For more than three decades, membrane technology has drawn keen attention and has been applied to various fields in food industry in Japan. The Research Association of Membrane Technology for Food Industry (MRA), which was established by the Japanese Ministry of Agriculture, Forestry and Fishery in 1982, continued the activity to accelerate the spread of membrane technology for 6 years. In 1989, Membrane Research Circle of Food (MRC) was established by the researchers and technologists in industry-government-academia. Watanabe, one of the present authors, who worked for Ministry of Agriculture, Forestry and Fishery at that time, participated in the activity as an executive committee member of MRA and as a chairperson of MRC, respectively. In 1996, one year after Watanabe moved to Niigata University as a professor of food engineering, Food Engineering Division in Food Research Laboratory in Niigata Prefecture was established. In 1997, when MRC 10th Autumn Workshop was held in Niigata, Membrane Application Research Circle (MARC) for food industry in Niigata was established. The research to apply membrane technology to food industry in Niigata started with collaboration among local companies just after Watanabe's coming to Niigata University. The establishment of MARC accelerated the widespread of knowledge of membrane technology. The research projects in the authors' laboratory and companies were: 1.Establishment of clarification and recycle system for rice washing drainage from packed rice cake manufacturing plant, 2.Establishment of concentration and recycle system for pickles seasoning drainage, 3.Development of squeeze and clarification technology of soy-sauce fermented broth by micro-fiber cloth for direct membrane filtration, 4.Gamma-Amino butyric acid production using clarification with membrane, 5.Sterilized and clarified raw soy-sauce production by ceramic MF membrane Under present circumstances, the research subjects of No.4 and No.5 came successfully into practical use.
The retention behaviors of caffeine and vanillin in columns packed with thermostable octadecyl silica gels and zirconium particles with an extremely stable thin layer of cross-linked polybutadiene were observed using water at various temperatures or methanol mixed with water at 30°C as the eluent. For both columns, the retention times of the solutes at a specific flow rate became shorter at higher temperatures when water was used as the eluent. The effect of the temperature on the retention behaviors of the solutes were examined for the latter column in the temperature range of 70°C to 210°C. It was shown that the retention behaviors could be more effectively controlled by changing the temperature when using water as the eluent than by changing the methanol content in its mixture with water at 30°C.
Linoleic acid was heated in the presence or absence of water in the temperature range of 200 to 260°C using a pressure-resistant batch reactor to examine the possibility of its conversion to conjugated isomers. The conversion occurred at very low yields, and the major products were the c9, t11 and t10, c12 conjugated linoleic acids. The t10, c12 isomer seemed to be produced more than the c9, t11, and the ratio of the isomers did not depend on both the temperature and the ratio of linoleic acid to water. When a dilute potassium hydroxide was used as the aqueous solution, the yield of the conjugated isomers was lower than that of the isomers in the mixture of linoleic acid with distilled water.