Goat cheese flavor:: Sensory evaluation of branched-chain fatty acids and small peptides

Small peptides (MW < 1000 g/mol) and volatile fatty acids of goat cheese were studied for their favorite properties. The threshold values of 4-methyl- and 4-ethyl-octanoic acids-responsible for the typical goat note were evaluated at pH 5 for orthonasal aroma in a citrate buffer and for retronasal aroma after incorporation in a cheese model. Though the concentration of the 4-ethyl- was lower than the concentration of the 4-methyl-octanoic acid in goat cheese, its relative impact on the typical goat flavor appeared more important because of its much lower threshold value. The small peptides, isolated by nanofiltration of the ultrafiltered water-soluble extract at pH 3, were incorporated in the cheese model. Sensory evaluations with omission tests did not allow us to find any taste activity for this peptidic fraction.