| Abstract
| - In a roasted Arabica coffee brew, the potent roasty odor quality compound was identified as3-mercapto-3-methylbutyl acetate by comparison of its Kovats gas chromatography retention index,mass spectrum, and odor quality to those of the synthetic authentic compound. 3-Mercapto-3-methylbutyl acetate has been identified for the first time in the coffee, and according to the results ofthe aroma extract dilution analysis, the contribution of this compound to the flavor of the roastedcoffee brew varied depending on the degree of the coffee bean roasting. The concentration of thiscompound in the coffee brews as with 3-mercapto-3-methylbutyl formate increased with an increasein the degree of roasting. However, the slope of the amount of both esters was different, and3-mercapto-3-methylbutyl acetate hardly increased with a low degree of roasting at more than a 21luminosity (L)-value, but it rapidly increased when the roasting degree of the coffee beans reachedthe L-value of 18. These results suggested that the contribution of 3-mercapto-3-methylbutyl acetateto the overall flavor is peculiar to the flavor of the highly roasted coffee. Keywords: Coffee; 3-mercapto-3-methylbutyl acetate; roast degree; aroma extract dilution analysis
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