Sensory impact of free fatty acids on the aroma of a model Cheddar cheese

The fatty acid profile from the retronasal aroma of Cheddar cheese was determined using the retronasal aroma simulator (RAS). Seven odor potent fatty acids identified in Cheddar cheese were placed in model systems and sampled in the RAS. Volatile acids were trapped by solid phase microextraction and identified by GC/MS. The six released fatty acids were added to a model cheese system and subjected to a descriptive analysis sensory test, using omission testing (N-1). Six cheese models, each omitting one fatty acid, were tested in triplicate against a complete model by a trained panel, under a randomized complete block design. Panelists rated the intensity of six descriptors. In one additional test session, the complete model was tested against a model omitting all fatty acids. Results indicated that the omission of propionic acid from the cheese model led to a significant increase (alpha = 0.10) in the ratings for the 'cream' descriptor (P = 0.08). The omission of all fatty acids resulted in a significant decrease in the ratings for the 'sweaty' descriptor (P = 0.07). Surprisingly, the ratings for the 'Cheddar' descriptor did not change under any circumstances. This suggests that although some compounds contribute heavily to the aroma of a food based on their odor potency, the removal of such compounds does not necessarily alter the sensory perception of the overall food concept. (C) 2002 Published by Elsevier Science Ltd.