In order to utilize the isoflavone of soybean, which is expected to have higher functionality, we investigated changes in composition and behavior of isoflavone conjugates of soybean following rehydration with different temperatures, duration of and heating rates. The conditions were selected in consideration of home cooking processes and industrial processes, and 12 isoflavones were analyzed by HPLC. For 12-hour rehydration at 5, 20 and 30°C, the composition of isoflavones was nearly identical to that before rehydration. With rehydration at 40°C, malonyl-glucosides decreased 13% and aglycon increased slightly, and at 60°C rehydration, malonyl-glucosides decreased 54%, and daidzein and genistein of aglycons increased 10-and 12-fold, respectively. Besides increasing aglycon at rehydration at 60°C, daidzin and genistin of glucosyl-glucosides increased 2.5-fold. For rehydration time of 24 hours, these trends became more pronounced. The isoflavone composition of soybeans cooked for 1 hour at 60°C was similar to that for soybeans cooked at 95°C for 30°C/min with a 2°C/min heating rate. Malonyl-glucosides decreased slightly, equivalent to the increase in aglycons. With heating rates of 9°C/min and 30°C/min, malonyl-glucosides decreased 38% and 40%, respectively, and glucosyl-glucosides increased two-fold.

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The intake of antibodies in the diet is expected to improve intestinal flora and to have an effect against human pathogens, but reports in this field are scarce. We administered whey protein concentrate (WPC) that was rich in natural milk antibodies against human pathogens to healthy elderly volunteers and analyzed fecal flora by T-RFLP and FISH. T-RFLP data for the intestinal flora showed the presence of 29 bacterial operational taxonomic units (OTUs). The administration of milk antibodies for 3 weeks resulted in the reduction of OTU 369 (Clostridium cluster IV), OTU 469 (Bacteroides), and OTU 853 (Bacteroides), and the increase in OTU 366 (Bacteroides), OTU 443 (unidentified bacteria) and OTU 995 (Clostridium subcluster XIVa). Bifidobacteria and Lactobacilli were not influenced by the administration of milk antibodies. For FISH, fecal samples obtained for 8 weeks of WPC treatment were analyzed for bacterial counts by 16S rRNA hybridization. No effect was observed on number of total bacteria and Bifidobacteria were observed. However, numbers of E. coli, Clostridium difficile and C. perfringens decreased. In contrast, Lactobacilli, Bacteroides spp., Prevotella, and Bacteroides fragilis increased. Measurement of milk IgG in feces following administration of 320 mg of bovine immunoglobulin showed that 800μg (0.24%) was recovered. The influence of administration of milk antibodies on intestinal bacterial flora was discussed from the aspects of endotoxin translocation and improvement of rheumatoid arthritis.

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A rhamnan sulfate was extracted from green seaweed, Monostroma nitidum (Hitoegusa), which is commercially cultured on the coast of the Okinawa Island, Japan. The yield of rhamnan sulfate was 3.5% (W/W), and the total carbohydrate, uronic acid, ash, sulfuric acid and moisture of the polysaccharide was 67.2%, 11.8%, 27.3%, 24.7% and 3.5%, respectively. L-rhamnose (L-Rha), D-xylose (D-Xyl), D-glucose (D-Glc), D-galactose (D-Gal) and D-glucuronic acid (D-GlcA) residues were identified by liquid chromatography (HPLC), and the molar ratio of L-Rha : D-GlcA : D-Xyl : D-Glc : D-Gal : sulfuric acid for the polysaccharide was estimated to be 7.0 : 1.0 : 0.5 : 0.1 : 0.5 : 5.0. From the results of methylation analysis and NMR (¹H and ¹³C) studies of native and desulfated rhamnan, the polysaccharide was found to include (1→3)-linked α-L-rhamnopyranosyl residues on the main chain and β-D-GlcAp(1→2)-α-L-Rhap(1→2)-α-L-Rhap(1→linked trisaccharide side chains at the C2 position. The sulfate groups substituted at C4 and C2 position of the L-rhamnosyl residues on the main and side chain, respectively.

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Konjac (konnyaku in Japanese) gels in mini plastic cups are known to pose a choking hazard for children and elderly people, mainly due to the physical properties of the gels, including their tough, elastic texture. Addition of other hydrocolloids can modify the physical characteristics and decrease the rupture load of gels containing konjac glucomannan. The effects on the texture of gels containing konjac glucomannan and kappa-carrageenan (50 : 50) of various collagens with different molecular weights (porcine skin gelatin and collagen peptides from tilapia scales) and at different final concentrations were evaluated in terms of dynamic viscoelasticity, an extrusion test and a human mastication test using electromyography. The elastic modulus of the mixed gels decreased following the addition of collagen, regardless of the type. Gels containing 0.8% (w/w) gelatin melted at body temperature. Electromyography revealed that gels containing high-molecular weight collagen peptides (0.8%) exhibited significantly shorter mastication times and lower muscle activity, suggesting that these gels are easier to eat ; these gels were completely separated into two pieces in the extrusion test, whereas the other nine samples could only be partly masticated.

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We examined the use of stable carbon and nitrogen isotope ratios as a potential tool for verifying the geographical origin of Shirasuboshi. Products from 9 primary Shirasuboshi-producing areas in Japan and those imported from China and Korea were examined. The 9 primary production areas in Japan were classified into three groups by cluster analysis of stable carbon and nitrogen isotope ratios. Furthermore, Shirasuboshi imported from China was characterized by higher carbon and lower nitrogen isotope ratios than those from Japan and Korea. These results suggest that stable carbon and nitrogen isotope ratios are useful as tools for determining the geographical origin of Shirasuboshi.

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