Development of a Sensory Evaluation Method for Polyphenols via Analysis of Chemical Structure and Organoleptic Properties: A Pilot Study

Polyphenols are plant metabolites with potent physiological activities. Despite their known bitterness and astringency, their specific sensory characteristics remain poorly understood. To clarify the relationship between polyphenol chemical structures and sensory profiles, we developed a sensory evaluation protocol for a young-adult panel. Following four days of intensive monthly training, the panel achieved proficiency in distinguishing bitterness, astringency, and acidity. Four polyphenols with distinct structures-gallic acid, quercetin hydrate, epigallocatechin gallate (EGCG), and a procyanidin-rich fraction (PRF)-were evaluated using flavor profile analysis (FPA) and 3-Alternative Forced Choice (3-AFC) tests for their qualitative properties, and quantitative descriptive analysis (QDA) for their quantitative properties. The results showed that gallic acid was acidic, and EGCG was bitter and astringent, with the intensity being concentration-dependent. In contrast, quercetin hydrate did not show any significant sensory properties. This methodology facilitates the elucidation of the relationship between polyphenol structures, and their organoleptic properties and subsequent findings help to further clarify the role of polyphenol-taste receptor interactions in health benefits.