Microengineering-based structuring and valorization of lipid foods were investigated. First, to control the fatty acid composition of triglycerides, modified lipases were prepared using emulsifiers and fatty acids, and applied to interesterification of fats and oils. Stearic acid was suitable for lipase activation, showing high interesterification activity. The structure of stearic acid-modified lipase was first analyzed by small-angle X-ray scattering. Next, the membrane separation performance for crude oil was investigated using hydrophobic non-porous membranes. Degumming and decolorization tests for crude soybean oil were conducted, revealing that the rejection of phospholipids and the decolorization ratio were more than 95%, representing higher quality compared to conventional methods. Membrane application to used edible oil also showed better performance than the conventional adsorption method. For practical use, improvement of the permeate flux is needed. Finally, a technology was developed for preparing monodisperse emulsions using fabricated microchannels (MCs). Efficient emulsification was achieved using asymmetrically structured MCs. The slit structure caused large distortion of the oil-water interface, and the interfacial tension induced spontaneous droplet formation. Laboratory-scale MC emulsification equipment was industrialized and used for various applications.

The purpose of this study was to clarify the rice endosperm glycolytic enzyme activity and the viscoelasticity affect the taste evaluation of polished rice of different varieties, production areas, and production years, as an applied study that reflects the actual conditions of rice in circulation. That is, the level of each enzyme activity of various polished rice was quantified, and the differences were examined. In addition, viscoelasticity measurements of cooked rice and a taste evaluation test were carried out. We investigated the relationship between enzyme activity and viscoelasticity with taste, and obtained the following findings. 1. The level of enzyme activity had a high correlation with the hardness of cooked rice and the freshness of polished rice. 2. Among the enzymes, the level of β-galactosidase activity had the highest correlation with taste. 3. The viscoelasticity affected the taste of cooked rice and was particularly highly correlated with the hardness and stickiness of cooked rice. 4. The higher the activity levels of the starch-degrading and cell wall polysaccharide-degrading enzymes, the softer the cooked rice. 5. The results of the taste sensory evaluation test and the index of the “Shokumi Kanteidan” obtained from the appearance, hardness, stickiness, and freshness of cooked rice showed a correlation with the level of enzyme activity and the viscoelasticity.

To expand rice consumption, there has been an increase in the utilization of rice flour in various food fields. Rice flour attributes are determined mainly by the properties of the raw material and the processing conditions, and have an influence on the manufactured products. For the application of rice flour as a wheat flour substitute, a small particle size and low damaged starch content are desirable; however, high starch damage can result from the milling of polished rice. Thus, in the production of fine rice flour, it is important to pulverize the grains to a particle size where the polished rice exhibits appropriate water absorption.In assessing various rice types for flour milling, detailed pulverization and processing tests are required. The production of fine rice flour is costly because optimal water absorption and drying are required. Therefore, in order to establish an efficient production method for fine rice flour, we examined the relationship between grain hardness and milling properties of rice and water absorption by modifying the structure of the raw material. The relationship between SKCS (single-kernel characterization system) hardness and the polishing property of 98 brown rice samples was determined; floury rice lines with a low polishing rate were characterized by a hardness of 40 or less. Brown rice samples with a hardness of greater than 55 were appropriate for polishing, and when milled (screen-less type of pin-mill) by limiting water absorption, exhibited a superior milling property of small particle size as the hardness value decreased. In such a case, the lower the hardness, the less the degree of starch damage of the rice flour. When the rice was completely absorbed with water or pulverized using a pin-mill that structurally passed through a mesh, the rice flour produced showed a specific range of median diameter and starch damage regardless of the hardness of the brown rice sample. In the case where the raw rice was crushed in advance and absorbed water, improved efficiency was observed; however, by limiting water absorption to about 25 %, it was possible to produce the target fine rice flour (starch damage degree 6 % or less, median diameter 75 µm or less). These results indicate that fine rice flour can be efficiently produced using a combination of rice varieties with excellent milling properties, crushing the rice grains prior to soaking and limiting the water absorption.

After culturing 75 strains of 19 yeast species from food on potato dextrose agar medium at 25 °C for 5 days, mass spectra were acquired using VITEK MS^TM plus to prepare SuperSpectra (SSp). Verification of the prepared SSp showed that the reliability of identification was more than 80 % except for Schizosaccharomyces spp., Sterigmatomyces elviae, Starmerella apicola, S. etchellsii, Wickerhamomyces subpelliculosus, Zygosaccharomyces rouxii, and Z. bisporus. It was difficult to distinguish Z. bailii, Z. parabailii, Z. pseudobailii, Z. mellis, and Z. siamensis, by using their SSp, but they can be identified as Z. bailii complex for Z. bailii, Z. parabailii and Z. pseudobailii, and Z. mellis-siamensis complex for Z. mellis and Z. siamensis. The identification reliability level was affected by the medium used for cultivation of yeast. For the Brettanomyces (Dekkera) spp., there were cases where they were difficult to identify when a mass spectrum with peaks that had a sufficient number and intensity was not obtained, or when the major peaks were similar. Improvement of the methods for sample treatment and SSp creation were required.

Alkaline-treated rice flour, which was prepared by washing rice flour with dilute alkaline solution, was added to wheat flour to make bread, and the bread-making quality was evaluated. The bread with alkaline-treated rice flour (Y+RA) showed increased gas retention of the dough and specific loaf volume compared to the bread containing untreated rice flour (Y+R). The alkaline treatment broke down the compound starch granules of the rice flour, which inhibit gluten network formation, into small starch granules and smoothed the surface of the granules. It also reduced the amount of damaged starch in the rice flour. Texture analysis showed that the crumb hardness of Y+RA tended to be softer than that of Y+R, and was comparable to that of bread made with commercial strong flour (C). In sensory evaluation, the score of Y+RA was significantly higher than that of Y+R, and was equivalent to that of C. These results suggest that alkaline-treated rice flour has higher bread-making quality than untreated rice flour, and that incorporation of alkali-treated rice flour can produce rice flour-added bread with good bread-making quality.