Flavoring Components of Raw Monsooned Arabica Coffee and Their Changes during Radiation Processing
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- 作者：Prasad S. Variyar ; Rasheed Ahmad ; Rajeev Bhat ; Zareena Niyas ; and Arun Sharma
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2003
- 出版时间：December 31, 2003
- 年：2003
- 卷：51
- 期：27
- 页码：7945 - 7950
- 全文大小：80K
- 年卷期：v.51,no.27(December 31, 2003)
- ISSN：1520-5118
文摘
Volatile aroma principles, nonvolatile taste constituents (caffeine and chlorogenic and caffeic acids),and glycosidically bound aroma compounds of monsooned and nonmonsooned raw arabica coffeewere analyzed using gas chromatography-mass spectrometry (GC-MS) and high-performance liquidchromatography (HPLC). Among the most potent odor active constituents known to contribute to thearoma of the green beans, 3-isopropyl-2-methoxypyrazine, 3-isobutyl-2-methoxypyrazine, 4-vinylguaiacol, 
mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-damascenone, (E)-2-nonenal, trans,trans-2,4-decadienal, phenylacetaldehyde, and 3-methylbutyric acid were detected by GC-MS in both samples. A decrease in content of methoxypyrazinesand an increase in 4-vinylguaiacol and isoeugenol resulted in a dominant spicy note of monsoonedcoffee. These phenolic compounds exist partly as their glycosides, and their release from the boundprecursors during monsooning accounted for their higher content in monsooned coffee. A considerabledecrease in astringent chlorogenic acid as a consequence of hydrolysis to bitter caffeic acid wasnoted in monsooned coffee. Radiation processing of nonmonsooned beans at a dose of 5 kGy resultedin an increased rate of monsooning. At this dose a quantitative increase in most of the aroma activecomponents could be observed in all samples studied. Hydrolysis of chlorogenic acid to caffeic acidwas noted in radiation-processed monsooned coffee beans irrespective of whether the treatmentwas carried out before or after monsooning. These changes were, however, not observed in irradiated,nonmonsooned coffee beans, suggesting an enzymatic rather than a radiolytic cleavage of chlorogenicacid. A rationale behind the mechanism of monsooning and radiation-induced enhancement of themonsooning process is discussed.Keywords: Monsooned coffee; mages/gifchars/gamma.gif" BORDER=0 >-radiation; raw coffee beans; volatiles; caffeine; chlorogenic acid