2006 Fiscal Year Final Research Report Summary
Effect of Microbial Treatment on the Degradation of Zinc-chelating Melanoidin in Coffee Brew
| Project/Area Number |
17500531
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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 |
Eating habits, studies on eating habits
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| Research Institution | Tokyo University of Agriculture |
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Principal Investigator |
HOMMA Seiichi Tokyo University of Agriculture, Department of Bioscience, Professor, 応用生物科学部, 教授 (50017240)
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| Co-Investigator(Kenkyū-buntansha) |
KIDA Satoshi Tokyo University of Agriculture, Department of Bioscience, Associate Professor, 応用生物科学部, 助教授 (80301547)
MIURA Daiki Tokyo University of Agriculture, Department of Bioscience, Assistant, 応用生物科学部, 助手 (10439896)
HOSODA Hiroshi Tokyo University of Agriculture, Department of Bioscience, Reserch Associate, 応用生物科学部, 有給副手 (40408662)
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| Project Period (FY) |
2005 – 2006
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| Keywords | coffee / melanoidin / zinc / chelate / microbial degradation / decolorization / Coriolus versicolo r IFO30340 / Paecilomyces Canadensis NC1 |
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| Research Abstract |
The roasting process is that is applied to green coffee beans forms the pleasant aroma, taste, and brown color of brewed coffee. The major reactions occurring during roasting are the Maillard reaction between sugars and amino groups, and the oxidative polymerization or degradation of phenolic compounds. Coffee melanoidin, the brown pigments in brewed coffee and in roasted coffee beans may have a partial structure similar to that in melanoidins and the polymers of phenolic compounds. Brewed coffee has metal-chelating activity which can result in trace element deficiency. It has been reported that an excessive intake of brewed coffee inhibits iron absorption. Coffee brews contain a brownish zinc-chelating polymer designated ApV. ApV was prepared from the precipitate formed in the coffee extracts by adding ZnC12 and purified using ion-exchange and cellulose column chromatographies. The dissociation constant Kd is an index of Zn(II) chelation in ApV to be dissociated into melanoidin moiety
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and zinc (II)
1. Effect of the roasting on the Zn(II) chelating activity in ApV was investigated.-Log Kd and the number of Zn(II)-binding sites were found to be 7〜8 and 1〜2 for light-roasting, 6〜7 and 3〜5 for medium-roasting, and 5 and 12 for dark-roasting, respectively. The roasting of coffee bean affects on the reduction in chelating activity of ApV fraction
2. We intended to develop to use mild conditions such as microbial incubation in depolymerization of macromolecular melanoidins. Two species of microbes were used: Paecilomyces canadensis NC1 was screened up in instant coffee exposed to ambient condition using decolorization of coffee melanoidin as an index, and Coriolus versicolo r IFO30340 was in the forest using model melanoidin prepared from reducing sugar and amino acid for decolorization substrate.
3. These two species of microbes were cultured in oxidative conditions with 3 kinds of model melanoidins prepared from reducing sugar and amino acid, 3 kinds of oxidized and colored polyphenolis, 3 kinds of caramels and browed foods such as miso, soy sauce, green coffee beans, instant coffee Less
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