Bitterness and pungency perceived in extra virgin olive oil and in other foods: is there any relation?

The aim of this study was to investigate the bitterness and the pungency as positive attributes of extra virgin olive oils (EVOOs) by correlating their intensities with the same attributes perceived in aqueous solution and in other foods: chocolate cream (for bitterness) and tomato sauce (for pungency). For this purpose, the bitterness and the pungency of one EVOO, characterized by medium intensities of both attributes (IOC Panel test), were assessed by a group of male and female consumers (20-60 years old) using general Labeled Magnitude Scales (gLMS). The same subjects were also asked to evaluate the bitterness of four chocolate creams - at different concentrations of sugar - and the pungency of four tomato sauces - at different concentrations of capsaicin. The consumers assessed, by the gLMS, also three aqueous solutions: one of caffeine, one of capsaicin and a single solution of PROP (n-propyilthiouracyl). Based on the PROP perceived intensity, subjects were classified in three different classes, namely PROP super tasters, medium tasters, and nontasters. The density of fungiform papillae (FP) of each taster was also determined and the subjects were accordingly divided in high FP and low FP individuals. The statistical elaboration of all the results (Pearson’s correlations) permitted to establish that some relations exist among the bitterness and pungency perceived respectively in EVOO, in aqueous solutions and in other foods and to hypothesize possible relations with the classification of subjects, in respect with their PROP status and FP density. Moreover, all the significant differences among the average sensory results, calculated for each of the three PROP groups (by Fisher’s LSD or Kruskal-Wallis test) and for each of the two FP categories (by Student t-test or Mann Whitney test), were discussed: the objective was to highlight any eventual effects of FP number and/or PROP status on the perceived bitterness and pungency, within the different PROP and FP groups. This investigation represents a first approach for verifying also if the above mentioned sensory attributes, namely the perceptions linked with the molecules involved (polyphenols, capsaicin, caffeine, n-propyilthiouracyl), are somehow affected by the lipidic or aqueous nature of the foods.