When Machine Tastes Coffee

When Machine Tastes Coffee: Instrumental Approach To Predict the Sensory Profile of Espresso Coffee

Copyright © 2008 American Chemical Society

A robust and reproducible model was developed to predict the sensory profile of espresso coffee from instrumental headspace data. The model is derived from 11 different espresso coffees and validated using 8 additional espressos. The input of the model consists of (i) sensory profiles from a trained panel and (ii) on-line proton-transfer reaction mass spectrometry (PTR-MS) data. The experimental PTR-MS conditions were designed to simulate those for the sensory evaluation. Sixteen characteristic ion traces in the headspace were quantified by PTR-MS, requiring only 2 min of headspace measurement per espresso. The correlation is based on a knowledge-based standardization and normalization of both datasets that selectively extracts differences in the quality of samples, while reducing the impact of variations on the overall intensity of coffees. This work represents a significant progress in terms of correlation of sensory with instrumental results exemplified on coffee.

The perception elicited from drinking a freshly prepared espresso coffee represents a complex scientific phenomenon.1,2 This multisensory experience involves all our senses such as olfaction, taste, texture, trigeminal, and visual sensation. Furthermore emotions and cognitive processes constructed during drinking experiences, such as interactions between senses3 and product familiarity,4 modulate perception. Among the various sensory modalities, the aroma (smell) and taste, often referred to as flavor, are of paramount importance to the quality of coffee. The flavor compounds in a roast and ground (R&G) coffee depend on many factors, two of which are of particular importance. First, the green coffee variety and quality with its specific composition on precursors sets the stage for the later flavor development during roasting. Second, the roasting process which unlocks the flavor potential of the green coffee beans and creates the coffee flavor so much appreciated by coffee aficionados all over the world. Changes in these two factors affect most of the flavor compounds.

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