of the average heating slope of the rate of heat penetration of 3 different viscosities of a food simulant in flexible retort pouches. Pouches were thermally processed in a water spray automated batch retort system using 2 different methods of motion: static and oscillating continuously at a speed of 10.5 rotations per min (RPM) with an angle of 15°. Nine residual air and viscosity combinations were processed during each experimental run: low viscosity with no residual air (LV-NRA), medium viscosity with no residual air (MV-NRA), high viscosity with no residual air (HV-NRA), low viscosity with medium residual air (LV-MRA), medium viscosity with medium residual air (MV-MRA), high viscosity with medium residual air (HV-MRA), low viscosity with high residual air (LV-HRA), medium viscosity with high residual air (MV-HRA), and high viscosity with high residual air (HV-HRA). As the amount of residual air in the pouches increased, the average heating slope value decreased in both static and oscillating motions. As the viscosity of the product increased the amount of residual air affected the average heating slope less in static and oscillating motions. Overall, the oscillating motion resulted in faster rates of heat penetration in all viscosities compared to static mode. The oscillating motion reduced processing times up to 27% compared to static mode. PRACTICAL APPLICATION: This research can be applied to food manufacturers that are retorting foods in pouches. Residual air in pouches has been studied previously; however, with the development of new retort motions, more research needs to be conducted about the effect of residual air in a pouch using the different motions. Food manufacturers can use this information to optimize their amount of residual air based on their product viscosity and retort motion. This could dramatically lower processing time which would save money and increase output as well as potentially increases product quality. This research is aimed at influencing food manufacturers, process authorities, and product developers.