Immobilized buckwheat α-glucosidase was prepared in bead shape by radiopolymerization of synthetic monomers. The most suitable ratio of the mixture of acrylamide containing methylenebisacrylamide, potassium acrylate, magnesium acrylate and enzyme solution was found to be 1:1:2:1. The highest activity of the immobilized enzyme was about 50% of that of the native enzyme. Optimum pH was shifted to acidic values by about 0.5 unit by the immobilization. The immobilization increased the stability of the enzyme against heat. Soluble starch was not so good substrate as maltose for the immobilized enzyme, though both substrates were hydrolyzed well by the native enzyme. Nigerose, kojibiose and so on were also produced from maltose or starch sugar by the transglucosylating activity of the immobilized α-glucosidase, as in the case of the native enzyme. A column system of the immobilized enzyme was useful to the enzymatic synthesis of various oligosaccharides.

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The change of volatile components at various ripening stages of field grown tomato fruits and also those of artificially ripened tomato fruits from various ripening stages at 20°C under dark or natural light, were investigated. Volatile components were collected by steam-distillation and headspace trapping method using Porapak Q and cellulose powder, and analysed by GC and GC-MS.
1) From the steam-distillation were identified 79 components, and 68 components by headspace trapping, which were aldehydes, alcohols, phenols, ketones, esters, aromatic hydrocarbons, terpenes and others.
2) Green tomato-like odor of artificially ripened tomato fruits to the stage more than “red” from stage “mature-green” was stronger than that of field-ripened tomato fruits at stage “red” and further, tomato juice-like odor of artificially ripened tomato fruits at 20°C in the dark was stronger than that of field-ripened tomato fruits at stage “red”.
3) Volatile components in the steam-distillate of field-grown tomato fruits generally increased with ripening, particularly middle and high boiling components. On the other hand, volatile components in the headspace showed complicated changes in the course of ripening, especially in the case of artificially ripened tomato fruits.

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Emulsions of lecithin-oil-water were prepared at various pH by adding HCl and NaOH. The concentrations of lecithin in oil-phase (kerosin) were 0.2, 2.0 and 20.0% wt/wt.
It was found that the emulsions at large ionic strength in water-phase are unstable. On the other hand, in the range of the low ionic strength value, the emulsions are comparatively stable. The emulsion stability is higher in basic pH range than in acidic pH range. As the concentration of lecithin in oil-phase increases, this tendency becomes more remarkable. At the pH around 11 to 12, soap in water-phase, resulted from saponification of lecithin, is assumed to affect on stability of emulsion, but the stability becomes lower at higher pH emulsion. In conclusion, emulsifying action of lecithin is affected more strongly by ionic strength in water-phase than pH of water-phase.

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The effect of the nature of oils on the type and stability of emulsions was studied, when lecithin was used as the emulsifier.
The results obtained were as follows.
1) The O/W type emulsions are usually formed, in spite of the oil soluble properties of lecithin.
2) When nonpolar oils are used as the oil-phase, stable O/W type emulsions are formed.
3) In the case where the polar oils are used as the oil-phase, the stability of the emulsions depends on the nature of the hydrophobic group of the oil such as chain length, number of the double bond in the chain, and so on, rather than the nature of the polar groups.
4) The type of the emulsions formed by using vegetable oil as oil-phase is determined by the characteristics of the fatty acid of oil. When the oil of low saponification value and the oil of low iodine value are used as the oil-phase, W/O type emulsions were produced.

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The transition heat (ΔH) of various concentration of sucrose, sodium chloride, lysozyme and bovine serum albumin (BSA) solutions were measured with a Differential Scanning Calorimeter during freezing and thawing.
In sucrose, lysozyme and BSA solutions, and relationship between ΔH (cal/g sample) and water content (x) per g of sample was expressed by ΔH=Ax-B (A, B>0), so the unfreezable water a (g/g solid) was calculated by the equation a=B/(A-B). The values of unfreezable water (g/g solid) in sucrose, lysozyme and BSA solutions were estimated as 0.38±0.04, 0.41±0.06, 0.36±0.04, respectively. In the case of sodium chloride solutions, two transition peaks were found in thermograms. It was considered that the exothermic peak found in lower temperature (peak II) was caused by formation of eutectic mixture of ice and NaCl. The relationship between the second exothermic heat and water content was expressed by ΔH=-Ax+B(A, B>0). The ice content in eutectic mixture was estimated as 2.5_??_2.7g/g NaCl by dividing the A by the latent heat of pure ice.

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Specificity of glycosidase of red clover toward flavonol 3-O-glycoside was investigated. In addition, effects of glycosidase on the browning of isoquercitrin and on the interaction between isoquercitrin and casein were studied by model systems.
A crude enzyme extract from acetone powder showed glycosidase activity for isoquercitrin, hyperin, quercitrin and astragalin. However, the activity for hyperin, quercitrin and astragalin was very weak compared to that for isoquercitrin. A mixture of isoquercitrin and the crude enzyme extract kept in pH 6.0 browned intensely when exposed to sunlight. The degree of browning of the crude enzyme extract or a solution of isoquercitrin was weak. Quercetin was oxidized by the action of both the crude enzyme extract and the sunlight.
After a mixture of crude enzyme extract, isoquercitrin and casein was exposed to sunlight for 3 days, casein isolated from the mixture contained protocatechuic acid as phenolics. The amount of protocatechuic acid contained in the reacted casein was larger than that of the other reacted casein prepared by reaction with only crude enzyme extract omitted.
These results suggested that the interaction between isoquercitrin and casein might be initiated by the liberation of quercetin from isoquercitrin with glycosidase and proceeded by both enzymic and nonenzymic reaction of quercetin, its oxidation products or brown pigment produced from these compounds to casein.

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