Bitter and astringent characteristics of alkalized cocoa powder: Analysis using UPLC-Q-TOF-MS/MS and molecular...

Cocoa is a popular food, with a unique taste experience that significantly affects consumers' moods and health. Alkalization can change the taste properties of cocoa powder, but its taste perception mechanism is unclear. Ultraperformance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) analyzed phytochemical changes in cocoa powder before and after microwave-assisted alkalization. Dose-Over-Threshold (DOT) results showed that epicatechin, (-)-epigallocatechin gallate (EGCG), luteolin, protocatechuic acid, theobromine, and caffeine contributed significantly (DOT>1) to the bitterness of cocoa powder. Epicatechin, (-)-EGCG, syringic acid, protocatechuic acid, p-coumaric acid, caffeine, and 5-hydroxytryptamine played a key role in astringency. Molecular docking and molecular dynamics simulations revealed that these taste compounds bind effectively to bitter receptors (TAS2Rs) and salivary proteins (PRPs, α-amylase) to form a stable system. This study deepens understanding of cocoa powder's taste mechanism and offers a theoretical basis for taste regulation during processing.