O/W emulsion is used for many food materials and its stability is important to improve new food functionality such as tastes, and flavors, or to retain healthy materials. Because surfactants are usually mixed as stabilizers, selection of surfactants is a dominant factor for the stabilization of O/W emulsion. In the present paper, the characterization and stability of O/W emulsion prepared with polyoxyethylene [20] sorbitan monopalmitate (Tween 40) or polyoxyethylene [20] sorbitan trioleate (Tween 85) were evaluated physico-chemically by a dynamic light scattering method, turbidimetry and electrochemical measurements of oil droplet. Moreover, surface tension was measured for the surfactants, oil and their mixtures. It was observed that there were some differences between Tween 40 and Tween 85, in particle size distribution and the aggregation behavior of oil droplets, and adsorption on their surface, on the contrary, ζ-potential of oil droplet and the fraction of surface coverage with the surfactants were identical. It was concluded from the time courses of turbidity changes that Tween 40 was superior to Tween 85 in the stabilization of the oil droplets.

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A method for measuring creep of Konjac sols (Seiko and Arako-sols) was investigated. Each sample for the measurement was 2mm in thickness and 55mm in diameter, which was supported by a non-adhesive tape. The tape was removed from the sample just after the beginning of the creep measurement. The deformation at non-load was measured initially and then was subtracted from the deformation at load. The sample of 3.2% had non- deformation by the body force, but that of 3.0-2.2% had 0.2-0.3% deformation in diameter. The measured values for sols were compared with the apparent viscosity and the viscoelasticity of Konjac gels. For the samples of Seiko and Arako, the viscoelasticity of their gels had a good correlation with the results of the creep measurement of each sol. But for the samples of Arako, the viscoelasticity of the gels had no correlation with the apparent viscosity of the sols.

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Utilization of enzymes for suppression of sweet potato discoloration after cooking was examined. A treatment of steamed sweet potato pasts prepared from cultivars of Beniotome and Benihayato with commercially available chlorogenic acid esterase (CAE) suppressed the discoloration of the past significantly. CAE decomposed all chlorogenic acid isomers of caffeic acid and quinic acid, whereas 4CQA and 5CQA were decomposed faster than 3CQA. Since the intensity of the pigmentation of caffeic acid reacted with ferrous ion was less than that of chlorogenic acids, it was estimated that the suppression of the sweet potato past discoloration by CAE resulted mainly from the decomposition of chlorogenic acids to caffeic acid and quinic acid. Moreover, pectinases slightly contaminated in the CAE preparation were also estimated to suppress the discoloration by acidification of the pasts through the production of uronic acid from sweet potato pectin during the enzyme treatment.

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Crude extract of Mesona procumbens Hemsl. (CEM), dark brown liquid was extracted with a weak alkaline from dried labiate herb grown in Taiwan. When tapioca starch was cooked rapidly with dilute CEM solution, sticky cold paste formed hard gel like agar. The gel is one of the popular desserts in Taiwan. Rheological behaviors of the gel were investigated. The cooking viscosity by Rapid Visco-Analyzer and the dynamic modulus of cold paste body were increased as the concentration of CEM. The optimum concentration of CEM was 2% for tan δ, but of starch was saturated at 5% for G'. The similar behaviors of gel were recognized as for potato and waxy corn starch. However, it was no effect on the crude extract of Japanese perilla. Therefore, the gelling effect to starch paste may be the characteristic of Mesona herb. When the same process was applied to the paste that was completely dispersed in an autoclave, it did not form a gel. It appears that the gelation needs to existence of swollen starch granules, though it was glutinous starch of amylose free. Higher modulus of the gel was obtained at pH 7.0 and by dialysis of CEM.

