Microwave heating is characterized by rapid heating, the selective heating of water and energy savings. The author has investigated the development of new processes for the drying of fruits and vegetables using microwave technology. In a series of studies, it was found that pre-freezing, which converts sample moisture to ice crystals and damages the tissue structure, further improves the drying efficiency of microwave-vacuum drying, suppresses sample shrinkage during drying and produces porous dried materials similar to freeze-dried products. This porous structure is effective in improving the texture, the water absorption rate of dried products and the efficiency of the milling process in powder production. Furthermore, the author confirmed the conditions under which the sample temperature can be maintained at a constant level throughout drying by controlling the microwave power output, and the relationship between temperature and the quality characteristics of the dried product. Drying technologies that exploit microwave properties show potential for future development and will lead to the effective and energy-saving use of untapped food resources in agricultural production.

Aiming to produce a reduced-salt miso with the same taste and aroma as Sendai miso, the production process including preparation conditions and fermentation was optimized. Preparation tests were carried out on the medium and manufacturing scale for a process in which the salt concentration was 9 %, the moisture content at preparation was 46 %, and fermentation was carried out under the same conditions as in the production of Sendai miso. Instrumental analysis (gas chromatography and taste sensors) and sensory evaluation showed that the reduced-salt miso was of the same quality as Sendai miso. In addition, a storage test was carried out to examine quality changes over time, such as taste and aroma, assuming sales. After a four-month storage period, fermentation progressed and the brightness (Y%) decreased at a storage temperature of 20 °C, but no significant changes were observed at 15 °C, indicating that the quality was maintained. These results led to the establishment of a manufacturing process for reduced-salt miso with the same quality as Sendai miso.

Although several methods are effective in assessing aroma components exhaled during meals, they do not possess the capability to monitor real-time changes in aroma components within the nasal cavity. Systems for the orthonasal and retronasal aromas of beer were established using a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF/MS) system. The PTR-TOF/MS combined with a dynamic and reactive flavor release monitoring system (headspace-PTR-TOF/MS) or the PTR-TOF/MS was used for the measurement of orothonasal or retoronasal aroma, respectively. The constituents of the orthonasal aroma were stable and maintained a constant concentration for some time after the start of the measurement. However, the retronasal aroma gradually decreased with respiration after swallowing the beer. Some of the constituents decreased rapidly and disappeared after swallowing, some decreased gradually, and some maintained a constant concentration with almost no decrease, indicating a change in composition ratio of aroma components in exhaled breath after swallowing changes with respiration. The aroma components immediately after drinking beer are qualitatively different from those when enjoying the lingering aroma after swallowing. Moreover, the composition ratios of the retronasal aroma components differ from those of the orthonasal aroma components. These findings clarify that beer aroma qualitatively differs before consumption, immediately after swallowing, and at some time after swallowing.

When foods and seasoning solutions are vacuum packaged together using a chamber-type machine, the resulting pressure gradient causes the solution to enter the pores of the foods, enabling the seasoning of raw vegetables. In this study, we investigated the seasoning characteristics and properties of vegetables after vacuum packaging. A 3 % NaCl solution was used for the vacuum packaging of Japanese radishes, which imparted a moderate level of saltiness in a shorter amount of time than without vacuum packaging. Additionally, mass loss and shape shrinkage resulting from leakage due to dehydration, typically caused by hypertonic solutions, were minimized, resulting in novel textures, such as easily chewable pickles. This suggests that vacuum packaging enables the production of foods with a salty taste and a crisp, juicy texture.

Many existing food manufacturing processes rely on empirical knowledge and are not often designed or performed with a thorough understanding of the underlying phenomena. Drying and rehydration processes are one example of this. The water transfer behavior within foods during these processes varies depending on the manufacturing and cooking conditions, significantly influencing food quality. Based on the observation that the brightness of food changes in response to its moisture content, a novel method for measuring water transfer within foods was developed. Using this approach, new mechanisms of water transfer in pasta were proposed. In addition, a new framework for understanding these complex phenomena, referred to as the artificial intelligence comprehensive and reverse analysis method, was suggested. The effectiveness of this method was demonstrated by elucidating the complex mechanisms by which the gluten structure in noodles affects food texture. This review provides an overview of our findings.