Two isoforms of polygalacturonase (PG, E. C. 3. 2. 1.15), namely, PG-1 and PG-2, were purified from the endosperm of polished rice, (Oryza sativa cv. Koshihikari, the most extensively producted rice variety in Japan). PBE 94 chromatforcusing indicated pIs of 5.6 and 5.1 for PG-1 and PG-2, respectively. These enzymes had same molecular weights approx. 67 kDa and consisted of a monomer. PG-1 and PG-2 exhibited optimum activities at pHs 5.0 and 4.5, respectively, and optimum temperatures of 60°C. Furthermore, these were stable at near-neutral pHs and retained 40% of their activities at 70°C. These results suggest that PG-1 and PG-2 are activated when rice is being cooked, and that the amount of pectin that combined with cells decreased by approximately 40%. Moreover, purified polygalacturonases decomposed pectin during rice cooking. It is surmised that the two PGs in the rice endosperms, decompose the pectin during rice cooking, thereby loosening the intercellular cement that gives firmness to plant tissues, and affecting the texture of cooked rice.

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We have developed the first commercial refrigerator with an inverter compressor which saves a significant amount of energy while maintaining the cooling performance. This refrigerator is provided with such functions as control of compressor rotation speed suitable for a commercial refrigerator, reduction of cold heat leak, and operation control of anti-condensation heater. In comparison with the conventional model, the new model achieved about 60% energy saving.

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As a trial to estimate food demand and supply on the basis of various aspects, we calculated the food self-sufficiency ratio based on vitamin C, an essential nutrient. We calculated the amount of vitamin C supplied from each food group according to the calculation method of the Food Balance Sheet developed by the Ministry of Agriculture, Forestry, and Fisheries. The result shows that the major sources of vitamin C are fruits and vegetables, particularly citrus fruits. For each food group, we divided the amounts of vitamin C into the amounts of vitamin C in domestic foods and the amounts of vitamin C in imported foods. The result shows that the total amount of vitamin C obtained from domestic foods has been decreasing over the last 30 years and we were not able to provide the recommended dietary allowance of vitamin C from domestic foods in 2001. The food self-sufficiency ratio based on vitamin C in 2001 was less than 70%. In spite of the decrease in the amount of vitamin C obtained from domestic fruits, the total amount of vitamin C obtained from all fruits has been increasing over the last 30 years because of the increase in the amount of imported fruits. This is also one of the reasons we have increased our dependence on vitamin C obtained from imported foods and the food self-sufficiency ratio based on vitamin C has decreased in Japan. As a result of calculating the food self-sufficiency ratio based on vitamin C as an essential nutrient, for providing the recommended dietary allowance of vitamin C obtained from domestic foods for all Japanese, it is very important to increase both production and consumption of domestic fresh fruits.

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The Ministry of Health, Labour and Welfare revised the detection method for foods containing allergy inducing substances in June of 2006. Since then, the mandatory display of certain allergy inducing substances including egg, milk, wheat, peanut and buckwheat was started. In this revision, the detection kits for allergy inducing substances were not specified, because the detection method was described as a guideline. In this report, the author described the outline of the new revision mentioning detection for the allergy inducing substances and the profiles of their standard materials. Moreover, the other 20 allergy inducing substances including kiwi fruit, crab, prawn (including shrimp), soybean, and walnut were encouraged to display upon label. The detection method for these substances has been under development.

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