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We attempted to measure the visual characteristics of cooked rice using image analysis. In this study, measurement parameters were defined by luminance analysis to examine correlations of measurement data with a sensory test. In addition, experimental conditions were determined by estimation of scatter on data. More specific results were described below. To describe the visual characteristics of cooked rice, the characteristics were divided into brightness and the amount of luster. Average luminance was defined as a parameter for brightness of cooked rice. Threshold (= digital number 185) to extract the luster on cooked rice was determined, and the cumulative number of pixels above the threshold was defined as a parameter of the amount of luster. Since measurement data were closely related to sensory test, it was considered that those parameters were valid for estimating the visual characteristics of cooked rice. In the examination of cooking conditions, the amount of added water was required remain constant and that amount was determined to be 1.5 times the rice weight. According to this method, it is able to efficiently measure 100 samples per a day.

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We developed a method to measure the freshness of individual rice grains. Brown and white rice grains were treated with 1% guaiacol, 3% hydroperoxide and 2% p-phenylenediamine in series to stain according to their catalase activities. Color of each grain on a black rubber plate was measured using a tristimulus colorimeter (Minolta CR-300, 8mm of a diameter of measuring area). Differences in L^* value and b^* value between the grain on the plate and the plate only were expressed as ΔL^* and Δb^*, respectively. The colors of stained brown rice grains became thinner as stored at 30°C for longer period. The ΔL^*s and Δb^*s of brown rices stored at 30°C for 10 weeks were very different from those of them at the beginning of storage. The ΔL^*s of white rices changed in a similar way, too. Also in the case of the storage at low temperature (10°C), the colors of stained brown rice grains became the thinner, the longer period they were stored for. The ΔL^*s and Δb^*s of brown rices harvested in 1997 were very different from those of them harvested in 1994, when store at 10°C. This method would be useful to measure the freshness of each rice grain.

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To investigate the effect of varieties of dried Shiitake mushrooms on their tastes, the effect of chemical components on their sensory evaluation, five kinds of common dried Shiitake Mushrooms cultivated on logs in Japan and one kind of an ambiguous variety cultivated on sawdust substrate beds in China were collected in 1994, 1995 and 1997. In our previous papers, we reported chemical composition and the behavior in rehydration of dried Shiitake mushrooms. In this paper, we carried out the sensory evaluation of various cooked dried Shiitake mushrooms. The rehydration of the samples was carried out at 5°C for a time needed to reach to 90% of equilibrium absorption of water. As for the overall of the sensory evaluation, there were not extremely differences among the mushrooms cultivated on logs in Japan but there was a few characteristic in some varieties. In spite of low contents of umami components, high evaluation was given to a variety which had little aroma and taste components. On the contrast, mushrooms cultivated on sawdust beds in China were significantly lower than all varieties of Shiitake mushrooms cultivated on logs in Japan. It was mainly because that the evaluation of texture and aroma was lowest and that bitterness was strongest in all Shiitake mushrooms evaluated. High nitrogen and lentinic acid contents were not always related to high evaluation, but bitterness and texture were strongly related to the overall of the sensory evaluation.

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A sensory evaluation was conducted by an expert panel to examine the effect of pasteurization temperature on the sensory characteristics of UHT processed milk. UHT pasteurization at 120, 130 and 140°C was carried out by an indirect plate heating method. The denaturation rate of whey proteins and rennetability are the most reliable indicators of heating degree of the UHT process affecting the physicochemical properties of milk. At temperatures of 130°C or above, lactulose may also be used as an indicator. Palatability was mainly judged on the preferences of odor and aftertaste, freshness and the intensity of the milk taste. There tended to be a preference for UHT processed milk pasteurized at 130°C for 2 seconds (UHT 130). From the results of the sensory evaluation and the principal component analysis, it was found that the milk body related to the sensory attributes of milk flavor, milk taste, viscosity and fattiness became stronger as the UHT processing temperature increased. The body was particularly strong for milk which was pasteurized at 140°C for 2 seconds (UHT 140), however, there were no particular differences observed in characteristics of the UHT processed milk evaluated by the panel.

