“Tanbaguro” (Glycine max) is a local variety of Japanese soybean characterized by a large seed size and black seed coat. We examined a method to distinguish Tanbaguro seeds, which were maintained and managed in domestic production as the standard strains, from seeds of other black soybean varieties. We selected 18 pairs of soybean simple sequence repeat (SSR) primers as primer sets to distinguish the seed varieties. Our analysis revealed that 4 strains and 20 seeds cultivated in Japan and distributed as Tanbaguro exhibited total agreement with standard strains, while 12 strains and 60 seeds cultivated in China and distributed as Tanbaguro exhibited only 13% agreement. These results suggested a wide genetic diversity of black soybeans cultivated in China. We then confirmed that our identification method using the same 18 primer sets can also be applied to processed foods. Identification of Tanbaguro products that were boiled, steamed and roasted was as successful as that of seeds ; the method could not be applied to fermented (natto) Tanbaguro products. Analysis of commercially processed foods containing Tanbaguro indicated that some foods of unknown source included soybeans cultivated in China, confirming that these foods are mixtures of Tanbaguro standard strains and other varieties.

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The effect of a binary mixture of antioxidants on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was investigated using 11 antioxidants as food additives or 24 natural antioxidants. Among 55 combinations of binary mixtures, including 11 antioxidants, BHA, BHT, catechin, quercetin, sesamol, ferulic acid, gallic acid, morin, ellagic acid, α-tocopherol, and δ-tocopherol, the DPPH radical scavenging activity of 36 combinations were significantly greater than the expected activity of individual antioxidants, resulting in synergistic effects. Also, one combination showed antagonistic effect. Among 276 combinations of 24 natural antioxidants, including 4 benzoic acids, 3 cinnamic acids, 12 flavonoids, 2 vitamins, and 3 diterpenes, 74 showed synergistic effects and 61 showed antagonistic effects. However, the ratios of the actual to expected activity of many synergistic and antagonistic combinations were about 1.1-1.2 and 0.8-0.9, respectively.

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We conducted a placebo-controlled, double-blind 4-week study on the oral intake of either 3 doses of scaled collagen hydrolysate (2.5g, 5g and 10g), pig skin collagen hydrolysate (10g) or placebo in 214 healthy female volunteers (mean age, 34.1±SD 5.9 years). The volunteers were divided randomly into 5 groups and their skin condition was measured before and after ingestion. The moisture content of the stratum corneum of the cheek showed a significant increase after 4 weeks in all the groups taking the hydrolysates, while it showed a dose-dependent improvement in groups taking collagen hydrolysate (2.5g-10g). A stratified statistical analysis of subjects >30 years old showed significant differences in the groups taking 5g or 10g of hydrolysates (P<0.05), compared with the placebo group. There were no significant differences in transepidermal water loss, viscoelasticity or cutaneous findings between any of the groups. These results indicate that the major change following oral intake of collagen hydrolysate is an improvement in the moisture content of the stratum corneum.

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The morphology and physical state of tissue water of cucumber fruit were examined by magnetic resonance imaging (MRI) and compared using a 1-Tesla (T) permanent magnet that was devised for food research and a 7-T high-resolution magnet. Then, the distribution and mobility of water were analyzed between tissues by the relaxation time-weighted imaging methods. Sarcocarp, placentas, seeds and vascular bundles of the fruits in different physiological conditions were distinguishable by 1-T small MRI, while clear morphology was observed by 7-T high-resolution MRI. However, while low mobility of water in the tissues of low water content, such as the placentas, was not detected due to the fast T₂ decay of the signals in the high magnetic field of 7-T MRI, it was detected by 1-T MRI, which had slower T₂ decay of the signals. Moreover, the T₁ signal recovery was faster in the 1-T MRI than in the 7-T MRI. These results indicate that the small 1-T MRI is suitable for analyzing the physical conditions of water in respect to the detection of the low mobility of water and also for obtaining a strong T₁ contrast of morphology despite the lower quality of the images compared to the high-resolution images. The 1-T small MRI is therefore an effective method for studying the properties of food materials with a wide range in the amount and mobility of water.

