Changes in Major Aromatic Compounds of Roasted Coffee Bean Powder During Storage Using Colorimetric Sensor Array

Aroma is one of the most important factors in the quality of coffee. A colorimetric sensor array (CSA) that gives a pattern of responses to the coffee aroma was used to follow changes during storage. The response of the array to four major aroma compounds of coffee, furfuryl alcohol, dimethyl trisulfide, 2,3-butanedione and 2,3-pentanedione, was examined first, and the four compounds proved distinguishable by their response patterns in hierarchical cluster analysis (HCA). The changes in volatile constituents of coffee during storage at 4 and 25 °C were studied. The response patterns of the stored samples were examined by principal component analysis (PCA). The samples became less distinguishable from one another as the storage period lengthened, converging in the score plots from day 10 at 4 °C and from day 5 at 25 °C. This behavior is consistent with a loss of aroma freshness during storage. GC-MS was used to quantify individual aroma compounds in the stored samples. These results show that the colorimetric sensor array has potential as a rapid indication of the overall state of coffee aroma during storage, complementing the quantitative analysis of individual compounds by GC-MS.