Retronasal odor dependence on tastants in profiling studies of beverages

A trained sensory panel found consistent differences in retronasal odor intensities for several descriptors while profiling apple and orange beverages in which Brix (% sucrose) and acidity (% citric acid) were varied according to full factorial designs. Increasing Brix from 8 to 12 or decreasing acidity from 0.3 to 0.2 significantly increased scores for fruity, pear/candy, cooked, lactony, orange but significantly decreased scores for tin/metallic, acetaldehyde, green, apple cider, cucumber, grapefruit, lemon, rotten, terpenes. Some of these effects might be attributed to cognitive associations due to the panel’s extensive prior experience in profiling commercial samples. Correlations determined between the retronasal descriptor scores and scores for the gustatory descriptors sweet, sour in those data showed a large degree of internal consistency (i.e., positive for sweet, negative for sour and vice versa), but not always the same dependency as shown by the Brix and acidity effects (e.g., no significant correlations with green in the apple data). In two paired comparison surveys based on judgments of either sweetness or sourness, panelists’ a priori classification of 10 fruits was determined by several multivariate analyses. A bipolar sweet–sour scale for these fruits was shown by equivalence testing. A “green” mixture was added to beverages flavored to correspond to the extreme fruit types based on the survey, namely lemon (sour) and banana (sweet). Negative Brix effects (i.e., scores decreased as Brix increased) for green, as with the apple and orange flavors, were influenced neither by tastant associations with these fruits nor by their orthonasal odors. Lastly, there was no evidence for gustatory sweetness enhancement when the flavor had an orthonasal “sweet” odor, such as the banana flavor or the green apple flavor to which maltol + vanillin was added.