Dried bonito (Katsuobushi) is widely used in Japanese cuisine as a traditional Japanese seasoning. The aroma plays an important role in the flavor of the cuisine. The role of dried bonito aroma was demonstrated in experiments with mice : the aroma of a supercritical carbon dioxide extract of dried bonito stimulated the reward system, consistent with the presentation of highly palatable food. The current research revealed the potent odor-active volatiles of supercritical carbon dioxide dried bonito extract (Bonito CO₂ Ex). Aroma extract dilution analysis (AEDA) of Bonito CO₂ Ex identified ten odorants as potent odor-active volatiles with the highest flavor dilution (FD) factor of 15 625 and 3 125 : 2-methoxyphenol showed a FD factor of 15 625 , followed by 2-methoxy-5-methylphenol, 2,6-dimethoxyphenol, 4-ethyl-2,6-dimethoxyphenol, 2,6-dimethylphenol, 2-methoxy-4-propylphenol, 4-hydroxy-3-methoxybenzaldehyde, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (2E,7Z)-trans-4,5-epoxydeca-2,7-dienal and (4Z,7Z)-trideca-4,7-dienal (TDD) with a FD factor of 3 125 . This was the first time TDD was identified in a food. Sensory evaluation of the aroma reconstitutions of Bonito CO₂ Ex revealed that TDD contributed significantly to the Bonito CO₂ Ex aroma. Furthermore, the efficacy of additional TDD to enhance the pleasant flavor of dried bonito broth was confirmed by sensory evaluation conducted by an experienced chef of traditional Japanese cuisine.

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We measured the concentration of antioxidant phenolic compounds and the hydrophilic oxygen radical absorbance capacity (H-ORAC) of extracts from the grains of colored rice varieties grown in two areas of Japan (Rikuzentakada and Daisen) with distinctly different climatic conditions in summer. The accumulated temperature from eleven days to twenty days after heading of rice grown in the Rikuzentakada area was lower than that experienced by the same varieties grown in the Daisen area. The differences in the accumulated temperature ranged from 14.5°C (variety Oumurasakimochi 422) to 27.9°C (variety Okunomurasaki ). The concentration of anthocyanin and cyanidin 3-glucoside in two varieties of waxy black rice grown in Rikuzentakada were higher than that of the same varieties grown in Daisen. The concentration of proanthocyanidin in all varieties of brown rice was also higher when grown in Rikuzentakada than in Daisen. The H-ORAC values of these colored rice varieties grown in Rikuzentakada were higher than those grown in Daisen. The content of protocatechuic acid, which has high radical-scavenging activity, in the total phenolic acid extracts of colored rice was higher in the grains grown in Rikuzentakada than in Daisen. These results demonstrate that low temperatures due to different growth climatic conditions stimulate the production of antioxidant compounds such as anthocyanin and proanthocyanidin, leading to an increase in antioxidant activity in the grains of colored rice varieties.

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Encapsulation of retinyl palmitate (RETP) was investigated in various syrups containing cyclodextrin (CD) and/or maltodextrin (MD) as wall materials by the kneading method. The stability of RETP in various powders was investigated at 40, 50, and 60°C. Encapsulation content and stability of RETP in the powder were improved with the addition of MD and γ-CD to the CD syrup. RETP could not be encapsulated in a mixture of MD and γ-CD. Oil droplet size in the kneaded syrup may affect the RETP encapsulation content of the powders. Degradation of RETP in the powders was well described by the Avrami equation. Further, oxygen diffusion in the wall materials might have affected the RETP degradation rate of the powders. A chemical compensation effect was observed in the degradation of RETP in the powders obtained by the kneading method.

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The tannin-rich fiber from young persimmon (Diospyros kaki) fruits has bile acid-binding properties. We investigated the effect of heat treatment on bile acid binding by this fiber. Furthermore, bread containing persimmon tannin-rich fiber was baked and its bile acid-binding ability was examined in vivo. Although the bile acid-binding ability of the fiber decreased by 20% after heating at 180°C for 20 min, mice fed bread containing persimmon tannin-rich fiber (10% w/w) excreted double the amount of fecal bile acid compared to mice fed the control bread. These results indicate that persimmon tannin-rich fiber can be a useful functional food material when incorporated into breads.

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We analyzed data from microbiology proficiency tests obtained from research laboratories participating in a research project administered by the Ministry of Agriculture, Forestry and Fisheries of Japan. The data obtained from most of the participating laboratories was satisfactory. However, the results from some laboratories did not meet the minimum requirements, even laboratories that had reported satisfactory scores in previous years. The results also showed that, although the standard deviation calculated based on normalized inter-quartile ranges of coliform counts was close to 0.25, the standard deviation obtained for aerobic bacterial counts differed significantly from 0.25, which is the empirical σ_p used by the FEPAS proficiency testing scheme.

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In this study, changes in glutamate decarboxylase (GAD) activity and distribution during storage of rice were examined. GAD activity of brown rice was gradually decreased to 30% during 12 months of storage at 15°C. It was suggested that moisture content and storage temperature influenced the changes in GAD activity. The GAD activity of rice germ was the highest, and the powdered outer layer of brown rice (100-94%) showed 77% of the GAD activity of rice germ. The GAD activity was low in the endosperm, with the largest portion of GAD activity observed in the rice bran.

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Several approaches for controlling the thermal behavior of starch were discussed from the viewpoint of the structural stability and hydration of starch chains, which are closely related to the quality degradation of starchy foods due to the collapse of swollen starch granules. The approaches discussed included the development of an enzymatically cross-linked collagen peptides-starch compound, an amino acid-compounded starch by autoclaving, a fatty acylated saccharide-lysine-starch conjugate by autoclaving, an oleyl starch by lipase-catalyzed synthesis, as well as a technique controlling the thermal stability of starch by adding charged amino acids and charged amino acid-rich peptides. These approaches should be valuable for improving the multiple functional properties of starch in terms of increased structural thermal stability, reduced swelling and viscosity, enhanced thermal resistance, easy vaporization of water from fried coatings, and endowed surface active property.

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