The effects of trehalose and glycerin on the rheological properties of 1.0% agar gels treated with freezing-thawing were studied by measurement of breaking properties, storage modulus and cooling curves, and observation of syneresis. Although the values of rupture properties of thawing gels with 30-40% trehalose were larger than those of thawing agar gel alone (p<0.05), those of the thawing gels with 40% glycerin were larger than those of pre-freezing agar gel alone (p<0.05). The storage modulus of thawing agar gel alone decreased remarkably with an increase in temperature. By addition of trehalose and glycerin, the decrease rate of storage modulus of thawing gels along with a decline in temperature became slowly. Addition of glycerol inhibited the syneresis of the thawing gels. The freezing temperature lowered with increasing concentration of glycerin.
From the above results, it is suggested that damage to the agar gel associated with freezing-thawing could be reduced by hydration properties of trehalose and glycerin, and by antifreeze activity of glycerin.

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As to the evaluation of the texture of deep-fried foods, the biting sound is considered to be one of the important factors. In this study we tried to establish an objective method for the evaluation of the texture of foods, and thus examined applicability of sound analysis. To simulate human mastication sounds, a mechanical device was developed. In addition, a sound recording system and a sound analysis system were also constructed. The results of two subjective evaluation tests showed a high correspondence between the sensory evaluation by mastication and the acoustic evaluation of sounds produced by the mastication simulator, suggesting that an acoustical parameter can become an objective index of texture. A study of the correlation between acoustical indices, i. e. sound pressure level, sharpness and roughness, and the subjective evaluation of the texture, showed that these acoustical indices were useful to objectively evaluate the texture of foods. Furthermore, the usefulness of the acoustical analysis of bone conduction of sound and of mastication pressure was demonstrated.

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The method of soaking plant materials in an enzyme solution after freezing, and infusing pectin lyase into the plant tissue quickly under reduced pressure was devised. By infusing the enzyme, the plant material was softened and disintegrated into single cells in a short time. The residual ratios of β-carotene and anthocyanin in single cells of carrot and purple-fleshed sweet potato obtained by this method were higher compared with the conventional method employing stirring, and the stability of volatile compounds in single cells was also high. Moreover, this enzyme infusion method under reduced pressure after freezing is extremely useful as an advanced technology of producing food materials holding arbitrary hardness.

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The effective manufacturing process of persimmon leaf tea was investigated for maintenance of high level of the functionality. By steaming treatment for 10 minutes following the drying process, total ascorbic acid and radical scavenging activities were increased in comparison with the short time steaming. The level of total ascorbic acid and radical scavenging activities of the machine drying method was higher than that of the shade drying method. A high level of anti-allergy activities was observed in all processes, and no difference was observed in anti-allergy activities resulted from the steaming time and drying method. These results show that the steaming treatment for 10 minutes following the machine-drying method was suitable for the production of persimmon leaf tea.

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Disulfides bonds in soybean proteins were estimated by labeling with a fluorescent reagent, monobromobimane (mBBr) and subsequent electrophoresis. Prior to the labeling by mBBr, disulfide bonds in the proteins were chemically reduced by 0.5mM dithiothreitol (DTT) at room temperature. Acidic and basic subunits of glycinin, and Bowman-Birk protease inhibitors were detected as major bands in the soybean proteins. It is found that fluorescence intensity of basic subunit of glycinin correlated significantly to the rupture stress of Tofu using 33 varieties of domestic soybean.

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To identify the effect of variety, stage of maturity and hereditary factors of maternal and paternal lines on free type of total sugar, free sugars i. e. sucrose, raffinose and stachyose, protein and oil contents and 100 seed weight in Japanese soybeans, 104 samples of 95 varieties and lines cultivated in 6 Agricultural Experiment Stations from the North to the South in 1992 were analyzed. The values of range, average, and coefficient of variation were as similar as those of our previous paper. On the medium and late maturing varieties compared with early varieties, significant high free type of total sugar and sucrose and low oil contents were observed. Free type of total sugar and sucrose contents were negatively correlated with oil content. The group of late maturing variety in the Hokkaido (northern area) and Nagano (central area) Stations was high in free type of total sugar content and low in oil content. The high free type of total sugar and sucrose and low oil contents were characteristic of medium and late maturing varieties in the Hokkaido Station. In regard to influence of maternal and paternal lines on hybrid variety, no correlation was observed in free sugars except raffinose content, whereas, positive correlation in protein and oil contents and 100 seed weight. Sucrose content was influenced by maturity on variety, but not by maternal and paternal lines. As for genetic interaction on sucrose content, hybrid varieties were not influenced by maternal and paternal plants.

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We measured of contents 6 minerals in 8 cultivars of pigmented brown rice harvested in 2002, compared with mineral contents of Koshihikari cultivated under the same field. In the results, it was shown that Ca content of pigmented brown rice was higher than that of Koshihikari cultivar. Mineral contents in rice were highly influenced not only by difference among cultivar, but also difference in cultivating area. The relative mineral contents to those in Koshihikari cultivated in same field might be useful to clarify the cultivar difference.

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The effects of structural properties and moisture content on the thermal conductivity of fruits and vegetables were investigated. The transient heat probe method using twin probe was used for the determination of thermal conductivity. Thermal conductivity at initial moisture content of eight kinds of fruits and vegetables was measured at 10°C. Especially, thermal conductivity of radish, ranging in moisture content from 0.0 to 94.6% (w. b.), was measured at 10 to 40°C. Structural properties of radish, such as apparent density, true density and internal porosity, were investigated at several moisture content. The apparent density and the dried solid density were measured by liquid displacement method, therefore, true density and internal porosity were calculated, respectively. Assuming three-phase system consisting of air, water, and solid, each volume fraction was calculated. Measured results of thermal conductivity were compared with the heat conduction model proposed by Rahman, which involve temperature, moisture content, volume fraction, and thermal conductivity of each component. Measured results were agreed well with the predicted results by Rahman's model.

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The manufacturing method for low caffeine green tea remaining the contents of epigallocatechin-3-O-(3-O-mehtyl) gallate (EGCG3"Me) and strictinin, that have been observed anti-allergic actions, were investigated using ‘Benifuki’ tea leaves in the first crop and ‘Benihomare’ tea leaves in the second crop season. Under the condition of steeping picked tea leaves in water over 85°C for 90, 90°C for 60 or 95°C for 60, caffeine content was reduced by half, while the contents of EGCG3"Me, strictinin, catechins and amino acids were maintained in the processed tea leaves. From quality of appearance, it was supposed that the manufacturing green tea was good after soaking in water at 90°C for 60 and spin-drying, to reduce caffeine content.

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