AUTHOR=Zhang Jian-yong , Cui Hong-chun , Feng Zhi-hui , Wang Wei-wei , Zhao Yun , Deng Yu-liang , Jiang He-yuan , Yin Jun-feng , Engelhardt Ulrich H. TITLE=Bitterness quantification and simulated taste mechanism of theasinensin A from tea JOURNAL=Frontiers in Nutrition VOLUME=10 YEAR=2023 URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1138023 DOI=10.3389/fnut.2023.1138023 ISSN=2296-861X ABSTRACT=

Theasinensin A is an important quality chemical component in tea, but its taste characteristics and the related mechanism are still unclear. The bitterness quantification and simulated taste mechanism of theasinensin A were researched. The results showed that theasinensin A was significantly correlated with the bitterness of tea. The bitterness threshold of theasinensin A was identified as 65 μmol/L for the first time. The dose-over-threshold (DOT) value of theasinensin A was significantly higher than that of caffeine in black tea soup. The concentration-bitterness curve and time-intensity curve of theasinensin A were constructed. The bitterness contribution of theasinensin A in black tea was higher than in oolong and green tea. Theasinensin A had the highest affinity with bitterness receptor protein TAS2R16, which was compared to TAS2R13 and TAS2R14. Theasinensin A was mainly bound to a half-open cavity at the N-terminal of TAS2R13, TAS2R14, and TAS2R16. The different binding capacity, hydrogen bond, and hydrophobic accumulation effect of theasinensin A and bitterness receptor proteins might be the reason why theasinensin A presented different bitterness senses in human oral cavity.