Stevia (Stevia rebaudiana), a well-known sweet herb, has been reported to have potent antioxidant activity. Methanolic extract of Stevia was fractionated and subsequently purified according to the results of DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay, producing three active compounds. Structural analysis of these compounds revealed that they were 3,4-dicaffeolylquinic acid, 3,5-dicaffeolylquinic acid and quercetin-3-O-α-rhamnopyranoside. Their antioxidant activity was measured using a radical initiator AAPH 2,2′-azobis(2-amidinopropane)hydrochloride -induced lipid oxidation system. While their activity was not as high as that of trolox, the three isolated compounds exhibited potent antioxidant activity at a concentration of 60μmol/l.

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Changes in the concentration of major phenolic compounds that occurred during growing, storing and processing of yacon (Smallanthus sonchifolius) were investigated from the viewpoint of effective usage of the functional ingredients in yacon. Major phenolic compounds, chlorogenic acid (1), 3,5-di-O-caffeoylquinic acid (2), 2,4- or 3,5-di-O-caffeoylaltraric acid (3), 2,5-di-O-caffeoylaltraric acid (4), 2,3,5- or 2,4,5-tri-O-caffe-oylaltraric acid (5), 4-O-caffeoyl-2,7-anhydro-D-glycero-β-D-galacto-oct-2-ulopyranosonic acid (6), and 4,5-di-O-caffeoyl-2,7-anhydro-D-glycero-β-D-galacto-oct-2-ulopyranosonic acid (7) had high DPPH radical scavenging activities. 4,5-Di-O-caffeoyl-2,7-anhydro-D-glycero-β-D-galacto-oct-2-ulopyranosonic acid methyl ester (8) occurred in the leaf and stem and was elucidated by MS and NMR spectroscopy. The concentration of compounds 1-8 peaked in the stem during the early stages of yacon growth. In the leaf, tuberous root, and tuberous stem, it peaked in the latter stage of growth. However it did not change during storage of the tuberous root. The phenolic compounds in yacon leaf and tuberous root were retained well by drying with hot air at 40-60°C, but most of them were lost at 80-100°C. About half of the phenolic compounds in yacon noodle prepared with the heat-treated yacon leaf powder were retained, but about 80% of phenolic compounds were lost in the noodle prepared by yacon leaf powder without heat treatment. The reduction in the concentration of phenolic compounds during processing yacon was assumed to be due to polyphenol oxidase.

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The effects of four edible mushrooms (Shiitake, Hiratake, Eringi, Hatakeshimeji) on serum and hepatic lipid levels were investigated in rats. The experimental diets were prepared by adding 10% (w/w) edible mushroom powder to a diet containing 20% fat and 1% cholesterol, and these were made freely available to male Sprague Dauley rats for 3 weeks. Body weight and food intake were recorded every 2 days, and serum and liver levels of triacylglycerols (TG), total cholesterol (TC), and phospholipids (PL) were analyzed at the end of the feeding period.
The results showed that the body weight and food intake of the four mushroom groups were significantly lower than those of the control group (p<0.05). The liver level of triacylglycerols was significantly lower in the Hiratake, Eringi and Hatakeshimeji groups than that in the control group. The serum cholesterol levels of the mushroom groups were also significantly lower than that of the control group (p<0.05). These results show that the four edible mushrooms suppress hepatic triacylglycerols accumulation, and lower blood lipid levels.

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Models for determining country of origin of one grain of black Tanbaguro soybean using inorganic element composition and linear discriminant analysis (LDA) were proposed and assessed for applicability.
Test samples consisting of 66 Tanbaguro varieties were collected from Japan and China. Approximately 100 grains of each type was ground to powder. Test samples of approximately 0.5g were digested with nitric acid using microwave digestor and 24 elements in the sample were determined by ICP-AES and ICP-MS. An LDA model for six of 24 elements (Ba, Ca, Mn, Nd, W, Ni) selected by backward stepwise regression could be used to correctly identify the country of production (Japan or China) of all 66 samples.
Ratios of inorganic element concentrations to potassium concentrations in samples were introduced to simplify pre-treatment. An LDA model using concentration ratios of the six elements (Ba, Ca, Mn, Nd, W, Ni) to potassium could be used to identify two countries.
The ratios of the six elements : K in one grain from each of the 97 samples (the 65 samples used to construct the LDA model and the 32 samples collected to validate the model) were analyzed in the same way and 97 samples were correctly classified to levels of approximately 84%. In addition, 97 samples were classified approximately 94% correctly using the LDA model with the ratios of the concentrations of three elements (Cd, Cs, V) selected from 15 elements (determined by ICP-MS) to that of potassium.