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The aim of the present study was to utilize salmon bones, by-products of salmon processing, as a calcium supplement. We examined the effects of processing methods of salmon bones, especially degrees of pulverization and refining, on calcium absorption using a rat balance study (5-week-old male Sprague-Dawley rats). Using different pulverization and refining conditions, salmon bone powders were prepared and added to test diets based on mineral formulation of the AIN-93G diet. We found that ultrafine pulverization of salmon bones improved calcium absorption in rats and that semi-refined salmon bone powder, i.e., materials containing calcium with a large amount of salmon bone protein, had the potential to enhance calcium absorption. Thus, salmon bone may be an excellent resource for a calcium supplement, and the ultrafine pulverization and preparation, including that of bone protein, can enhance bioavailability of salmon bone calcium.

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Variation in mineral composition of commercially available Nanbu-senbei (with sesame seeds or peanuts) and comparison of their contents with those in the Standard Tables of Food Composition in Japan were determined for 9 minerals, Na, K, Ca, Mg, P, Fe, Zn, Cu and Mn. Nanbu-senbei was collected from Morioka, and its mineral composition was measured and compared with the calculated values obtained from the Standard Tables. The measured mineral concentrations in commercially available Nanbu-senbei were higher than the calculated values. In Nanbu-senbei with peanuts, the mineral composition was affected by the main and side ingredients. In Nanbu-senbei with sesame seeds, the ash content was significantly higher than the calculated values and significant positive correlations between measured and calculated values of Mg, Ca, P, Zn, Cu and Mn were observed.

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To elucidate the relationship between the heating method and the changes in phenolic compounds in a potato, a potato was heated by either aqua-gas (superheated steam containing micro-droplets of hot water), superheated steam, hot air or boiling. More phenolic compounds were stable in the aqua-gas heating and boiling methods, compared to the other methods. Further modeling of each method revealed that the temperature profile was related with the stability of phenolic compounds during the heating process. Phenolic compounds in the potato tissue decreased around 60-80°C, indicating reactions between these compounds and polyphenol oxidase (PPO). Phenolic compounds and PPO reactivity was localized on the outer portion of the potato. These results indicate that more phenolic compounds can be retained in the heated potato when the surface temperature rises to higher than 80°C rapidly.

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The hypocholesterolemic activities of Lactobacillus and Pediococcous isolated from Funazushi, a fermented-fish product, were evaluated with in vitro and in vivo assay systems. Among viable cells, we selected Lactobacillus plantarum NLB136 for its strong cholesterol and bile acid binding abilities, as well as for its tolerance against a simulated gastric juice and its lack of bile acid deconjugation activity. Among the heat-sterilized bacteria, we selected L. paracasei NLB162 and NLB163 for their strong cholesterol and bile acid binding abilities. The heat-sterilized L. paracasei NLB163 showed the strongest hypocholesterolemic activity in cholesterol-fed mice, indicating that the heat-sterilized L. paracasei NLB163 could be a new functional food material with hypocholesterolemic efficacy.

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Hypocholesterolemic effects and safety of capsules containing heat-sterilized Lactobacillus paracasei NLB163 isolated from Funazushi (NLB163 capsule) were investigated in a double blind, placebo-controlled, parallel design trial. The subjects included adult males and females with boundary and mild hypercholesterolemia (serum total cholesterol level=202-268mg/dL, serum LDL cholesterol level=121-180mg/dL), who were not taking hypocholesterolemic medicine. Subjects were randomly divided into the NLB163 and placebo groups and given NLB163 capsules (containing 100mg of heat-sterilized L. paracasei NLB163 powder) and placebo capsules, respectively, at doses of 2 capsules 3 times a day for 6 weeks. NLB163 capsule intake significantly decreased the serum levels of total cholesterol by 9.4% (p<0.01) and LDL cholesterol by 13.2% (p<0.05), whereas placebo capsule intake showed no significant changes ; these levels decreased in most subjects of NLB163 group. Moreover, no hematological, blood biochemical, physical, or clinical change indicative of an adverse reaction was observed following NLB163 capsule intake. These results demonstrate the benefits and safety of L. paracasei NLB163 in subjects with boundary and mild hypercholesterolemia.

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[in Japanese]

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