We examined the adverse effects of Taro tuber lectin administered to mice not by stomach intubation but by ad libitum feeding after being mixed into a basal casein diet. The aim of this work was to complete our studies on the in vivo nutritional effects of Taro tuber lectin on the growth of mice, and the effects on the physical activity and energy metabolism of mice which had ingested Taro tuber lectin. Crude and pure lectins were separately ingested for 6-9 days by ddY male mice weighing approximately 15 g, the average daily intakes being 142.1 mg of crude lectin and 71.5 mg of pure lectin. Body weight and food intake were recorded daily, and at the end of the experiment, the internal organs were weighed and the intestines observed under a light microscope. The results elucidated the mechanism by which the toxic effects of this lectin on physiological functions are brought about. The addition of this lectin to a diet resulted in the decreased absorption of dietary nutrients in the small intestine, and the resulting malabsorption. induced a reduction in food consumption, which was followed by growth retardation and a tendency toward diminished physical activity and energy metabolism. These results provide substantial evidence that this lectin is responsible, at least in part, for the nutritional inferiority of Taro tuber because of its interference with the intestinal absorption of nutrients.

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The relationship among MDA, TBA-reactive substances (TBA-RS) and tocopherols in the oxidation of soybean oil was investigated. MDA was determined by a new HPLC method with chemical conversion. When the soybean oil was heated at 170°C TBA-RS and MDA increased, the content of TBA-RS being approximately twice those of MDA. A correlation between the increase in MDA formed and the decrease in tocopherols was observed. When the oxidation of the oil was initiated by using 2, 2'-azobis (2, 4-dimethylvaleronitorile) at 40°C, TBA-RS dramatically increased during the initial stage and subsequently reached a plateau, little further increase then being observed. The relative ratio of MDA to TBA-RS was lower in the reaction performed at 40°C than that at 170°C. These results indicate that the increase of MDA was accompanied by the decrease of tocopherols, but that TBA-RS did not correlate with the change of tocopherols.

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The East Indian lotus rhizomes contained a comparatively small amount of galacturonic acid (about 213 mg in 100 g of immature lotus rhizomes and 233.5 mg in 100 g of the fully mature rhizomes). The galacturonic acid compositions of HCl-soluble pectin (pA), acetate buffer-soluble pectin (pB) and sodium hexametaphosphate-soluble pectin (pC) were 30.3%, 56.0% and 13.8 % in the immature lotus rhizomes, and 15.2%, 45.3% and 39.5% in the mature rhizomes, respectively. The degree of esterification of pectic polysaccharides in the immature lotus rhizomes was higher than that in the fully mature rhizomes. DEAE-cellulose column chromatograms of pA, pB and pC in the immature and fully mature lotus rhizomes were also different. The main neutral sugar of the pectic polysaccharides was galactose. After 1 hr of cooking, the immature lotus rhizomes became more softened than the mature rhizomes, and the amount of pA in the cooked immature tissue was greater than in the mature tissue. On the other hand, larger amounts of pB and pC remained in the mature lotus rhizomes than in the immature rhizomes. The mature rhizomes contained large amounts of pB and pC (low-methoxyl pectins) which were difficult to break down in a hot neutral solution by trans-elimination, making the mature rhizomes more difficult to soften during cooking than the immature ones.

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To investigate the cause of difficulty in the thermal maceration of bamboo shoots (monocotyledonous plant), pectic polysaccharides extracted with a sodium oxalate solution from bamboo shoots were compared with those from Japanese radish roots (dicotyledonous plant) and asparagus (monocotyledonous plant). Japanese radish roots and asparagus were completely macerated after heating with the sodium oxalate solution (pH 4.0) for 1 hr. Conversely, bamboo shoots maintained considerable firmness after being heated with the same solution 10 times for 1 hr each, but they easily were macerated when soaked subsequently in a 0.1 N sodium hydroxide solution at room temperature for 24 hr. The bamboo shoots contained a smaller amount of uronic acid than the Japanese radish roots and asparagus, while the pectic polysaccharides in the bamboo shoots contained a comparatively large percentage of neutral sugar. DEAE-cellulose column chromatograms of the pectic polysaccharides in these vegetables and those after alkaline saponification were different from each other. When the pH of the polysaccharides extracted with a 0.1 N sodium hydroxide solution after sodium oxalate extraction was adjusted to 4.0, those polysaccharides with a comparatively large percentage of galacturonic acids precipitated, this pectic polysaccharide containing a comparatively large percentage of xylose. The fact that the bamboo shoots contained this pectic polysaccharide, which was difficult to extract with the sodium oxalate solution, seems to be one of the causes of difficulty in thermally macerating bamboo shoots.

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Carbohydrates in Gobo (edible burdock, Arctium lappa L.) and Yamagobo (Goboazami, Crisium dipsacolepis Matsum.) were compared in triturated, defatted samples. Fractionation of the carbohydrates, and the sugar composition and sugar-linkage composition analyses of the fractions suggested that their basic constituent polysaccharides were almost the same. Gobo and Yamagobo both contained fructan as a reserve polysaccharide. The cell walls of Gobo and Yamagobo consisted of pectic substances (rhamnogalacturonan with neutral sugars), hemicellulose (arabinan, xylan, galactan, arabinogalactan and xyloglucan) and cellulose in the ratio of 53.6 : 8, 0 : 38.4 and of 55.8 : 7.2 : 37.0, respectively. The approximate ratio of fructan and cell-wall polysaccharides was 47 : 53 for Gobo and 66 : 34 for Yamagobo.

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Films of nylon 6 with a molecular weight of 9.8 × 10⁴ were drawn in a hot oven at 50°C or 180°C to desired ratios of up to 5 times and annealed at 180°C for 20 min. The maximum drawing ratio was hardly affected by the elongation conditions. The reason for this is analyzed in terms of the morphological aspects of the drawn films studied by wide-angle X-ray diffraction, small-angle X-ray scattering and small-angle light scattering. The reuslts are discussed in the context of the morphology and mechanical properties of commercial melt spinning fiber.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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