Most of the chemical problems associated with the production of pickles from vegetables have been elucidated, and the technology of pickle production to suit the tastes of modern consumers has been systematized on the basis of chemistry. The most important consideration is the low content of salt and the texture of vegetables and preservation of fragrance during the pickling process. Thus, efforts have been made to popularize the production of pickles using refrigerators or chillers. As for pickled radish, formation of the yel1ow intermediate compound β-carbolyn due to complex bonding of decomposition products of the hot component of radish, “4-methylthio-3-butenyl isothiocyanate” during pickling, and formation of the low-molecular-weight sulfur fragrance are suppressed. Seasoned pickles preserved in 20% sodium chloride during the optimum season for vegetables, and then desalted in a refrigerator, are low-salt pickles, and we have succeeded in developing “fresh pickled vegetables preserved in salt” with abundant vegetable taste to avoid desalting.

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The effects of dietary P intake and testosterone secretion on Ca, Mg and P metabolism were investigated in weanling male Wistar rats. The rats were divided into two groups, and one group was orchiectomized 4 days before administration of an experimental diet. The rats were then fed two levels of P (0.5% and 1.5% P) in the diet for 24 days. Dietary P levels were controlled with K5P3O10. Both intact and orchiectomized rats fed a high-P diet showed a decrease of urinary Ca excretion in the 5 days before dissection. Contents of renal Ca, Mg and P were increased by feeding the high-P diet and orchiectomy. Orchiectomy decreased the concentration of Mg and P, but not that of Ca, in serum. No effects were observed on contents of Ca and P per gram of dried femur. Furthermore, the concentration of serum parathyroid hormone was increased, whereas urinary excretion of cAMP was decreased, in rats orchiectomized and fed a high-P diet.

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We recently reported that porcine plasma peptides affected serum lipids levels in rats. The present study was conducted to investigate the mechanism of improvement in lipid metabolism by porcine plasma peptides. Male Wistar rats were fed a 25% casein diet (casein group), or a porcine plasma peptide diet in which half of the casein was replaced by porcine plasma peptides (peptide group), or an amino acid diet in which half of the casein was replaced by an amino acid mixture identical to the amino acid composition of the porcine plasma peptide (amino acids group). All the animals were fed the experimental diets ad libitum for two weeks. Serum and liver lipids, urinary nitrogen and fecal cholesterol excretion were then determined. The serum total cholesterol level in the peptide group had a tendency to be lower than that in the casein group, and that in the amino acids group was decreased significantly compared with the casein group, but there was no significant difference between the peptide group and the amino acids group. The TBA values of both serum and liver in the peptide group were decreased significantly compared with the casein group. These results suggest that the serum total cholesterol level is affected by dietary amino acid composition, and that the TBA value is affected by the form of peptide.

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Effects of dietary cod liver oil (Gadus macrocephalus, CLO) and pollack liver oil (Theragra chalcogramma, PLO) on serum and liver lipids were investigated in rats fed low-protein diets (5% wheat gluten). Male rats were fed diets consisting of 10% fish oils or 10% corn oil (control, CO) for 7 weeks. The body weight gains in the CLO group were significantly decreased in comparison with those in the control and PLO groups. Serum total lipid and cholesterol concentrations in the fish oil groups were significantly lower than those in the CO group. Nonesterified fatty acid (NEFA) and TG (Triglyceride) concentrations in the serum were decreased significantly in the PLO group. Histologically, fatty liver was much more severe in the PLO group than in the CLO or control group.

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The absorption and metabolism of β-carotene by rat inverted small intestine were studied in situ. First, an assay system of β-carotene absorption and retinol production was established. Simultaneous use of NADH and NA in the incubation mixture was required for good β-carotene absorption. The pH optima of both β-carotene absorption and retinol production were the same, 7.7. Ten millimolar Na-cholate was required as a β-carotene solubilizing agent. Saponification was necessary in this assay system, because retinol ester was a major product, followed by transportation from the intestine to the incubation mixture. When new parameters, total β-carotene absorbed and total retinol produced, were introduced, the concentration of the substrate β-carotene had a great influence on the absorption rate of β-carotene (38-69nmol/g intestine·h) and also the production rate of retinol (14-36nmol/g intestine·h). The absorption ratio decreased with increasing concentration of the substrate β-carotene, and the ratios were 10.8%, 5.7% and 4.3% at 15, 30 and 70μM β-carotene, respectively. The production ratio of retinol from β-carotene absorbed increased from 15% to 75%, depending on the amount of β-carotene absorbed. These results indicate that a major proportion of β-carotene absorbed is rapidly cleaved, followed by production of retinol through retinal, suggesting the possibility that β-carotene is cleaved at the center site of the isoprenoid structure.

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Mineral status and plasma biochemical parameters in rats with rubidium depletion were studied. The supplemental level of rubidium was based on the rubidium concentration found in commercial animal diets. Male Wistar rats, 4 weeks old, were fed a rubidium-supplemented (8.12mg Rb/kg) or nonsupplemented (0.54mg Rb/kg) diet for 11 weeks. Compared with the rats fed the rubidium-supplemented diet, those fed the rubidium-nonsupplemented diet had a lower rubidium concentration in their tissues. They showed higher potassium levels in plasma, kidney and tibia, but a lower level in testis. They had a lower phosphorus level in heart and spleen, a lower calcium level in spleen, and a higher magnesium level in tibia. They had a higher urea nitrogen level in plasma. These results suggest that the rubidium concentration in tissues reflects rubidium intake, and that rubidium depletion affects mineral (potassium, phosphorus, calcium and magnesium) status.

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The effect of Tochu (Eucommia uimoides, Tu-Chung in Chinese) leaf powder on lipid metabolism, particularly cholesterol metabolism, was investigated. As an animal model, stroke-prone spontaneously hypertensive rats (SHRSP) fed a high-fat and high-cholesterol diet (HFC diet) were used to induce hypercholesterolemia. The experimental group was given the HFC diet containing 5% Tochu leaf powder by weight for 2 weeks with free access to the diet and water. The administration of Tochu leaf powder markedly prevented the elevation of serum total cholesterol. The hypocholesterolemic effect was due mainly to a marked decrease in the content of cholesterol in the very-low-density lipoprotein (VLDL) fraction, which was associated with decreases in the levels of apolipoprotein B (apoB) and apoE. These results suggest a decrease in atherogenic and cholesterol-rich VLDL produced by HFC diet feeding. In the liver, elevation of cholesterol content was also markedly prevented by administration of the Tochu leaf powder, whereas no significant change in the contents of phospholipid and triglyceride was observed. In addition, there was no significant change in the activities of microsomal cholesterol 7α-hydroxylase and acyl-CoA: cholesterol acyltransferase (ACAT).

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With the aim of developing useful health foods, an investigation was conducted on the effects on defecation of foods including shiitake mushroom (Lentinus edodes) as the main material. A mixture (SK-204) consisting of dried shiitake treated by wet-heating and fructo-oligosaccharides in a proportion of 7: 3 was prepared. When SK-204 was administered to rats, the water content of their feces was increased to 70% from 63% before administration, and softening of the feces was observed in half of the rats; however, no diarrhea was evident. From this result, it is suggested that SK-204 could be available as a potentially promising health food for regulation of defecation.

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