Electronic Tongue and Consumer Sensory Evaluation of Spicy Paneer Cheese

Evaluating sensory properties of spicy foods can be challenging due to how quickly individuals experience fatigue. Analytical methods, such as HPLC quantification of capsaicin, are accurate. However, they may not always be interchangeable with perception of spiciness by consumers. The electronic tongue (e-tongue) offers a unique opportunity to simulate human perception of capsaicin pungency with an analytical method. This study evaluated consumer's and the e-tongue ability to discriminate among paneer cheese samples containing different levels of capsaicin (1.875, 3.75, 7.5, 15, and 30 ppm). Over 2 days, using a blocked design to minimize fatigue, consumers (n = 110) evaluated samples using a difference from control sensory test. Consumers distinguished the spicy paneer sample from the control (0 ppm) at 3.75, 7.5, 15, and 30 ppm (P < 0.05). Differences were found among sample 3.75, 7.5, and 15 ppm (P < 0.05). However, no significant differences were found between control and 1.875 ppm or between samples 15 and 30 ppm. Although these high and low concentrations were challenging for consumers, the e-tongue resulted in a high degree of discrimination of 93% among all samples. On the principal component analysis plot created by the e-tongue, PC1 explained 85.6% of the variability and was associated with spicy, sweet, salty, sour, and umami sensors. PC2 explained 7.96% and was associated with the bitter and metallic sensors. The 3.75 and 15 ppm samples were defined by PC1, while PC2 defined samples 1.875 and 30 ppm. These results conclude that the e-tongue may be useful in qualitative discrimination among spicy paneer along with sensory evaluation. PRACTICAL APPLICATION: As the market for spicy foods continues to grow, methods for rapid, accurate analysis of the sensory qualities of the food products is needed. As the electronic tongue discriminated effectively among spicy paneer cheese samples, the method could be used alongside sensory testing to evaluate spicy food samples without encountering the typical issues of fatigue common with evaluating spicy foods.