Detection of Spicy Compounds Using the Electronic Tongue

Abstract

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.

Electronic Tongue and Consumer Sensory Evaluation of Spicy Paneer Cheese

“…The spicy sensor is not the only sensor used to discriminate among the samples. Previous research using the e‐tongue for evaluation of spicy compounds had similar findings in that the spicy sensor did not correspond to the sample with the highest concentration of capsaicin (Paup et al., ). The study theorized that at lower concentrations of capsaicin in the sample the e‐tongue may need to use all of the sensors to help discriminate because differences at the lower concentrations may be less apparent and more difficult to detect (Paup et al., ).…”

“…Previous research using the e-tongue for evaluation of spicy compounds had similar findings in that the spicy sensor did not correspond to the sample with the highest concentration of capsaicin (Paup et al, 2018). The study theorized that at lower concentrations of capsaicin in the sample the e-tongue may need to use all of the sensors to help discriminate because differences at the lower concentrations may be less apparent and more difficult to detect (Paup et al, 2018). Nevertheless, the data show that at concentrations at which consumers have a difficult time discriminating between in sensory evaluations, the e-tongue can be a useful qualitative measure of discrimination among spicy food samples.…”

“…The e-tongue has a sensor array capable of detecting nonvolatile compounds in liquid matrices to simulate human taste, detecting sweet, salty, bitter, sour, umami, metallic, and spicy (Diako, Vixie, Weller, Dycus, & Ross, 2017;Lipkowitz, Ross, Diako, & Smith, 2018). Recent research explored the ability of the e-tongue to characterize spiciness of various spicy compounds, such as capsaicin, eugenol, menthol, p-cymene, piperine, thymol, and zingerone, accompanying this detection with consumer evaluation (Paup, Barnett, Diako, & Ross, 2018). The e-tongue discriminated among the seven spicy compounds, one of which was capsaicin, and among three concentrations of a single spicy compound.…”

“…The e‐tongue discriminated among the seven spicy compounds, one of which was capsaicin, and among three concentrations of a single spicy compound. E‐tongue results were compared to results from a sensory panel to conclude the e‐tongue is a convenient method that can work well in conjunction with consumer panel results to evaluate spicy compounds in water (Paup et al., ).…”

Relationship between mustard pungency and allyl‐isothiocyanate content: A comparison of sensory and chemical evaluations

“…The sensory characteristics of food products are commonly assessed via sensory methods by untrained or specifically trained consumer or expert panels. Nevertheless, the evaluation of pungent products poses several challenges, as the assessment of products with intense sensory characteristics leads to the fatigue of the panelists (Paup, Barnett, Diako, & Ross, 2019; Rousseau, Rogeaux, & O'Mahony, 1999). Therefore, only a few products can be evaluated in each session and the inter‐stimulus interval needs to be chosen depending on the chemical stimulus inducing the sensation in order to avoid desensitization (Brand, 2006; Brand & Jacquot, 2002).…”