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We previously demonstrated that Hosobawadan was an effective anti-oxidative vegetable that contained anti-oxidative constituents such as D(+)-chicoric acid (ChA), chlorogenic acid (ChgA), caffeic acid (CA), luteolin 7-O-β-D-glucuronide (LU-gluc) and luteolin 7-O-β-D-glucopyranoside (LU-glc). In the present study, we first examined anti-LDL oxidative activity of Hosobawadan and found that the strength of anti-oxidative activity for LDL was dependent upon ChA, LU-gluc and LU-glc. This was due to ChA, which exhibited moderate activity and was abundant in Hosobawadan, with LU-gluc and LU-glc also exhibiting strong activity. We then examined the levels of these polyphenol compounds in rat plasma after oral administration of Hosobawadan extract (ChA 200mg/kg body weight). ChA was detected at the highest concentrations (2.9±1.6μg/mL) in the rat plasma 15min after oral administration. Conversely, luteolin (LU) was detected in rat plasma treated with glucuronidase/sulfatase, suggesting that LU in plasma existed as LU conjugates.

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We have developed five PCR-based DNA markers for rice blast resistance. All the DNA markers developed in the present study were shown to be located on the same chromosomes as the target blast resistance genes and are estimated to be closely linked with them. Using PCR for these primers, four typical Philippine rice cultivars were found to have different DNA patterns. Furthermore, we have developed a novel primer closely related to soluble starch synthase (SSSI). This primer revealed marked differences between Japonica and Indica subspecies of rice. In addition, the results of PCR were highly correlated with the amylose content. This is due to the close location of granule-bound starch synthase (GBSS) and SSI on rice chromosome six at an approximate map distance of 5cM. The PCR results for 14 typical Philippine rice cultivars also showed high correlation for the amylose content. The present authors developed a formula for estimating the amylose content and gel consistency by multiple regression analyses based on the results of PCR as the explanatory variables.

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For the purpose of investigating the influences of monovalent minerals on the sensory characteristics of milk, the physicochemical properties of milks composed of a mixture of two UHT nonfat milks, namely reverse osmosis membrane-treated milk and nanofiltration membrane-treated milk, were studied and a sensory evaluation of these milks was conducted by a panel of 31 experts. The nanofiltration membrane-treated milk had a lower monovalent mineral content and had a lower electrical conductivity than the reverse osmosis membrane-treated milk, but no differences were found between them in regards to their divalent minerals, lactose, and protein contents.
An evaluation of their sensory attributes and a principal component analysis of these attributes revealed the following results : the higher the proportion of the reverse osmosis membrane-treated milk, the higher the thickness of the nonfat milk, and the higher the proportion of the nanofiltration membrane-treated milk, the higher the thinness and the sweetness of the nonfat milk. Comprehensive evaluation of the palatability of the nonfat milks showed that nonfat milk composed of reverse osmosis membrane-treated milk and nanofiltration membrane-treated milk in a proportion of 2 : 1 was most preferred, and that moderate levels of saltiness and moderate thickness derived from the minerals in the milks were important factors for palatability.

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In order produce raw livestock visceral meat that can be eaten safely, the sterilization conditions for these meats by high pressure treatment rather than by heat treatment were investigated. Cell numbers in the range 10¹0⁷ of Escherichia coli, Salmonella and Staphylococcus aureus were inoculated in bovine liver, MINO (bovine first stomach), SENMAI (bovine third stomach), SHIMACHO (bovine colon), chicken liver and chicken gizzard. After the meats had been treated for a specified time and pressure at room temperature, the remaining bacterial cells were counted using the official assay method. Even Staphylococcus aureus, which is the most resistant to pressure, was not detected after treatment repeated six times for 10min under a pressure of 400 megapascal (MPa). In the case when bacterial cells were not inoculated, no bacterial cells were detected after treatment for 30min under a pressure of 300MPa. Assuming that pressure treatment results in higher safety than heat treatment, bovine liver, SENMAI, chicken liver and chicken gizzard were treated at high pressures of over 400MPa, and the sensory evaluation (significant difference test at 5% significant level) of eating raw visceral meats before and after treatment was carried out. The treatment at 400MPa resulted in a deterioration in the color, but did not affect the tenderness and tastiness of the meats. In the case of 500MPa, a deterioration in the color, tenderness and tastiness of the meats was observed.

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The effect of tamari soy sauce cake (tamari cake) on blood pressure in spontaneously hypertensive rats (SHR) was examined. The SHRs were fed an experimental diet for 28 days and their systolic blood pressures were measured by the tail cuff method. The rats fed diets containing desalted tamari cake at a level of 10% and 20% showed a significantly lower blood pressure compared to the control group (tamari cake free). The preparation of ACE inhibitory fractions (FI and FII) from tamari cake utilized alkali extraction, followed by chromatography on Diaion AMP 01 and Toyopearl HW-50F. The concentrations of FI and FII producing 50% inhibition of ACE activity were 0.99 and 0.19mg/ml, respectively. Single dose oral administration of FII (0.03g/kg of rat weight) in SHRs showed a significant reduction in systolic blood pressure of 19.8mmHg at 24h after administration. These results suggest that FII lowered systolic blood pressure by suppressing ACE activity.

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[in Japanese]

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