The antioxidant effects of phytic acid (inositol hexaphosphate: IP6) were compared with its hydrolysis products (inositol diphosphate: IP2-inositol pentaphosphate: IP5). The antioxidant activity and chelating activity of metal ion of IP6 and IP2-IP5 (IPns) were examined by using the evaluation of ferric thiocyanate (FTC), β-carotene bleaching, 2, 2-diphenyl-l-picrylhydrazyl (DPPH) radical scavenging, and tetramethylmurexide inhibiting methods. (1) Result of the FTC and β-carotene bleaching methods indicated that the most effective antioxidant was the IP6 and its antioxidant activity was similar to the activity of α-tocopherol. (2) Chelating activities of IPns for Fe²⁺and Cu²⁺ were showed that IP6 has the most strong chelating activity. In proportionately, as the number of phosphate group increases in IPns, the chelating activities are strong. (3) IPns inhibited the marine oil oxidation with Fe²⁺ and that has the strong synergistic effects with α-tocopherol. The inhibition of marine lipid oxidation and the synergistic effects with α-tocopherol followed the order: IP6>IP5>IP4>IP3>IP2.

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Tofu is produced by heating soy milk containing a coagulating agent. In this heating process, soy milk gradually coagulates during heating, and loses the fluidity. In order to examine a relationship between this coagulation and heat transfer mechanism, following experiments were carried out. A tofu container was filled with soy milk and MgCl₂, and then heated in a 90°C constant temperature bath. Using the thermocouples installed in the container, the temperature change during heating was measured. Perfectly solidified tofu was cooled, and the heating experiment was carried out again. The temperature change of solidified tofu was equal to that in the coagulation process. By cutting off the container under heating, the coagulation process of tofu was observed. The observation result showed that the solidification occurred in the initial stage. From the above results, it was deduced that conductive heat transfer was more dominant than the natural convection. A heat conduction equation was solved using the finite element method, and temperature distribution and temperature change of the container inside were estimated. It was proven that internal temperature change in the tofu coagulation process was predictable by solving the heat conduction equation, because numerically calculated temperature agreed with the measured value well. In addition, it was shown that the two-dimensional analytic solution agreed with the solution by the finite element method and that temperature prediction is possible using the analytic solution.

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It is well known that various kinds of essential oils, including Allyl isothiocyanate (AIT), suppress the growth of microorganism. AIT, the main flavoring component of wasabi and mustard, is reported to have strong antimicrobial activity with wide spectrum. However, the strong pungent smell of AIT limits applicable areas for food protection. To reduce the dose of AIT, we tested its activity against fungi under different humidity, RH 100% and RH 34%. We used membrane filters inoculated with Cladosporium cladosporioides, Aspergillus niger and Penicillium citrinum and bean sprout seed inoculated with Penicillium citrinum. We also tested bean sprout seed naturally contaminated with fungi. They were exposed to AIT under RH 100% and RH 34% for 6-72 hours, and then incubated on potato dextrose agar at 25°C. AIT showed stronger antimicrobial activity under high humidity both on membrane filters and bean sprout. This implies moisture plays an important role in AIT activity, suggesting that AIT gas is initially absorbed into water and then contacts fungi. The result showed that the effective concentration of AIT can be reduced under high humidity.

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Changes in the contents of chlorophyll pigments and the chlorophyllase activity during the manufacturing process of Tencha were investigated to clarify following; (1) Total contents of the chlorophyll pigments decreased during the drying process of Tencha due to the decomposition of individual pigment by treatment Tencha at high temperature (80-200°C). (2) Chlorophyll (Chl) a'/Chl a and Chl b'/Chl b (Chl a' and Chl b' were the C-13² epimers of Chl a and Chl b) ratios in Tencha were about 30 and 48%, respectively. These ratios were higher than those (24-25%) in equilibrium state attained in vitro, being assumed that the epimers are more stable during the drying process. (3) Chlorophyllase activity in Tencha decreased to about 1/18 of that in fresh tea leaf in spite of the shorter steaming time (18sec). This result means that the decrease in chlorophyllase activity during the drying process is relatively significant. (4) Pheophorbide a was not contained at all in Tencha, suggesting that the high temperature conditions of drying process were too severe for the chlorophyllase reaction.

