Detection of Spicy Compounds Using the Electronic Tongue.

The consumption of spicy food products has increased, resulting in an increased demand for these products. The sensory evaluation of foods containing spicy compounds provides challenges due to their trigeminal innervation and associated sensory fatigue. Thus, for the routine evaluation of spices, a need exists for rapid and objective methods of analysis; the electronic tongue (e-tongue) provides a potential solution. The objective of this study was to evaluate the ability of the e-tongue to distinguish among spicy compounds at varying concentrations. Due to the diversity of spicy compounds, seven spicy compounds were selected: capsaicin, thymol, piperine, zingerone, p-cymene, menthol, and eugenol. For each of these compounds, a low concentration (1.427 × 10^-5 to 0.85 mg/L), medium concentration (2.854 × 10^-5 to 1.49 mg/L), and high concentration (0.0133 to 30.5 mg/L) were analyzed by the e-tongue. For each compound, the e-tongue discriminated among the concentrations with discrimination indices between 72% to 84%. Based on the responses of the e-tongue sensors, the samples formed three clusters. Cluster 1 contained menthol, eugenol, and p-cymene, cluster 2 contained capsaicin and thymol, and cluster 3 contained piperine and zingerone. Same-different sensory testing was completed on a representative sample from each cluster. Untrained consumers (n = 80) distinguished among the three clusters, verifying the clusters identified by the e-tongue. These results demonstrated that the e-tongue could be applicable in product development and the routine evaluation of spicy products. PRACTICAL APPLICATION: As the e-tongue differentiated among spicy compounds in an effective manner, it could be used instead of or alongside sensory evaluation when evaluating spicy compounds to reduce sensory fatigue associated with routine testing. Utilizing the e-tongue for spicy products will be an important area of research as the market for such products continues to grow.