The effect of maltotetraose (G₄)-rich corn syrup on fecal microflora in seven healthy men was examined. The participants were given daily experimental drinks containing 30g of G₄-rich corn syrup powder (G₄; 50%, W/W) for 10 days. The results obtained were as follows: 1) During feeding with the G₄-rich corn syrup, the volunteers never had diarrhea or flatulence. 2) There were no significant differences in fecal pH value. 3) Among the predominant intestinal bacteria, i. e., Bifidobacterium, Bacteroidaceae, Eubacterium and Peptococcaceae, there were neither changes in bacterial count nor proportion in feces. However, the populations of Enterobacteriaceae and Clostridium decreased and the Veillonella population increased. 4) The population of C. perfringens was decreased to below the detection limit. These results indicated that feeding with G₄-rich corn syrup inhibited the growth of intestinal putrefactive bacteria such as C. perfringens and Enterobacteriaceae, and it was also suggested that G4-rich corn syrup was effective for the improvement of colonic conditions.

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Weanling rats, suckled by dams fed an essential fatty acid-deficient diet (EFA-DEF diet) during their lactatian period, were classified into five groups based on the ratios of γ-linolenic to α-linolenic acid (1/4-GLA, 4/1-GLA) and linoleic to α-linolenic acid (1/4-LA, 4/1-LA) added to the EFA-DEF diet. After five weeks, the graups shawed similar liver and brain weights. The tatal lipid cantent in the liver of rats fed only the EFA-DEF diet was higher than that of the other groups. Although no significant differences in the contents of total phospholipid, phosphatidylethanolamine and phosphatidylcholine in the liver and brain were shawn among the five groups, the fatty acid composition of liver phospholipids varied with the experimental diets to a certain extent. As to fatty acids in phosphatidylethanolamine of rat liver, a remarkable increase in the proportion of total ω-3-series acids following the 1/4-LA diet, and in ω-6-series acids following the 4/1-GLA diet were observed. Total ω-6-series acids were significantly increased to a greater extent by γ-linolenic acid than by linoleic acid in the diets of each ratio. It was shown that γ-linolenic acid was more readily converted into dihomo-γ-linolenic acid and arachidonic acid than linoleic acid, while a large amount of γ-linolenic acid in the diet caused a decrease of ω-3-series acids in phospholipids, similar to the effect of α-linolenic acid o n ω-6-series acids. The learning ability of rats tested with the water-filled rnultiple T-maze tended to improve during the experimental period, although no statistically significant differenCe was shown among the five groups.

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The effects of dietary fiber on histological changes in the gastrointestinal tract of rats were studied. A fiber-free diet was supplied for 17 days to a control group and a diet containing 2% rice bran hemicellulose (RBH), high-methoxylated pectin (HMP), or microcrystalline cellulose (MCC) was given to one of three other groups. Weight gain and feed efficiency were greater in the dietary fiber groups than in the control group. Light microscopy (LM) and scanning electron microscopy (SEM) were used to examine the structural changes in the alimentary tract after these dietary manipulations. Mild swelling of the villi was observed by LM in the jejunum of rats fed the 2% RBH and HMP diets. Irregular villi were found by SEM in the jejunum and ileum of rats fed the water-soluble dietary fiber, especially HMP. Swelling at the villus tips was revealed by LM throughout the small intestine of rats fed MCC. The present results suggest that the structural modifications induced by a 2% level of these dietary fibers did not affect the functional characteristics of the gastrointestinal tract because weight gain and feed efficiency were greater in the dietary fiber groups than in the control group.

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The distribution and structure of enteroglial cells in the nerve plexuses of the guinea pig stomach were studied immunocytochemically using antiserum to S-100 b protein. Sections and whole-mount preparations of the submucous coat and longitudinal muscle layer of the stomach were immunostained by the peroxidase-antiperoxidase method. S-100 b protein-immunopositive enteroglial cells were demonstrated in the mucous coat, submucous coat, circular muscle layer, longitudinal muscle layer and serous coat. The nerve plexuses in the stomach constituted a three-dimensional network consisting of ganglia, nerve strands and an autonomic ground plexus, whose framework was formed by enteroglial cells. The submucous plexus contained a few small ganglia, whereas the myenteric plexus contained many large ganglia. In the larger curvature, the network of the myenteric plexus was more dense in the pyloric region than in the corpus ventriculi region.

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Cyanoepithioalkane (GETA) -producing activity in seeds and seedlings of 22 varieties of cruciferous vegetables was studied using 3-butenylglucosinolate as a substrate. Also, the correlation of CETA-producing activity with the activity of myrosinase (thioglucoside glucohydrolase, EC 3, 2, 3, 1) was investigated along with the effects of pH and temperature on both activities. All plant materials examined had various levels of CETA-producing activity, of which higher levels were detected in seeds and 8-day-old seedlings of Brassica oleracea L., B. juncea Coss and Raphanus sativus L., and lower levels in those of B. campestris L. Although seeds and 4-day-old seedlings showed relatively higher coefficients of correlation between CETA-producing activity and myrosinase activity, the correlation was considerably low in the case of 8-day-old seedlings. The effects of pH and temperature on the two enzyme activities, which were assayed using an enzyme extract prepared from 4-day-old seedling of Ohba-Takana (B. juncea Coss), were different. The optimum pH and temperature for CETA-producing activity were pH 6.0 and 15-25°C, whereas those for myrosinase were pH 6.6-7.8 and 45-55°C, respectively.

