We identified an antimutagenic fraction in acetonitrile extracts from salted radish by Ames assay. One of the active compounds was identified as palmitic acid by NMR and GC-MS. Quantitative analysis of fatty acids was performed in salted radishes and commercial takuan-zuke. The major fatty acids were identified as α-linolenic, linoleic and palmitic acid, while the minor fatty acids were identified as palmitoleic, stearic, linoleic, oleic and (Z)-vaccenic acid. Total acyls in dried takuan-zuke were 274-680 μmol/100 g, and total acyls in salted radish were 124-357 μmol/100 g. During dehydration and salted aging, the ratio of free fatty acids to total acyls increased. While the fatty acid composition of dried radish products was equivalent to that of fresh radish, the ratio of polyunsaturated fatty acids of salted radish products was relatively low. The major fatty acids from salted radish showed antimutagenic activity against 2-amino-3-methylimidazo[4,5-ƒ]quinoline (IQ) and 4-nitroquinoline 1-oxide (4NQO) on Ames and umu tests. The results for inhibitory activity against IQ on the umu test were more sensitive than on the Ames test. The antimutagenicity of (Z)-vaccenic acid was greater than that of other fatty acids in the 4NQO-Ames test system, and the ED 50 (50% effective dose) value was estimated to be 2.8 nmol/plate.

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Gamma-aminobutyric acid (GABA) is a non-protein amino acid with several physiological functions, including hypotensive and tranquilizing effects. In this study, thin-layer chromatography was used to select 18 strains of lactic acid bacteria, out of 218 strains isolated from dairy products, for high GABA productivity. GABA production by the 18 strains was measured using HPLC, with strain 1056 showing the highest GABA productivity (6.95 mg/mL). This strain was identified as Lactobacillus brevis by morphological, physiological and genetic analyses. Lb. brevis 1056 produced GABA when it was cultured in media adjusted to an initial pH of 4.0-8.0, rather than 3.0. GABA production by strain 1056 increased with increasing amounts of glutamate (substrate) added to the medium (pH 5.0). It was also shown that GABA production by strain 1056 was faster than the other strains. These results suggest that Lb. brevis 1056 is a useful starter for GABA-rich functional foods. Lastly, as a model functional food, fermented chicken sauce was prepared using Lb. brevis 1056, and sufficient amounts (1.51 mg/mL) of GABA were produced in the sauce.

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Yacon (Smallanthus sonchifolius) root is regarded as a functional food material because it contains polyphenol-rich antioxidants, fructooligosaccharides, and dietary fiber. The taste of fresh yacon root is similar to that of pear, juicy and sweet. However, a peculiar astringency is also perceived in yacon root. When astringent persimmon is exposed to ethanol (EtOH) vapor, the astringency is removed. This process is recognized as being effective for astringency removal. In this study, we applied EtOH vapor treatment for removing yacon root astringency. During vapor treatment, yacon was kept in a small chamber (3 L) containing 20 mL of 10-90 % EtOH solution at 20°C under darkness. The removal of astringency was evaluated using decreases in soluble tannin concentrations in treated yacon juice. After 48hr of 30 % EtOH vapor treatment, the amount of soluble tannins decreased to ca.14 %. Sensory evaluation revealed improvement in the smell, texture and taste. Moreover, the antioxidative activity and the fructooligosaccharide composition in the juice were retained through the treatment period. Antioxidative activity was maintained at levels above 97 %, and changes in fructooligosaccharide composition were minimal. In conclusion, we confirmed that the astringency of yacon root could easily be removed, with the treated root maintaining a healthy function.

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Stable isotope ratios are potentially useful to discriminate the area from which plants and animals originate, and have, therefore, been applied for the chemical discrimination of the geographic origin of food materials. In this study, the isotope ratios of carbon, nitrogen and oxygen were determined for two brands of Japanese beef, Matsuzaka and Hida, in order to evaluate whether or not isotopic discrimination is applicable for beef brands. The isotope ratios of nitrogen and oxygen show similar values between the two brands, whereas that of carbon from Hida is clearly higher (by ∼4‰) than that from Matsuzaka. These results are consistent with the significant differences in plant species comprising the fodder and its blend ratio (e.g., C3 vs. C4) between these two brands. Thus, a distinctive isotope ratio profile could potentially be found for beef brands, which should be useful in the chemical identification or discrimination of beef brands.

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In this study, we investigated the anti-hypertensive effects of two enzymatic hydrolysates of chicken and pig collagens in spontaneously hypertensive rats (SHR). SHR were divided into three groups and administrated collagen peptides at 3 g/kg body weight, or water for 14 weeks. In the chicken collagen peptides group, systolic blood pressure was significantly reduced when compared with the control group, and diastolic blood pressure was also reduced when compared to the pig collagen group. Microscopic analysis revealed that inflammation in liver and heart was mildly ameliorated in the chicken collagen peptides group.

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The tuberous root of yacon (Smallanthus sonchifolius) is a rich source of fructooligosaccharide (FOS), which has a prebiotic effect. However, FOS significantly decreases accompanying (or FOS significantly decreases with) an increase in fructose during cool storage of harvested tuberous roots under normal pressure. The aim of this study was to investigate whether a storage condition at low temperature under reduced pressure could maintain FOS content by suppressing carbohydrate metabolism. After storage at 4°C for one month, FOS in the tuberous roots stored at 0.7 atm was effectively retained. In addition, the activity of two endogenous enzymes associated with the degradation of FOS and sucrose, fructan 1-exohydrolase and invertase, respectively, was markedly suppressed at 0.7 atm. These results suggest that low-pressure storage is an effective condition for long-term preservation of FOS-rich yacon tuberous roots.

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