Unraveling the unique profile of Fu brick tea: Volatile components, analytical approaches and metabolic mechanisms of key odor-active compounds

Abstract

Background

Fu brick tea (FBT), a representative type of dark tea, develops distinctive flavor during fermentation. These flavor characteristics are essential for improving tea quality and market competitiveness. However, current understanding of FBT's flavor profile remains fragmented, with limited comprehensive analyses available. A thorough investigation into its flavor components and their variations is crucial for meeting consumer demands, driving industry advancement, and enhancing market competitiveness.

Scope and approach

This study provides the first comprehensive review of the flavor profile of FBT, consolidating various aspects, including an analysis of volatile compounds (VCs) that contribute to its distinctive aroma, methods for extracting and evaluating these compounds, the influence of odor-active compounds (OACs) on FBT's flavor, potential metabolic pathways of key odor-active compounds (KOACs), and the relevant microorganisms involved.

Key findings and conclusions

The distinctive flavor of FBT stems from a complex interplay of various VCs. Previous studies have reported over 1000 VCs in FBT, with hydrocarbons, ketones, and alcohols being the major contributors. The evaluation methods for FBT have shown that each extraction method has its unique advantages, and combining multiple methods has proven effective for analyzing OACs in FBT. By combining sensory evaluation with techniques such as GC-O/MS, AEDA, OAV, aroma recombination, and omission tests, the study effectively screens for KOACs and assesses their sensory impact on FBT's flavor profile. Notably, the majority of KOACs are formed during tea processing through enzymatic and non-enzymatic reactions, amino acid/hydrocarbon degradation and Maillard reactions. Although microbial activity is crucial for the unique characteristics of FBT, further research is needed to fully elucidate the specific metabolic pathways involved.