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Extrusion cooking of whole soybeans was performed under high-temperature and low-moisture conditions with a twin-screw extruder (Model: Alpharizer 100, Suehiro Iron Works, Yokkaichi, Japan). Extrusion, proceeded under the following conditions: screw diameter, 89mm; L/D=12; screw rotatioa speed, 120rpm; temperature at die plate, 239, 216 or 175°C, die diameter (4holes), 4mm each; water addition rate, 10l/h (to make the feed moisture content 20%); feed rate, 125kg/h. Chemical changes in the components throughout the extrusion cooking were investigated and nutritional evaluation was carried out on raw soybeans and their extrudates. With regard to chemical and physicochemical properties, no change in amino acid or available lysine content was observed throughout the extrusion process. Trypsin inhibitor, lectin and urease activities were almost completely lost. Furthermore, it was found that the proteins in raw soybeans became insoluble. However, it was observed that the proteins decomposed into smaller components on SDS-PAGE. As for the nutritional properties, the proteins in the extrudates were more digestible by pepsin and trypsin than those in raw soybeans. Moreover, the nutritional characteristics (PER, BV and NPU) of the proteins were significantly improved by the process. These results indicate that the extrusion cooking of whole soybeans under the conditions employed in this study does not have any adverse effects on the nutritional value of the beans.

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“Okara” (OC), a by-product of the “tofu” industry, was fermented with Rhizopus oligosporus (a fungus for making tempeh) in order to improve it as a high-fiber, low-energy foodstuff. R. oligosporus cells proliferated to form a network in cavities within the soybean cells. The OC fermented with R. oligosporus (OT) contained more free amino acids, acid-soluble nitrogen, free sugars and inorganic hosphorus, and less fiber than the control. The fermentation resulted in degradation of some constituents of OC into low-molecular-weight materials and an improvement of their digestibility. Chemical analysis revealed that the dietary fiber content of OT was more than 50%, and its energy content half that of wheat flour. Also, the waterholding and emulsifying capacities, oil-absorbability and antioxidant activities of OT were higher than those of OC. These results indicate that OT could be useful as a high-fiber, low-energy food material.

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The contents of pectic substances, metal elements, organic acid and the hardness of 'Takada bungo' plums (Prunus mume SIEB. et ZUCC.) were analyzed for about 1 month from the end of May to the beginning of July, 1987, and the results were investigated in relation to harvest time for the processing of the fruit into Ume-Zuke, or pickled plum. The results obtained were as follows: (1) The calcium content of ethanol-insoluble substances prepared from the plums changed little until the middle of June, but decreased gradually with fruit growth. (2) The ratio of HSP (hexametaphosphate-soluble pectin) to TP (total pectin) showed little change with fruit growth, but exhibited a decrease after the middle of June. On the other hand, the ratio of HWSP (hot water-soluble pectin) to TP changed little with fruit growth, but showed an increase after the middle of June. (3) Malic acid content of plums reached a maximum in the middle of June and decreased markedly with fruit growth, whereas the citric acid content of the plums increased gradually with fruit growth, followed by an appreciable increase after the middle of June. (4) Ume-Zuke processed using plums harvested after the last ten days of June had a softer texture. From these results, it was concluded that the increase in citric acid occurring during fruit growth gives rise to chelate binding of divalent cations combined with pectic substances, and that the release of these divalent cations, changing HSP to HWSP to some degree, consequently causes a decrease in the hardness of texture of Ume-Zuke.

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Comparisons were made of the effects of oxidized fatty acids (OFA, fatty substances insoluble in petroleum ether) and dimers (polymerized fatty acid fraction), and their secondary products (SP) of fatty acids separated from heated soybean oil, on the decomposition of tocopherol, several amino acids (valine, methionine, tryptophan, histidine, cysteine and arginine) and ascorbic acid in ethanol solution during oxidation at 60 or 20±2°C. The decomposition of tocopherol, amino acids (especially cysteine and histidine) and ascorbic acid was apparently promoted by OFA and SP. The decomposition ratio of these components increased with further addition of OFA and SP. The effect of SP on the decomposition of tocopherol, amino acids and ascorbic acid was similar to that of OFA. As reduction of nitroblue tetrazolium was observed upon addition of SP or OFA, it was considered that the oxidation of tocopherol, amino acids and ascorbic acid by OFA and SP might be attributable to the production of superoxide anion.

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The antiscorbutic effect of Actinidia polygama Maxim. tea on guinea pigs was investigated by measuring body weight gain and ascorbic acid (AsA) contents of the liver, adrenal glands and spleen. The results were as follows: 1) The body weight gain in AsA-supplemented groups was almost the same as that in Actinidia polygama Maxim. tea-supplemented groups. 2) When the AsA dosage given to guinea pigs was the same as the amount of total AsA in Actinidia polygama Maxim. tea, the AsA content in the organs of the AsA-supplemented groups was similar to that in the tea-supplemented groups. 3) Although the AsA-deficient animals did not show any significant difference in final body weight gain compared with the other groups, a very small amount of AsA was found in all three organs (liver, adrenal glands and spleen) investigated.

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