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Previously, we have reported that the mixing shirasuboshi (boiled and semi-dried whitebait) with citrus fruit juices was effective to solubilize calcium from it. We determined the optimum amount of citrus fruit juices (sudachi and lemon juice) or vinegar to be added for solubilization of calcium. Solubilization ratio of calcium from shirasuboshi was increased with an increasing amount of citrus fruit juices or vinegar. Citrus fruit juices showed a significantly higher effect in solubilization than that with vinegar. Sensory assessment of shirasuboshi mixed with 5, 10, 20, or 40% of citrus fruit juices or vinegar was performed by fifteen member panels. Addition of 20% of sudachi juice gave the best score in taste, flavor and comprehensive assessments. These results suggest that both solubilization ratio of calcium and sensory factors should be considered for the development of bio-functional food stuffs in shirasuboshi mixed with citrus fruit juices.

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Thermophysical properties of apple juice of concentration ranging 10%∼45% (w/w) were measured at temperatures between 10°C∼50°C. The twin probe method was used to measure the thermal conductivity of sample solution. The specific heat of sample solution was determined using a twin isoperibol calorimeter. Using these measured results and density, the thermal diffusivity of apple juice was estimated. Based on the effects of concentration and temperature on these thermophysical properties, these thermophysical properties of apple juice were written as a function of both concentration and temperature, respectively.

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Eighty strains of lactic acid bacteria were isolated from rice and processed rice products to examine antimutagenic effect. Antimutagenic activity on living and killed cells of lactic acid bacteria and the fermented milk against 4-nitroquinolinel-oxide (4-NQO) were determined according to the Ames test using Escherichia coli WP2uvrA. Ten strains having high activity of antimutagen were selected and were identified as Lactobacillus casei subsp. casei, Lactobacillus plantarum and Lactobacillus fermentum. Living cells of 10 strains selected showed higher antimutagenic activity than killed cells of them. Milk added glucose and rice flour that digested with α-amylase was used to as materials of fermented milk products. The fermented milk products indicated high activity of antimutagen, but the activity was lowered by heating

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A hundred grams a day of fermented milk prepared with Lactobacillus casei subsp. casei 327 which was isolated from rice and Streptococcus thermophilus 510 was administered to four healthy volunteers for two weeks. The number of Lactobacillus strain in feces increased for three volunteers and this strain showed the same characteristics as L. casei subsp. casei 327.
The fermented milk was administered to 27 healthy female volunteers including 14 constipated female and 13 non-constipated female under same conditions.
By the administration, constipated female stool frequency was increased significantly and the shape, color and hardness of their feces were improved, while only the hardness of feces was improved for non-constipated female.

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To obtain fundamental information on the production of fucose-containing xyloglucan oligosaccharides from peanut hulls by hydrolysis with industrial enzyme preparations, we have studied the structure of the oligosaccharide units of xyloglucan in peanut hulls. The oligosaccharide units of xyloglucan in peanut hulls were XXXG, XXLG, XLXG, XXFG, XLLG, and XLFG [where each (4)-β-linked D-glucosyl residue in the backbone is given a one-letter code according to its substituents: G=β-D-Glc; X=α-D-Xyl-(6β)-β-D-Glc; L=β-D-Gal-(2)-α-D-Xyl-(6β)-β-D-Glc; F=α-L-Fuc-(2)-β-D-Gal-(2)-α-D-Xyl-(6β)-β-D-Glc] in an approximate molar ratio of 33:4:5:25:6:27. An industrial hemicellulase preparation, Cellulosin T2, was found to be an appropriate enzyme source for producing xyloglucan oligosaccharides from peanut hull polysaccharides.

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A straining process of potatoes by a professional chef was examined by motion analysis. The force applied by him in the process was expressed as its vertical component, horizontal component and their resultant force. Their maximum forces measured were 11.35kgf, 2.92kgf and 11.83kgf, respectively, indicating that the vertical component was predominant over the horizontal component in the resultant force through the whole process of straining. This experiment showed that the motion analysis was well suited to explain a load on food materials dynamically and that the analysis would be useful for investigation of cooking-processes.

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