Optimal Steam Temperature for Aseptic Processing of Apple Slices

Abstract

Apples are a high-acid food, so less rigorous thermal processing is required to produce a shelf-stable product than is required for low-acid foods. Achievement of a center temperature of 82.2°C is considered satisfactory to make apple slices shelf-stable, whereas a 12D lethality is typically required for low-acid products. When 12D or other lethality is the thermal processing goal, high-temperature processing generally produces higher-quality product than does low-temperature processing with the same lethality endpoint. In this study, experiments showed that for apple slices aseptically processed in a steam environment to a center temperature of 82.2°C, low-temperature processing achieved higher quality than did high-temperature processing. A finite difference theoretical analysis confirmed that low-temperature processing should be expected to give higher quality for this or similar processes when the particle center temperature is the goal of the process.