2000 Fiscal Year Final Research Report Summary
Study on the New Enzymatic System For the Formation of Citral as the Biologically Active Substance
| Project/Area Number |
11680128
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
食生活
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| Research Institution | Ochanomizu University |
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Principal Investigator |
KUBOTA Kikue Ochanomizu University, School of Human Life and Environmental Science, Professor, 生活科学部, 教授 (90008730)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Ginger / Alcohol Dehydrogenase / Glycosidase / Geraniol / Geranial / Gitral / Flavor / NADP |
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| Research Abstract |
In Japan both of fresh immature and mature rhizomes of ginger are used for various dishes. But the main flavor compounds are different between immature ginger and mature one. The former contains geraiol and geranyl acetate mainly, in contrast the concentration of citral (geranial and neral), especially geranial are increased dramatically in the mature ginger. In this study, it was found for the first time that the rhizomes of ginger have glucosidase activity which has the specificity for glucoside and galactoside. In addition, alcohol dehydrogenase (ADH) activity was also comfirmed for the first time. And the ADH of ginger was dependent of NADP and the optimum pH is 9.0. It also showed the specificity for geraniol. We also investigated the relationship between the quantitiy of geranial formed and the ADH activity during growth and storage of ginger to clarify the mechanism for the increase in content og geranial in maturing and stored ginger. The amounts of geranial reached the maximum after 30 days of storage, and after that slightly decreased or remained constant. The change of the enzyme activities above was parallel well to the geranial formation. From these results, it was concluded that ADH activity of ginger would influence the formation of geranial in ginger. the purification and characterization of ADH should be accomplished to use the rhizomes of ginger more effectively.
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