Heating of food products based on convective heat transfer from hot air to the food products is common in food processing operations, such as oven and drying process. Food is typically heated in humid air that contains a small amount of steam/water vapor. If the air contains a large amount of steam, steam could condense on the surface of the food, the dew point being higher than the temperature of the food. Moreover, when the temperature in the heating chamber is higher than the boiling point of water (100°C) at atmospheric pressure, the chamber space could become filled with pure steam with a temperature above the boiling point of water; this steam is called superheated steam. In this report, superheated steam and its utilization are described from the interdisciplinary perspectives encompassing thermodynamics, mechanical engineering, and food engineering. A heat transfer model is proposed to investigate the steam condensation followed by condensate evaporation occurring in the initial stage of food heating. The effects of humidity on food drying using superheated steam and high-temperature air are investigated experimentally.

In order to acquire frost resistance, various organisms produce various ice crystal-controlling materials. Ice crystal-controlling materials include the supercooling-facilitating materials that inhibit heterogeneous nucleation caused by foreign materials, and ice recrystallization suppressing materials that suppress the growth of minute ice crystals in water. We have successfully produced multiple extracts with supercooling-facilitating activity from unused resources produced during food processing production. Among these extracts, the extract with the highest activity was coffee refuse extract. Furthermore, they also discovered the same activity derived from melanoidin, which is produced during food processing and cooking. As part of the implementation of extracts, we attempted to establish an unfrozen preservation technology for fruits and vegetables. Through field spraying of figs, harvested figs become unfrozen after being stored at -2°C for 15 days, extending the retail restrictions from 5 days to 15 days. Furthermore, by absorbing a mixture of coffee refuse extract and miso extract during hydroponic lettuce cultivation, the harvested lettuce could be stored unfrozen at temperatures below 0°C for about two weeks.

A method for determining the optimum temperature for the separation of two polyphenols by polystyrene divinylbenzene resin reversed phase liquid chromatography with the ethanol-water mixture mobile phase was proposed based on the iso-resolution curve concept. The distribution coefficient and the stationary phase diffusion coefficient were formulated as a function of temperature T and ethanol concentration I. From the iso-resolution curve, the productivity P* was calculated as a function of T. It was found that there is an optimum T, where the highest P* can be obtained.