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Iida, Japan

Ishiguro T.,Asahimatsu Foods Co. | Ono T.,Iwate University
ACS Symposium Series

The variation factor in soybean phytate content and its influence on tofu texture was investigated. Twenty-seven soybean varieties were grown in a drained paddy field and upland field, and then their protein and phytate contents were determined using the FT-IR method. 12 soybean varieties grown in the drained paddy field contained significantly more phytate than those in the upland field. Variation in the phytate contents due to the different varieties was also observed. Therefore phytate content was affected by both environmental and hereditary factors. The increase of phytate concentration in soymilk shifted optimal coagulant concentration in both Mg and GDL tofu. The data showed the variation of phytate content influenced on tofu texture. © 2010 American Chemical Society. Source

Onose S.,Tohoku University | Ikeda R.,Asahimatsu Foods Co. | Nakagawa K.,Tohoku University | Kimura T.,Japan National Agricultural Research Center | And 3 more authors.
Food Chemistry

1-Deoxynojirimycin (DNJ), a potent α-glycosidase inhibitor, has therapeutic applications in treatments of HIV, Gaucher's disease, and diabetes. DNJ has been extracted from natural sources (mulberry leaves) for therapeutic purposes; however, DNJ ingredients are in limited supply and are costly to obtain on a large scale. Since certain strains of Bacillus and Streptomyces species reportedly produce DNJ, they may serve as potential sources for high-yield DNJ production. In this study, we obtained evidence for a DNJ production in Bacillus subtilis DSM704 by hydrophilic interaction chromatography-tandem mass spectrometry. In addition, from a screen of 750 microorganisms, we identified additional Bacillus strains (Bacillus amyloliquefaciens AS385 and Bacillus subtilis B4) that produce DNJ in large quantities. Investigation of the effect of various culture conditions, using Bacillus subtilis DSM704 and the DNJ high-production Bacillus strains, provided evidence for the importance of sorbitol supplementation on the yield of the DNJ precursor, 2-amino-2-deoxy-D-mannitol, thereby increasing DNJ production. The role of sorbitol in increased DNJ production was supported by an observed increase in mRNA expression of the biosynthetic gene, gabT1. When Bacillus amyloliquefaciens AS385 was cultured in medium supplemented with sorbitol, extracellular DNJ concentration reached a maximum of 460 mg/l of medium (equivalent to 9.20 mg/g of freeze-dried medium), indicating that this strain can serve as a source for food- and drug-grade products. These findings not only lead to a further understanding of the DNJ biosynthetic pathway, but also suggest a method for microbial mass production of DNJ for therapeutic applications. © 2012 Elsevier Ltd. All rights reserved. Source

Ishiguro T.,Asahimatsu Foods Co. | Tatsunokuchi S.,Asahimatsu Foods Co. | Mitsui N.,Asahimatsu Foods Co. | Kayahara H.,Asahimatsu Foods Co. | And 3 more authors.
Bioscience, Biotechnology and Biochemistry

The serum total cholesterol concentration was significantly lower in the kori-tofu feeding group than in the soy protein isolate (SPI) group, except on the 28th day of the experiment. The high-molecular-weight fraction (HMF) content of the kori-tofu protein was significantly higher than that of SPI. This difference in the HMF content may have influenced the cholesterollowering effect of the protein. Source

Mitsui N.,Shinshu University | Mitsui N.,Asahimatsu Foods Co. | Murasawa H.,Asahimatsu Foods Co. | Sekiguchi J.,Shinshu University
Journal of General and Applied Microbiology

Poly-γ-glutamic acid (γPGA), a polymer of glutamic acid, is a component of the viscosity substance of natto, a traditional Japanese food made from soybeans fermented with Bacillus subtilis (natto). Here we investigate the effects of the cell wall lytic enzymes belonging to the D,L-endopeptidases (LytE, LytF, CwlO and CwlS) on γPGA production by B. subtilis (natto). γPGA levels in a cwlO disruptant were about twofold higher than that of the wild-type strain, whereas disruption of the lytE, lytF and cwlS genes had little effect on γPGA production. The molecular size of γPGA in the cwlO disruptant was larger than that of the wild-type strain. A complementary strain was constructed by insertion of the entire cwlO gene into the amyE locus of the CwlO mutant genome, and γPGA production was restored to wild-type levels in this complementary strain. These results indicated that the peptidoglycan degradation enzyme, CwlO, plays an important role in γPGA production and affects the molecular size of γPGA. Source

Mitsui N.,Shinshu University | Mitsui N.,Asahimatsu Foods Co. | Murasawa H.,Asahimatsu Foods Co. | Sekiguchi J.,Shinshu University
Nippon Shokuhin Kagaku Kogaku Kaishi

The effects of spore formation on natto qualities were investigated using the spo0A, sigH, sigE, sigF, sigK and sigG mutants of Bacillus subtilis (natto). None of mutants formed heat-resistant spores. The glutamic acid contents of the natto produced by spo0A and sigH mutants were less than that of the wild-type strain. The glutamic acid and the ammonia contents of the natto produced by the sigJi, sigF, sigK and sigG mutants tended to increase, but the organoleptic tests showed that the natto produced by them were the same as for the natto produced by the wild-type strain. The natto produced by these mutants did not contain the heat-resistant spores. Therefore, these natto may have a potential to be used in the processed food industry that wants to avoid contamination due to spores. (Received Jun. 1, 2010 ; Accepted Jul. 7, 2010). Source

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