Evaluation of Coffee Aroma by Principal Component Analysis

(Studies on Aroma of Coffee Part VII)

Abstract

Objective evaluation of coffee aroma was performed by the combination of gas chromatographic analysis and principal component analysis. (1) Arabica and robusta coffees were clearly separated by the first and second principal components and the principal components of each trade variety of coffee could be correlated with the sensory evaluation by a professional expert (cup tester) regarding to arabica coffees. (2) The blended coffees with the blending ratio of 1:1 (robusta/arabica coffee) were affected more strongly by robusta than arabica coffee. The blended coffees with the ratio of 3:1 was closely similar to robusta coffee but the coffees with the ratio of 1:3 had a quite different ftavor quality from the original coffees. (3) The good relation between a roasting degree and principal components was observed from Light to French roasted beans. Consequently, the effect of roasting on flavor formation was different between arabica and robusta coffee.