The rapid hardening of bread heated with microwave has well been known. This considerable hardening was never found on bread heated by ordinary thermal treatment. Therefore, it might be caused by changes of physico-chemical properties of bread's constituents. In order to probe the relationship between the process of bread hardening and bread staling, and to discuss the hardening process, the behavior of bound water and the retrogradation of gelatinized starch in these bread were investigated. (1) Microwave heating increased the bound water of bread in accordance with the rapid hardening. (2) Microwave heating increased the starch-gel in bread, but the gel seemed to be unstable because of the remarkable decrease in the extractability during storage. (3) The digestibility and X-ray diffraction showed that the process of hardening was different from that of bread staling.

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In order to study the food preservative effect of ozone, microbicidal effect of ozone was investigated employing cereal grains, cereal grain powders, peas, beans and whole spices. The conditions empoloyed to evaluate the microbicidal effect were: ozone gas concentration 0.5-50ppm, temperature 5-50°C, time 1-6 hour and flow rate 100L/min. Results were as follows: (1) The microbicidal effect of ozone was affected by contact concentration. Higher contact concentration resulted in greater microbicidal effect on various cereal grain powders. When buckwheat whole grain with hull (Japan), black matpe and black pepper (seed) were treated with 5.0ppm ozone, microbicidal effect of ozone was maximum. (2) Whole, halves and ground samples of buckwheat were treated with 50ppm ozone continuously for 1 hour at 10°C. Microbicidel effect of ozone was maximum in whole and minimum in ground. (3) Lower temperature resulted in greater microbicidal effect on cereal grains, cereal grain powders, peas, beans and whole spices except black pepper. (4) Longer contact time resulted in greater microbicidal effect on cereal grains, cereal grain powders, peas, beans and whole spices except buckwheat whole grain with hull and black matpe.

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Ozone treatment on cereal grains, cereal grain powders, peas, beans and whole spices was carried out with 0.5-50ppm ozone concentration at 10°C for 1 hour, and changes in thiamin and riboflavin contents were investigated. Results obtained were as follows: (1) 0.5-50ppm ozone treatment of above food ingredients was found to induce a little thiamin decomposition. Especially, thiamin decomposition were detected in samples of buckwheat flour, well-milled glutinous rice flour and white pepper (seed) treated with 50ppm ozone. When the ozone concentration was increased from 0.5 to 50ppm, thiamin retention decreased from 80-100% to 60-97%. On the other hand, decomposition of thiamin was affected by distribution of thiamin and cell wall in cereal grains, beans and whole spices. (2) Decomposition of thiamin in water solution by ozone treatment was lowered by the addition of 1-5% saccharide, but was enhanced by the addition of 1-5% halogen compound. (3) There were no significant differences in the content of riboflavin by the ozone treatment on cereal grains, beans and whole spices.

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Three kinds of phosphatases, one main component (phosphatase A) and two secondary components (phosphatase B₁ and B₂), were separated and partially purified from Shii-take, fruit body of Lentinus edodes, by ammonium sulfate fractionation, two steps of ion-exchange chromatography and gel filtration. Phosphatase A was homogeneous on disc polyacrylamide gel electrophoresis. The appearent molecular weight was estimated to be 21×10⁴ by gel filtration and 7×10⁴ by SDS-polyacrylamide gel electrophoresis. Phosphatase A was identified as an acid phosphatase (EC 3. 1. 3. 2), since it effectively hydrolyzed various phosphomonoesters but not phosphodiesters, and the optimum pH for some phosphomonoesters was 4.0. It was markedly inhibited by NaF, K₂Cr₂O₇, Na₂MoO₄, Na₂WO₄. It was stable at pH 4.0 below 60°C, but relatively unstable at pH range above 7.0 on heating. Phosphatase B₁ and B₂ resembled to phosphatase A in substrate specificity, pH-activity curve, thermostability, but were distinguishable by elution pattern on ion-exchange chromatography and molecular weight.

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In order to evaluate the effect of seeding time and cultivar on seed weight, protein, oil, carbohydrate, and ash contents, and fatty acid composition of soybean seeds, 8 cultivars were grown at intervals of 20 days on seeding time from 1st: May 9 to 5th: July 28 in 1975. As the seeding time was late, light seed weight, low protein, oil, oleic acid, and linoleic acid contens and high carbohydrate, ash, palmitic acid, stearic acid, and linolenic acid contents were observed. Compared with 3rd and 5th cultures, however, 4th culture showed high oil and oleic acid contents. Further, 5th culture was high protein, linoleic acid, and linolenic acid contents and low oil, palmitic acid, stearic acid, and oleic acid contents in comparison with 4th culture. As to the variation of oil content and fatty acid composition, it was presumed that oil and oleic acid in 4th culture were affected by large difference between high and low temperature during ripening and oil, oleic acid, linoleic acid, and linolenic acid in 5th culture by low temperature during ripening. Significant differences were observed in seed weight and all chemical components except oleic acid and linolenic acid among the seeding time and in seed weight and all chemical components among the cultivars. From the contribution ratio of the seeding time and cultivar, seed weight and chemical components except oil were high in cultivar.

