Bread was made by a straight dough baking process from wheat flour partially substituted with rice paste. The rice paste was prepared by grinding down rice grain that had been soaked in water with a mortar and pestle. This grinding method markedly reduced the bread quality with respect to loaf volume, as large granules of more than 100μm in length remained in the rice paste. On the other hand, rice paste ground in a pulverizing mill comprised uniform particle size distribution with an average particle size of 6μm. Using this paste comprised of minute particle starches improved loaf volume, crumbing properties such as hardness and homogeneity, and sensory evaluation score of the bread. The minute starch particles reduced water absorption in the rice paste, allowing for water absorption in the wheat. Dough made with this rice paste was tender and leavened well, suggesting that these improved qualities of rice paste resulted in better bread quality.

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We investigated whether consumption of cocoa raises human body surface temperature. Healthy female student volunteers (age 18-24) were enrolled in this study. We measured their body surface temperature and peripheral blood flow in a stringently air-controlled room (temperature, 22±0.5°C ; humidity, 50±5%). First, the effect of pure cocoa consumption at 60°C and 37°C was compared with that of soup consisting of the same nutritional composition and water. At 60°C, pure cocoa tended to increase the peripheral body temperature at the wrist, ankle and tip of the foot, while at 37°C it tended to maintain the peripheral body temperature at the wrist. Next, defatted cocoa at 60°C was compared with control drink consisting of the same nutritional composition. Defatted cocoa increased the temperature at the forehead (p<0.05) and maintained the temperature at the finger tips (p<0.05) ; this same tendency was also observed at the abdomen and waist. Using the same defatted cocoa and control drink samples, we examined the situation immediately before sleeping. Defatted cocoa increased the temperature at the wrist, ankle and tip of the foot (p<0.05). Thus, cocoa consumption results in increasing or maintaining the human body surface temperature, while defatted cocoa consumption effects are especially remarkable.

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In this study, we examined the effects of lyophilized powder of foam components (foam powder) obtained from the bulb of jumbo leek on liver disorders. Using a rat model, acute liver disorders were produced by D-galactosamine hydrochloride (GalN) administration to induce fulminant hepatitis and chronic liver disorders were induced by ethanol administration. These effects were then compared with those of freeze-dried powder of the whole bulb and curcumin. We also attempted to isolate and identify the saponin, the estimated active component in the leek. Both foam powder and freeze-dried powder decreased the induction of hepatocyte necrosis in GalN-induced acute liver disorders and prevented the occurrence of ethanol-induced chronic liver disorders in rats by inhibiting the absorption of alcohol from the stomach. From the freeze-dried whole-bulb powder, we isolated the known steroid saponin, karatavioside A (C₅₀H₈₀O₂₃, MW : 1048).

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The third crop of green tea leaves contains a relatively large amount of catechins, giving its hot-water extract a bitter taste. The loquat leaves have strong enzymatic activity of catechin oxidization and contain chlorogenic acid which accelerates this oxidation. We investigated the production method of fermented tea by mixed kneading of the third crop of green tea leaves and loquat leaves and examined the most appropriate time to harvest green tea leaves. Fresh green tea leaves (27kg) were withered by blowing air over them (70°C) for 20min in a primary tea-rolling dryer. The tea leaves were then mixed with fresh loquat leaves (3kg) and kneaded with a tea roller at room temperature for 20min. The amount of catechins in the green tea leaves was decreased by this process, resulting in hot-water extract of mixed tea leaves that was bright red and had improved taste and aroma. The best quality fermented tea was produced from the third crop of green tea leaves harvested 35 days after the second crop harvest. We established a new production method to manufacture fermented tea by mixed kneading of the third crop of green tea leaves and loquat leaves using a primary tea-rolling dryer and tea roller. Using this method, good quality fermented tea was manufactured.

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1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging capacity and oxygen radical absorbance capacity (ORAC) of ten sweet potato cultivars with various flesh colors were measured. The DPPH radical-scavenging activity (DPPH-RSA) was almost the same among the sweet potato cultivars with white, yellow, and orange flesh ; however, purple-fleshed sweet potato cultivars showed about 10 times higher activity than those with other flesh colors. A similar tendency was observed for ORAC. Therefore, electron and hydrogen atom transfer reaction-based assays could both detect the high antioxidant activity of purple-fleshed sweet potatoes. Moreover, a high correlation between the DPPH-RSA and ORAC values was found for three cultivars and seventeen breeding lines of purple-fleshed sweet potato (R=0.894). Based on these results, our DPPH radical assay appears effective as an alternative method for estimating ORAC values of purple-fleshed sweet potatoes.

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Application of green tea extract (GTE) to food preservation was investigated. Viable counts of cucumber pickled overnight at 10°C with seasoning solution containing acetic acid, NaCl, and/or GTE were determined during cold storage at 10°C. Viable counts did not increase above the initial values for 7 days of treatment with seasoning solution containing 0.1% acetic acid, 2% NaCl, and 0.05% GTE. Use of these seasoning components alone or in combination showed no bacteriostatic effects on the pickled cucumber. Viable counts of Escherichia coli O157 : H7 did not increase when the cucumber was artificially contaminated with this bacterium and then pickled overnight with the seasoning solution containing 0.1% acetic acid. These results indicated that the addition of GTE to seasoning solution containing both acetic acid and NaCl prolongs the shelf life of overnight pickled cucumber.

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[in Japanese]

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