Aluminium contents and their ionization rates in 22 different food samples of vegetables, fruits, mushrooms and algae were examined. Higher aluminium contents were found in spinach (687μg/g), "komatsuna" (222μg/g), garland chrysanthemum (117μg/g), "hijiki' (201μg/g) and kiwi fruit (22μg/g). Aluminium contents in the other samples were ranged approximately from 5 to 10μg/g on dry matter basis. The ionization rate of aluminium in "komatsuna", spinach, garland chrysanthemum, kiwi fruit, "shiitake (raw)" and "shimeji" in hydrochloric acid solution (pH 2) were lower than the other samples. The ionization rate of aluminium in 10 food samples (onion, watermelon, pumpkin, cucumber, broccoli, "hijiki", strawberry, indian lotus, cabbage and "aokubi daikon") were ranged from 50 to 100%. These results suggested that the amount of aluminium absorbed by body would not correlate with the aluminium contents of various foods.

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Membrane emulsification is a new technology based on the use of a microporous membrane for preparation of emulsions. A membrane emulsification system allows the preparation of highly monodispersed emulsions, and it is expected that this technology will have many applications in the food industry. In the present study, we used tubular microporous glass membranes to prepare O/W emulsions from food ingredients. We investigated the type of pore size of the membrane and oil phase, the type and concentration of emulsifiers, the circulating velocity of the continuous phase and the permeant pressure of the dispersion phase as factors influencing the dispersed droplet size of emulsions and the monodispersed emulsion. We also studied ways to improve the rate of preparation of monodispersed emulsions in practical applications. A monodispersed emulsion could be prepared by selecting appropriate operating conditions, such as the concentration of emulsifiers, the circulating velocity of the continuous phase, and the permeant pressure of the dispersion phase. With the oil phase and emulsifiers tested, the average dispersed droplet diameter of the emulsions was typically about five-times greater than the average pore diameter of the membrane. Results obtained using sodium caseinate as the emulsifier differed from findings with other emulsifiers. The rate of preparation of the monodispersed emulsion could be increased by selecting the type and concentration of emulsifiers in the water and oil phases.

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The properties of soymilk, which prepared from soybeans of six varieties having different subunit composition, were studied. Soymilk's protein particles were fractionated in size by differential centrifugation. The particles of more than 100nm, 100-40nm, and less than 40nm in diameter were obtained as large protein particles (LP), medium protein particles (MP), and supernatant protein (SP), respectively. The LP content in all raw soymilks decreased and the MP content increased by heating, but the MP content in soymilk prepared from GILM (7S rich) did not increase so much by heating. When calcium chloride was added to the soymilks, the protein solubilities of the soymilk from Karikei 434 (11S rich) decreased sharply between 6 and 8mM calcium chloride, while that from GILM decreased sharply between 10 and 12mM. The concentration of magnesium chloride, which began to decrease the protein solubilities, was similar to that of calcium chloride. But a decreasing slope of the protein solubilities by magnesium chloride was gentler than that by calcium chloride. The precipitation pH of protein by magnesium chloride was 0.1 pH higher than that by calcium chloride. Phytate in the soymilks accelerated a pH-decrease on the addition of calcium chloride. These results suggest that higher calcium and magnesium concentrations are required for the 7S globulin rich-soymilk coagulation than for normal soymilk coagulation, and that the pH decrease by the addition of calcium in phytate rich-soymilk is greater than that in low phytate soymilk.

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The relationship between the constituents of globin hydrolyzates (GH) and GH-gel formation was investigated. When the gel filtration was carried out immediately after globin was hydrolyzed by 0.8M citric acid at 95°C for 15min, each molecular weight (MW) of the components which were contained in the resulting GH was similar to or less than that of globin. However, after the GH-solution was allowed to stand at 30°C for 24hr, the aggregates above MW 700000 were formed. The similar aggregates were also found in a powdered GH preparation (GH-preparation) and in a dissolved GH gel. These aggregates were made up of polypeptides below MW 15000. Hydrophobic ipteraction chromatography revealed that the GH-preparation contained three different components, GHP 1, GHP 2 and GHP 3. The fraction (P 1) corresponding to the aggregates or the fraction (P 2) corresponding to globin obtained by gel filtration was composed of GHP 3, and GHP 1 and GHP 3, respectively.

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Minced fish meat (Alaska Pollack) was used to make “Kamaboko” samples containing additional NaCl (0-1w/w%) and/or starch (0-10w/w%), and treated with alternating current (0-20V) at various frequency (50HZ-10kHz) to heat up to 90°C. The resulting products were examined for their breaking strength, color and fine structure. Heating rate was found to be dependent mainly on the frequency, and increased at 10kHz 7.5 times as fast as that of a boiled sample. The products had similar light values (L, a, b) and always higher breaking strength whose highest value was 1.6 times as large as that of boiled one. The dielectric loss was found to be maximum at around 10kHz, indicating that it would contribute to the quick heating and the better formation of gel. These results suggest that water is individually separated in the matrix of protein gel and that the gel has the maximum dielectric constant at specified frequency according to the gel structure and distribution of components.

