This article reviews the characterization of food ingredients in wheat flour and an agricultural product locally harvested in Wakayama Prefecture, and analysis of the physicochemical phenomena that occur during their processing and storage, in order to achieve improved quality of the food products and enhanced efficiency of the processing. For wheat, as the first step, the expression of genes encoding gluten proteins during kernel ripening was evaluated. In the next step, the effects of non-starch polysaccharides and endogenous enzymes on rheological properties of the dough and batter were studied. Finally, the time-dependent changes in rheological properties of somen noodles, a Japanese traditional wheat product, were analyzed. The effect of preheating at constant temperature on the mechanical properties of Japanese apricot (Prunus mume) jam, a typical agricultural product in Wakayama Prefecture, was also investigated.

High-frequency pulse continuous heating (HFP) is a newly developed electric heating technique that can increase the temperature of slurry foods to over 100 °C in less than 1 s. In this study, we investigated the effect of heating soybean slurry by HFP on lipoxygenase (LOX) activity, the extraction ratio of soy protein, and aroma components of soymilk. Despite the short heating time, HFP inactivated 99 % and 100 % of LOX at 80 °C and 90 °C, respectively. However, conventional heating at 80 °C took 5 min to inactivate LOX. Furthermore, HFP increased the extraction ratio of protein, and decreased the unpleasant beany flavor. These results show that HFP can significantly reduce heating time, thereby enhancing the quality of soymilk.

“Godo” is a Japanese fermented soybean food. This study evaluated the effect of temperature on the quality of godo during storage using microbiological methods. The sample stored at 25°C exhibited a thinner odor and white film on its surface. Bacillus subtilis and Wickerhamomyces anomalus were isolated from the sample. When a godo sample containing the isolated strain of W. anomalus was stored at 25°C, it reproduced the thinner odor and white film. The growth of the strain was inhibited at low temperatures, but not by NaCl. These results suggest that W. anomalus is the cause of godo spoilage, and that godo should be stored at low temperatures.