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By using the alcoholic fermented juice of the de-astringent Japanese persimmon cv. 'Sanja' (Alcoholic persimmon juice) as the raw material, a series of persimmon vineger fermentation tests was carried out with 2 strains of Acetobacter sp. isolated from persimmon and selected as well as a control strain of the type culture (Acetobacter aceti IFO-3281), to analyse the changes in the contents of organic acids, acetoinic compounds and free amino acids, in the course of fermentation. (1) When the 3 types of Acetobacter sp. were inoculated to the alcoholic persimmon juice containing 5% ethanol, and fermented at 28°C for 18 to 24 days, a persimmon vinegar with an acid concentration of 4.7% or higher was obtained. (2) The mash inoculated with the A-33 strain and the control showed a high degree of turbidity, whereas that inoculated with the A-114 strain was virtually clear. (3) Contents of lactic acid, succinic acid and malic acid in the mash decreased after assimilation by Acetobacter, in particular at the early stage of fermentation. (4) Every mash showed a decrease in the content of 2, 3-butanediol during the fermentation, whereas the content of acetoin and diacetyl increased markedly to over 10-fold and 2-fold, respectively 24 days after the fermentation. The marked increase in the content of acetoin was considered to be caused mainly by the degradation of organic acids or condensation of acetaldehyde and not by the oxidation of 2, 3-butanediol contained in the persimmon juice alcohol. (5) The content of the free amino acids in the mash decreased during the fermentation. The rate of reduction was higher when the isolated bacteria were used compared with the control strain, and a larger number of amino acids was recorded. (6) Every mash fluid 24 days after fermentation lost the smell of sun-drying, and gave an aroma of ripening less pronounced than that of rice vinegar and a mellow taste. (7) The content of water-soluble tannin, reducing sugar and total nitrogen decreasd throughout the fermentation period.

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A curd coagulated by means of lactic fermentation from heated soymilk was ripened for 3 weeks with inoculation of a white mold starter, Penicillium caseicolum. Changes of proteins during the ripening were investigated by gel filtration and electrophoresis. Activities of proteases (endopeptidase, aminopeptidases and acid carboxypeptidase) in cur were also measured through the ripening. The ratio of water soluble nitrogen to total nitrogen (ripening ratio) reached to approximate 60% at 2 week's ripening and the finished product showed a good flavor and texture. Of water soluble nitrogen, lower molecular weight components such as free amino acids and comparatively higher molecular weight components consisting of partially hydrolyzed soy protein occupied about 30% and 70%, respectively. Electrophoretic analysis of curd proteins showed that subunits of 7S globulin and acidic subunits of 11S globulin decomposed in accordance with progress of ripening and bands of these subunits completely disappeared after 3 week's ripening. Activities of neutral endopeptidase, aminopeptidases (I and II) and acid carboxypeptidase in curd appeared at 1 week's ripening with growth of mold and rapidly increased with the ripening. These activities penetrated into center of portion of curd from surface. Proteases in curd and extracellular proteases of P. caseicolum which extracted from wheat bran medium were identical.

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The effect of modified atmosphere (MA) packaging storage on preservation of Shiitake Mushroom (Lentinus edodes (Bark) Sing.) was evaluated from the aspect of some chemical characteristics. Shii-take were packed hermetically in a polyethylene film pouches in 100μm thickness and were stored at 1°C for 3 weeks. Thereafter, the shii-take were exposured to air in the nonhermetical polyethylene film pouches to keep at 10°C for 1 week. On the other hand, for control, some shii-take samples were stored at 10°C in polyetylene film pouches nonhermetically without pre-storage of MA. (1) The concentration of O₂ and CO₂ during the MA were 1-2% and 10-14%, respectively. The accumulation of 1.2ppm of ethanol was observed after 3 weeks of MA storage. (2) The decrease of arabitol was well prevented by MA packaging. However, arabitol markedly decreased when shii-take was exposured to air after MA storage. (3) The amount of total free amino acids increased in the control sample, while that in the MA sample was relatively constant.Among thefree amino acids, glutamine was remarkably produced as the deterioration of shiitake progressed in the non-hermetical storage. While no significant changes were observed in glutamine content during the MA storage. The rate of glutamine production in the MA sample which was transfered to non-hermetical storage was as rapid as that of control sample. (4) The changes in malic acid content were rather similar to those of glutamine. (5) As the conclusion, MA packaging storage effectively keeps freshness of shii-take during the hermetical storage. And on exposure to air, the quality of shii-take changes like as non-treated one except arabitol content.

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