Objective measurement of pungency, bitterness, and astringency in food

Background: In the food sector, sensory evaluation is crucial for food and new food products. Objective measurement of sensory characteristics is a tool used to assess food preference using instruments.  Methods: The sources of information were the following scientific databases: Scopus, ScienceDirect, PubMed, ResearchGate, the FFHDJ/FFC journal ecosystem and Google Scholar. The parameters of the publications were as follows: publications from 1978 until 2025 (61 references were selected for this review). Results: In the present study, the differences between subjective and objective tests were presented. The basic tastes perceived subjectively by the tongue –sweetness, sourness, saltiness, and bitterness– were reviewed, along with metallic and umami tastes. Umami, the fifth taste, was described as contributing to the characteristic flavor of umami-rich foods. Tastes, their reference substances, and concentrations were summarized. Mouthfeels such as pungency and astringency were reviewed in depth. Furthermore, the characterization of pungency and the associated Scoville Heat Units (SHU), including pungency levels of capsaicinoids, as well as the pungency of ginger and cinnamon, and the pungency of onion and garlic, were explained. The sources of bitterness, bitterness measurement using the International Bitterness Units scale (IBU), bitterness determination, debittering techniques, and food bitterness and pungency regulations were described. Astringency causes, factors affecting, astringency measurement using different objective techniques and quantifying astringency using the gelatin index, and de-astringency of food to increase edibility were also considered. Novelty: This review highlights the importance of using objective measurement tools to determine tastes and mouthfeels of new foods or food products during development and processing. Integrating the health implications of taste/mouthfeel compounds with strategies to debitter and de-astringe nutritional and nutraceutical components to improve edibility provides a distinctive contribution. Conclusion: This review can be helpful for consumers, food manufacturers, and catering and food service industries in understanding, choosing, and dealing with key sensory attributes (i.e., basic tastes, pungency, bitterness, and astringency) of foods, spices, and spicy food and other related substances for their sensory preferences. Keywords: sensory evaluation, subjective tests, basic tastes, mouthfeel, Scoville, functional foods