Taste perception study to help advance functional food designs

A pilot study conducted by researchers at Shibaura Institute of Technology has developed a new sensory evaluation method that links the chemical structures of polyphenols with their distinct taste properties. Using trained human panellists, researchers showed that different polyphenols produce unique sensory effects, including bitterness, acidity and astringency. The findings may help improve functional food design and food processing technologies while advancing understanding of how taste-related sensory pathways could contribute to digestion, metabolism and health-related responses.

Reason for the research

Polyphenols are naturally occurring plant compounds widely found in tea, cocoa, fruits, vegetables and other foods. They are well known for their potential health benefits, including reducing the risk of cardiovascular disease, diabetes and age-related disorders. However, despite decades of research on their physiological effects, scientists still understand relatively little about how the specific chemical structures of polyphenols influence their taste sensations, such as bitterness and astringency. These sensory properties strongly affect food preferences and may also influence biological responses in the digestive system.

To address this challenge, a research team led by Professor Naomi Osakabe from the Department of Functional Control Systems, Graduate School of Engineering and Science, Shibaura Institute of Technology, Japan, along with Hitomi Nakamura and Moeka Ogata from the same institute, developed a structured sensory evaluation system using trained human panellists to quantitatively analyse the taste characteristics of polyphenols and connect them with their chemical structures. Their findings were published in Volume 15, Issue 8 of the journal Foods on 17 April 2026.

The study focused on four representative polyphenols with different chemical structures: gallic acid, quercetin hydrate, epigallocatechin gallate (EGCG) and a procyanidin-rich fraction derived from cocoa. Before testing, seven carefully selected panellists underwent four months of intensive sensory training designed to improve their ability to distinguish acidity, bitterness and astringency. The researchers combined multiple sensory evaluation approaches, including flavour profile analysis, quantitative descriptive analysis, and three-alternative forced-choice testing, to ensure good results.

The experiments revealed clear sensory differences between the compounds. Gallic acid produced strong acidity similar to citric acid, while EGCG, a major compound in green tea, generated pronounced bitterness and mild astringency. The procyanidin-rich fraction showed intense astringency, likely due to its polymerised structure interacting with salivary proteins. In contrast, quercetin hydrate displayed little detectable taste, mainly because of its low water solubility.

“While polyphenols are known to produce bitter and astringent sensations, very few studies have objectively evaluated these properties using trained human panels. We wanted to establish a reliable system that could scientifically connect sensory perception with chemical structure.” Osakabe said.

Benefit for the food industry

The researchers believe these findings could significantly benefit the food industry, particularly in the development of functional foods and beverages. By understanding how molecular structures influence taste, manufacturers may be able to improve food palatability while preserving beneficial health properties. The study may also contribute to designing products with targeted sensory effects that encourage healthier dietary habits.

Another important aspect of the research involves the growing recognition that taste receptors are not limited to the mouth. Recent studies suggest that bitter and astringent compounds can interact with receptors in the digestive system, influencing hormone release, glucose regulation and gastrointestinal function. Understanding the sensory characteristics of polyphenols may therefore help explain some of their health-promoting effects.

“Our long-term goal is to create predictive models that can estimate sensory properties directly from chemical structures. This could support the future development of next-generation functional foods tailored for both taste and health benefits,” Osakabe said.

Overall, the study provides one of the first systematic frameworks for quantitatively evaluating polyphenol taste characteristics using trained human panels. By linking molecular structure with sensory perception, the research opens new opportunities for food science, nutrition research and functional food innovation while improving understanding of how taste-related pathways contribute to human health.

Image credit: iStock.com/Antonio_Diaz