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Effects of 0-0.5% calcium carbonate and 0-0.5% calcium hydroxide on gelatinization and retrogradation of 10% corn starch were investigated by measuring the DSC curves, X ray diffraction and mechanical properties. A peak in a higher temperature region on the heating DSC curve of corn starch was shifted to a lower side by the addition of calcium carbonate. A single peak was observed on the heating DSC curve of corn starch with calcium hydroxide. The peak on the heating DSC curve of corn starch being left at 5°C for 24h was shifted to lower temperature side by the addition of calcium carbonate and calcium hydroxide. The peak of X ray diffraction of heated corn starch became gentle by the addition of calcium carbonate and calcium hydroxide. Storage modulus increased by the addition of calcium carbonate and decreased by the addition of calcium hydroxide. Storage modulus of reheated corn starch alone was larger than that of reheated corn starch with calcium carbonate and calcium hydroxide. It was assumed that the addition of calcium carbonate or calcium hydroxide promoted the gelatinization of corn starch and inhibited the retrogradation. Calcium hydroxide showed stronger effects to gelatinization and retrogradation of corn starch than calcium carbonate.

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The effects of calcium carbonate and calcium hydroxide on physical properties of tortilla made from corn fiour were investigated.
The apparent rupture strain of masa (unheated dough) increased by adding 1.0% or 1.5% calcium carbonate, but the apparent rupture stress decreased. The apparent rupture properties of tortilla did not change by the addition of calcium carbonate. But the apparent rupture properties of tortilla soaked in deionized water decreased with increasing concentration of calcium carbonate. The apparent rupture properties of masa, tortilla and tortilla soaked in deionized water increased with increasing concentration of calcium hydroxide.
Starch in masa and tortilla with calcium hydroxide was promoted to smell and hydrate as compared with that with calcium carbonate based on the observation by SEM. Many cavities were observed in the structure of tortilla with calcium carbonate. The water adsorption of tortilla increased by adding 1.0% calcium carbonate. Masa was tinged with red by the addition of calcium hydroxide.
From above results, the effects of calcium carbonate and calcium hydroxide on tortilla were different each other. Tortilla became easy to absorb the liquid by adding calcium carbonate and became difficult to break by the addition of calcium hydroxide.

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Antibacterial action of heat treatment on Escherichia coli IFO3301 (E. coli) in the presence of sodium chloride was investigated. Sodium chloride (0.39M) more inhibited the growth of E. coli than any other reagents under heating at 55°C. The combined effect of sodium chloride and heating was facilitated by an addition of organic acid with longer chain of carbon atoms. The cell-surface hydrophobicity of E. coli increased with sodium chloride under heating. Release of lipopolysaccharide from the cell membrane was enhanced by heating and was promoted with the addition of sodium chloride. Heat treatment increased leakage of UV-absorbing substances from E. coli, while sodium chloride did not enhance leakage of UV-absorbing substances from the cell under heating.

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The effect of freezing and storage conditions on several characteristics of cooked rice balls thawed with microwave-heating were investigated in order to improve the quality of them. Freezing temperature of-13.0--3l-0°C, storage temperature of-31.0°Cand storage period within 7days prevented increasing in white cloudiness and yellowness, and maintained the breaking characteristics of the rice balls compared with the values of control samples. In the thawing process with microwave-thawing, no certain tendency was observed between the heating time and the arrival time to the final temperature among the samples. This might be attributed that the rice ball consisted of three-dimensional assembly of rice grain with not same particle shape. The moisture contents in the central part of rice ball was lower than that in the surface part of it after microwave-thawing. As for this, the moisture in the surface part of the rice ball was maintained by wrapping while molecules inside the rice balls were diffused toward surface part by the higher vapour pressure at the center part of the rice balls rising a rapid temperature increase. It was suggested that starch retrogradation not be a predominant role of deterioration of frozen rice, because the degree of gelatinization of starch for rice ball thawed spontaneously showed no certain tendency to the freezing temperature, the storage temperature, and the storage period.

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Antitumor activity of extracts from vegetables harvested in Tohoku region of Japan was examined using murine P388 myeloma cells. Extracts from edible chresanthemum flower, fuki-no-toh (bud of Petasites japnicus Maxim.), urui (young leaves of Hosta montana F. Maekawa), hops (Humulus Lupulus L.), tarmerick (Curcuma domestica Valeton), and lavender (Lavendula Spica L.) showed strong antitumor activity.

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