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Natto is one of the Japanese traditional fermented foods. Natto bacilli belong to Bacillus subtilis and abundantly grow on boiled soybean, and secrete unique sticky materials and flavor components. The physiological role of foods has recently been paid attention, but natto with special physiological role has rarely been developed. Natto bacterium, the strain KFP 419 with high elastase activity was isolated, and the natto employed KFP 419 was manufactured. It was one of the mutants which were obtained from the parent strain, KFP 355 by ⁶⁰Co irradiation. KFP 419 and the parent strain were identified as Bacillus subtilis Cohn. Natto with KFP 419 showed higher γ-glutamyltranspeptidase (γ-GTP) activity and stronger relative viscosity than natto with the strains of the marketed starters. No significant difference of the constituent contents was shown between the former natto and the latter by general food analysis. According to the organoleptic test, the former natto showed higher values on taste, stickiness and so on, though the former showed stronger flavor than the latter. Elastase activity of the former was twice to 3 times higher than the latter.

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β-Lactoglobulin from cow's milk was hydrolysed in 0.1M buffer solutions by using pepsin, trypsin, chymotrypsin and other 13 kinds of food processing proteolytic enzymes. The hydrolysates were analysed by HPLC chromatography with a GPC column. At pH 3.5, only Oryentase 20A completely digested β-lactoglobulin. At pH 7.0, trypsin, chymotrypsin, Oryentase ONS and Denazyme AP completely hydrolysed β-lactoglobulin. On the Whole, the degradation hydrolysis rate of β-lactoglobulin was different between pH 3.5 and pH 7.0, showing its higher resistance against hydrolysis at pH 3.5 than at pH 7.0. However, S-carboxylated β-lactoglobulin was rapidly hydrolysed to a large extent at pH 3.5. Therefore, it was considered that the resistibility of β-lactoglobulin to the hydrolysis at pH 3.5 depends on the three-dimensional structure of β-lactoglobulin. Then β-lactoglobulin was processed by heating (60°C, 80°C, 100°Cand 120°C for 10 minutes) in the solution of pH 3.5 and pH 7.0. Heat processing over 80°C in pH 7.0 and over 60°C in pH 3.5 caused an increase of β-lactoglobulin hydrolyzability, probably due to its denaturation by heating.

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Quality changes of sous vide processed mitsuba were evaluated in relation to the differences of processing temperatures (100, 90 or 80°C) and degrees of vacuum (30 or 100mmHg) in chamber of packing machine. Surface color of sous vide processed mitsuba at 100 or 90°C was superior than that of other processings. There were no considerable differences among processing temperatures on total chlorophyll content. However, absorption spectrum of acetone extract at the region of 415nm differed due to the formation of pheophytins a and b during processing. Results of sensory evaluation showed that the sous vide processed mitsuba had more inherent aroma and flavor than those of the usual processing. Surface color of processed mitsuba changed to yellow during storage, especially at 20°C. Pheophytins a and b were formed significantly with yellowing of processed mitsuba. L-ascorbic acid content decreased sharply during storage at 20°C, but was slowly at 5°C. Anaerobic bacteria increased after 2 days at 20°C and 6 days at 10°C when the mitsuba were stored, but did not increase even after 8 days at 5°C. These results indicated that processing under reduced pressures at 90°C or higher temperatures provided good quality of mitsuba. And that the storage at 5°C or low temperature gave microbiological safety condition.

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The effects of pressure pretreatment before cooking on the hardness of vegetables were studied.The vegetables used here were Japanese radish, carrot, burdock and potato. The hardness of the samples which had been treated at 50-500MPa for 0-120min at room temperature before cooking at 99.5°C was evaluated. The ratio of hardness of the pretreated vegetables to that of the untreated ones, called "relative hardness", increased substantially with the magnitude and the retention time of applied pressure. The relative hardness of vegetables pretreated at 400MPa for 120min was in the range of 2-3 after 30min cooking. The period of optimum cooking time for the desirable hardness of vegetables was prolonged twice by the pressure pretreatment. This phenomenon, the suppression of softening in the cooking process, depended mainly on the time after reaching the prescribed pressure and little on whether the pressure was retained for a long time or released immediately after the short-time application. The replaceability of the standing time after release of pressure and the retention time during pressurization indicates that the loss of intra- and intercellular water molecules and ions, induced by the membrane collapse due to pressure, proceeds at almost the same rate under atmospheric pressure as at high pressure. This suggests that the loss of water plays an important role in determining the pressureinduced hardening. This work also shows that pressure pretreatment at room temperature can be used to avoid the overcooking of vegetables instead of preheating.

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Some properties of kojic acid glucoside were compared with those of kojic acid. As for antibacterial activity and tyrosinase inhibitory activity, those of kojic acid glucoside were less effective than those of kojic acid. As for chelation with Cu²⁺, Cd²⁺, and Co²⁺, the overall stability constants of kojic acid glucoside and kojic acid were very similar.
Furthermore, the stabilities of kojic acid glucoside and kojic acid against light and heat were investigated. Kojic acid glucoside were more stable than kojic acid against light and heat about 2.5 and 5 times, respectively.

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Yanagimatsutake mushrooms (Agrocybe cylindracea (Fr.) Maire) were divided into three stages, a young fruit body having an unopened hymenium veil (just after formation of the primordia), a matured fruit body having an opened veil (just after opening of the veil), and an over-matured fruit body having a completely opened veil (after releasing of brown spores). We traced the change in constituents during three stage of fruit body formation of Agrocybe cylindracea. The results are as follow: (1) Water contents were almost similar during fruit body formation. (2) Crude protein and ash decreased with growth, but carbohydrates slightly increased. (3) Aspartic acid, threonine, serine, alanine and tyrosine decreased with growth, but lysine and arginine slightly increased. (4) The content of 5'-GMP was larger in matured than young and over-matured fruit bodies. Over-matured fruit body had a significantly low content of 5'-GMP.

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