Sensory importance and interactions of character impact compounds in brewed coffee model systems

The aim of the study was to investigate the sensory significance and interactions of the key odorants in brewed coffee model systems. The coffee model was obtained by mixing 43 odorants in a deodorized coffee base (0.5% coffee solids, pH = 5.0). The overall impression of the mixture was coffee-like. A sensory panel sorted the 43 odorants on the basis of odor similarity into as many groups as they felt necessary. From the cluster analysis of the odor sorting data, the 43 odorants were classified into 14 groups.; The impact of each group on the overall coffeeness of the aroma and on the intensity of the character of each of the 14 groups was screened using a fractional factorial design (Plackett-Burman design). Eight groups of odorants had a major impact on the aroma character of the model; five of each enhanced coffeeness. The remaining groups were not perceived in the model. However, the removal of all the six minor groups from the full model affected the sensory profile by increasing the earthy-moldy and raw potato-cheesy notes.; The impact of the eight major groups was investigated using two consecutive fractional factorial designs. In the first design, the impact of two major groups F (butter-caramel) and N (raw potato-cheesy) was investigated. F (butter-caramel) and N (raw potato-cheesy) masked the others groups of odorants when both groups were present at their high level. The 0.5 log concentration level change of the groups F (butter-caramel), N (raw potato-cheesy), CK (green-pea, medicinal), AELM (earthy-moldy, spicy, peanut, beef broth) in the 8-group model did not affect coffeeness of the aroma model. In the second design, the impact of each group A (earthy-moldy), E (spicy), L (peanut), C (green-pea), K (medicinal) on the 8-group model (F, M and N were kept at low concentration level) was investigated. The impact of these five groups was low in the studied range of concentration. There was no impact on coffeeness of the aroma model.; This study revealed that a limited number of odorants (25 out 43 odorants) present in the full aroma model give the coffee character of the model.