The recovery of isoflavones spiked into a soy sample at two different concentrations ranged from 94% to 105%. The multilaboratory validation study with 7 participating laboratories showed satisfactory interlaboratory precision; all HorRat values were < 2.Keywords: soy isoflavone, multilaboratory validation study, AOAC guideline IntroductionSoy contains isoflavone aglycones such as genistein, daidzein and glycitein, and their glycosides such as genistin, daidzin and glycitin (Munro et al., 2003). Recently, the antioxidant, cancergrowth inhibition, and other health promotion effects of soy isoflavones have been elucidated (Perabo et al., 2008, Cuevas et al., 2003, Nagata et al., 2002. A microbiota metabolite of isoflavone glycoside showed growth inhibitory activity for cancer cells and anti-inflammatory activity (Atkinson et al., 2005, Hirata et al., 2013, Shimoda and Hamada et al., 2011. Moreover, soy isoflavones are recognized to be plant estrogens, binding estrogen receptors to induce physiological effects. Japanese people consume isoflavones mainly from soy in everyday life; no other Japanese food contains such a high amount of isoflavones. The daily consumption of soy isoflavones is limited to 70~75 mg aglycone equivalent, as defined by the Food Safety Commission of Japan, because isoflavones are endocrine disruptors of human reproductive systems (Clarke et al., 2003). Therefore, it is important to analyze the isoflavone concentration in common foods and "food for specific health uses" rapidly and with high precision (Cederroth et al., 2012). However, the quantitative analysis of isoflavones by the official methods of AOAC international (OMA) 2001.10 and OMA 2008.03 is both time-consuming and requires a large amount of soy sample (i, Collison et al., 2008). With the OMA 2001.10 and OMA T. Ogita et al. 474 2008.03 methods, isoflavone content in soy samples can be quantified using 2 to 10 g of sample, and the analysis time by HPLC is 44.5 min and 63 min, respectively. Thus, the conventional method is not suitable for the analysis of large numbers of samples. Accordingly, the development of a better analysis method for quantification of isoflavones in soy samples is required.In this study, we developed a quantification method for soy isoflavones requiring shorter analysis time and less sample than the conventional method. ExperimentalChemicals Daidzin, daidzein, genistin, genistein, glycitin and glycitein were purchased from Nacalai Tesque (Kyoto, Japan) and used as the standards. All the chemicals were > 97% purity based on HPLC analysis. Soybeans (30 g) were frozen overnight at _ 80 ℃, and then ground using a Rotor-Speed MillP14 (Fritsch GmbH, Idar-Oberstein, Germany), passed through a 0.5 mm filter, and freeze-dried using a freeze dryer. Powdered soybean samples were thoroughly mixed, divided into 8 portions, and placed in plastic bags. Freeze-drying and mixing steps were repeated twice. Finally, soy powder samples were stored in aluminum laminated bags at _ 80℃. The soy powder particles were analyzed u...

Several proteins were extracted from the purified cell walls of suspension-cultured sugar beet cells with 0.5% EDTA (pH 6.8) after prior extraction of the walls with 0.5% deoxycholate and then with 2 molar NaCI. Two abundant proteins (P-I and P-Il protein) were separately purified to'homogeneity by procedures that included fractionation with ammonium sulfate, column chromatography on DEAE-cellulose and butyl Toyopearl, and preparative polyacrylamide electrophoresis. P-I exists as a dimer of identical subunits, and P-l1 is composed of four different subunits. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that quite different polypeptides are present in the culture medium and in the NaCI and EDTA extracts of the wall.

Starch content a#ects the taste, method of cooking and processing of potato tubers, and varies widely under di#erent growing conditions. In order to enable the introduction of sorting machines based on the starch content of potato tubers, we investigated nondestructive determination of starch content using visible and near-infrared (NIR) spectroscopy under practical conditions. Potatoes were placed on a conveyor system and a photometric sensor was continuously applied. Using potato tubers of various sizes and varieties, partial least squares (PLS) regression was carried out relative to starch content as measured by specific gravity to the second derivative spectra. The standard error of prediction (SEP) for starch content of !Danshaku-imo', !Mayqueen' and !Kita-akari' varieties were *.21῍, *./2῍ and *.20῍, respectively. Accuracy of prediction was slightly a#ected by di#erences in growing locations, by mud adhering to tuber surfaces, and by the temperature of tubers. It is concluded that the visible and NIR transmittance method is e#ective for accurate and rapid selection of potato tubers based on starch content and could thus be used in packinghouses.

For efficient research into breeding, cultivation, storage and marketing of vegetables, objective methods of quality evaluation are needed. Texture (Firmness) is the most important factor in evaluating the quality of Japanese radish (Raphanus sativus L.) root. We proposed a firmness evaluating method of fresh and lightly-pickled radish roots using a Texture Analyzer in the following way. Disks (10 mm in diameter and 5 mm thick) were obtained from the defined positions of radish roots of various cultivars and compressed using a cylindrical probe, then the destructive force was measured by the texture analyser. The measured forces correlated with firmness scores in the sensory evaluation. When there was more than 13 N difference in the destructive force needed for disks prepared after pickling radishes of different cultivars, the difference in firmness was also detectable by the sensory test. There was a considerable difference in the destructive force needed for the disks between cultivars, which was correlated with the concentrations of pectin and alcohol insoluble solids in radish tissue.

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