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2002 Fiscal Year Final Research Report Summary

Specific sterilization of psychrotrophs in foods by inactivation of alanine racemase

Research Project

Project/Area Number 12480026
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 食生活
Research InstitutionNara Women's University

Principal Investigator

YOKOIGAWA Kumio  Nata Women's University, Fuculty of Human Life and Environments, Associate Professor, 生活環境学部, 助教授 (60230637)

Project Period (FY) 2000 – 2002
Keywordspsychrotroph / alanine racemase / food hygiene / 有機酸 / 香辛料
Research Abstract

Psychrotrophic bacteria are widely distributed in nature, and often cause deterioration in foods stored at a low temperature. Accordingly, the bacteria have been studied to better understand food preservation, While psychrotrophs are easily sterilized by heat treatment, their extracellular hydrolytic enzymes survive and degrade the quality of foods. Therefore, sterilizing psychrotrophs before their growth in foods is important for food preservation at low temperature. However, there is no effective sterilization method of psychrotrophs in foods other than thermal sterilization, which often changes the original taste.
Alanine racemase (EC 5.1.1.1) is a pyridoxal 5'-phosphate-dependent enzyme catalyzing racemization of L- and D-alanine. The enzyme occurs widely in bacteria and is essential in synthesis of peptidoglycan of bacterial cell walls by providing the D-enantiomer. The peptidoglycan biosynthesis is unique to bacteria, and therefore the enzyme has been a target of antibacterial dru … More gs. We examined the sensitivity of psychrotrophs to organic acids and spices in comparison with mesophiles, in order to develop an effective sterilization method of psychrotrophs based upon inactivation of alanine racemase.
Fsychrotrophs such as P.fluorescens and B.psychrosaccharolyticus were found to be more sensitive to citrate, acetate, lactate, and succinate at 0.01% concentration than the mesophiles. The organic acid at the concentration also inactivated alanine racemase. Mesophiles were tolerant to the treatment and the intracellular alanine racemase in mesophiles was not inactivated.
Also, psychrotrophs were more sensitive to various spices than the mesophiles, although the sensitivity of psychrotrophs to each spice was different depending on the species. When an equal volume of allspice, turmeric, nutmeg, and laurel leaves extracts was mixed and analyzed, the mixed extract completely suppressed the growth of all surveyed psychrotrophs at the concentration of 0.016% for 6 days. When eggplant, cucumber, and cabbage were soaked in the 0.016% mixed extract at 25oC for 10 min and stored at 4oC for 11 days, the growth of psychrotrophs was completely suppressed. The mixed spice extract may be useful for the suppression of psychrotrophs. Less

  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] Yoko Okubo: "High Catalytic Activity of Alanine Recemase from Psychrophilic Bacillus psychrosaccharolyticus at High Temperature in the Presence of Pyridoxal 5'-phosphate"FEMS Microbiol.Lett. 192. 169-173 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Kumio Yokoigawa: "Structure and function of Psychrophilic Alanine Racemase"J.Mol.Cat.B : Enzymatic. 12. 27-35 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Kumio Yokoigawa: "Gene Cloning and Charaacterization of Alanine Racemases from Shigella dysenteriae, Shigella boudii, Shigella flexneri, and Shigella sonnei"Biochem.Biophys.Res.Commun.. 288. 676-684 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yoko Okubo et al.: "High Catalytic Activity of Alanine Racemase from Psychrophilic Bacillus psychrosaccharolyticus at High Temperatures in the Presence of Pyridoxal 5'-phosphate"FEMS Microbiol.Lett.. 192. 169-173 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Kumio Yokoigawa, et al.: "Structure and function of Psychrophilic Alanine Racemase"J.Mol.Cat.B : Enzymatic. 12. 27-35 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Kumio Yokoigawa, et al.: "Gene Cloning and Characterization of Alanine Racemases from Shigella dysenteriae, Shigella boydii, Shigella fiexneri, and Shigella sonnei"Biochem.Biophys.Res.Common.. 288. 676-684 (2001)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2004-04-14  

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