In order to improve the utility of cooking ovens, we conducted heat transfer mechanism analyses of a convection/steam combined oven by focusing on steam condensation. Spherical wet gauzes were used as the sample material. The heat transfer mechanisms were analyzed by considering the heat balance on the surface of the spherical gauze using the measured mass change of the sample, the temperature change of the sample surface and gas flow. In this manner, we could estimate the heat flux in terms of heat transfer and heat flux changes with time. The estimated data were used to generate diagrams that visually depicted the heat transfer mechanisms in terms of heat flux changes with time. The diagrams provided to visually understand and compare each heat transfer quantity, incremental moisture content and heat quantity generated because of steam condensation on the sample material, as well as drying rates under different heating conditions. In addition, the heat transfer mechanism of a steam convection oven was analyzed using this method. We analyzed the effects of each setting condition (e.g., temperature, humidity, and velocity) on the heat flux, moisture content, and temperature of the sample material during heating. From the analysis results, it was possible to understand and compare the heating characteristics between oven types, and to set the proper conditions for achieving optimal oven heating.

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The effect of amylose content of rice on the physical properties of rice porridge bread was investigated. Four kinds of rice porridge bread were prepared by substituting waxy or low amylose, medium amylose and high amylose rice for 15 % or 30 % of the total amount of wheat flour in wheat flour bread. In the 15 % rice porridge bread samples, the specific loaf volumes (SLVs) remained almost unchanged from wheat flour bread, although that of high amylose rice porridge bread was slightly smaller. The SLVs of 30 % rice porridge bread tended to be smaller than that of wheat flour bread. In addition, values for the viscoelastic properties of crumb specimens of the rice porridge bread samples were shown to be smaller than that of wheat flour bread, except for that of 30 % high amylose rice porridge bread. These results indicate that SLV and viscoelastic properties of rice porridge bread are affected by net amylose content, that is the combination of amylose content of rice used in the rice porridge and the ratio of rice substituted for wheat flour.

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A randomized controlled open-label crossover trial was conducted to evaluate the effect of ingesting a drink containing Peucedanum japonicum Thunb. (PJT), a member of the Umbelliferae family, on leg swelling in 10 healthy Japanese women. On the test day, subjects ingested the test drink or water as a control, followed by loading with water. Calf circumference was measured at its maximum, and at 3cm above and 5cm below the maximum with a tape measure at 0, 2, 4 and 6h and with a 3D digitizer at 0 and 6h. In addition, calf volume was measured with the 3D digitizer and self-reported symptom score of leg swelling was evaluated using a visual analog scale (VAS) at 0 and 6h. The incremental calf circumference at 5cm below the maximum circumference, the incremental calf volume and the symptom score were lower at 6h after ingestion of the test drink compared to the control. Therefore, PJT may have an anti-edema effect in healthy women. Hesperidin and diosmin, which were identified as components of PJT powder, may partly contribute to this activity.

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Here we report our development of a novel freeze concentration apparatus for suspension crystallization. The apparatus was evaluated after freeze concentration of Pomelo (Citrus grandis Osbeck) juice produced in Kochi prefecture. The stock juice before the concentration process was 11.0 °Brix. The consistency of the resulting juice concentrate ranged from 13.2 to 38.7 °Brix. Levels of fructose, glucose, sucrose, citric acid, malic acid, ascorbic acid, limonin, naringin, hesperidin and amino acids were higher in the juice concentrate than in the stock juice, when analyzed by the HPLC method. Brix degree was linearly correlated with the levels of each component. After freeze concentration processes (n=7) ranging from 29.7∼42.0 °Brix, the average recovery rate was 87.9%. These results suggest that our apparatus is effective for stable concentration of Pomelo juice and has the capability to recover over 90% of juice concentrate.

