Molecular sensory basis of the unique “cocoa aroma” in white tea: An integrated study combining HS-SPME-GC–MS, GC-O, molecular docking, and addition tests

Cocoa aroma is a pleasant and highly market-accepted aroma type in white tea, yet its underlying key aroma components remain unclear. In this study, sensory quantitative descriptive analysis (QDA), gas chromatography–mass spectrometry (GC–MS), gas chromatography-olfactometry (GC-O), molecular docking , and aroma addition tests were employed to elucidate the aroma characteristics and aroma profile of cocoa aroma white tea (CCWT), traditional white tea (WT) and cocoa beans (CC), and then construct a comprehensive aroma flavor wheel. It was observed that CCWT consists of a composite aroma dominated by Cocoa aroma, accompanied by flowery, sweet, and herbal aroma. Ten compounds were identified as key aroma constituents in CCWT, including linalool , nerol , and β-ionone. Notably, isovaleraldehyde , 2-methylbutyraldehyde, and phenylacetaldehyde were identified as the primary aroma components contributing to the cocoa aroma. Molecular docking results revealed that 3 key aroma components generate cocoa aroma through hydrogen bonding and hydrophobic interactions with olfactory receptors , with binding energies of less than −4 kcal/mol. The addition tests indicated that isovaleraldehyde and 2-methylbutyraldehyde primarily contribute to the cocoa aroma in CCWT, while phenylacetaldehyde likely enhances this aroma through synergistic effects with other compounds. This research provides essential scientific support for enhancing white tea quality and guiding product development. A solid foundation has been established to facilitate sustainable growth of the broader tea industry.