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Apricot seeds are removed during food processing and discarded as waste. The apricot kernel within an apricot seed contains the cyanogenic glycoside, amygdalin. Since amygdalin generates harmful hydrogen cyanide upon hydrolysis by emulsin, an enzyme found in apricot kernels or β -glucosidase in the human body, it is necessary to remove amygdalin in order to make apricot kernels edible. Thus, we immersed the apricot kernel in ethanol solutions of various concentrations, and examined which concentration reduced amygdalin the most efficiently. As a result, amygdalin was most efficiently reduced in ethanol solution concentrations ranging from 10% to 30%. Moreover, in order to clarify the reduction mechanism of amygdalin in apricot kernels by ethanol solution immersion treatment, we assessed the rate of elution from apricot kernels and the rate of amygdalin hydrolysis in ethanol solutions. As a result, the maximum rates of hydrolysis and elution were observed in the 20% and 50% solutions, respectively. From these results, enzyme degradation and elution of amygdalin from apricot kernels were considered to be important factors in the reduction of amygdalin. Moreover, we established a method for reducing the hydrogen cyanide generated by hydrolysis of amygdalin.

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Soy foods are known to be effective for the amelioration of lipid metabolism. We investigated the effect of fermented soymilk on lipid metabolism in rats fed a high fat diet. Male Sprague-Dawley rats aged 7 weeks were fed either a control diet (AIN-93G), high fat diet including 28.5% powdered beef tallow (60% fat energy), or test diet where 24.1 % of the high fat diet was replaced with fermented soymilk (10% soy protein in diet) for 5 weeks. Although it was previously reported that the plasma triglyceride level in rats fed a normal diet (AIN-93G) was not decreased by the ingestion of fermented soymilk, it was found in the present study that the level of rats fed a high fat diet containing fermented soymilk was significantly suppressed compared with those of rats fed a high fat diet. Although the hepatic cholesterol level in rats fed a high fat diet was reduced by the ingestion of fermented soymilk, a significant decrease in plasma total cholesterol level, to the level in rats fed a normal diet, was not observed. These lipid metabolism-modulation effects in rats fed a high fat diet seem to depend on the physiological action of fermented soymilk supplemented to the diet.

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This study focused on the high radical-scavenging activity of onion extract (onion-flavor seasoning made from onion) and aimed to clarify its changing profile. Radical-scavenging activity, amount of major flavonoids, and browning degree during onion extract processing were measured. In heat processing of concentrated onion juice, radical-scavenging activity and browning degree significantly increased, and most flavonoids disappeared. The principal component of the radical-scavenging activity of onion extract was found to be melanoidin. The fractionation of onion extract using solid-phase extraction based on hydrophobic interaction showed that the fraction exhibiting higher hydrophobicity had higher radical-scavenging activity and browning degree.

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In the present study, we report on the nutrient composition, amylase titer and superoxide anion-scavenging activity (SOSA) of Chinese yam (Dioscorea opposita Thunb., nagaimo) tubers harvested in Hokkaido, in comparison with those, previously published, of potato (May queen variety), a major crop, from the same district. Nagaimo had high contents of water and calcium compared to potato, and was expected to be a good supplier of some vitamins, such as α -tocopherol, vitamins B₁ and B₆, and ascorbic acid. The total dietary fiber content was lower in nagaimo, but it had a high proportion of water-soluble dietary fiber, compared to potato. Moreover, nagaimo possessed a lower starch content compared to potato, with 25% amylose and a high proportion of resistant starch. As for free sugars, nagaimo had higher contents of glucose and fructose, its sucrose level being almost the same as in potato. It was confirmed that the major amino acids in nagaimo were glutamic acid and arginine, dissimilar to those in potato. Determination of the amylase titer in tubers showed that nagaimo had almost the same activity compared to potato, leading to the presumption that eating raw tubers of nagaimo causes no intestinal problems directly related to its amylase activity. A notable SOSA was also found in nagaimo, but the antioxidant activity was slightly weaker compared to potato.

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