# Biomimetic Fermentation Reshapes Precursor Pools to Drive Synergistic Roasting Reactions and Enhance Coffee Flavor Complexity

## TL;DR

This study shows how biomimetic fermentation can enhance coffee flavor by reshaping chemical precursors and improving roasting reactions.

## Contribution

The study introduces a biomimetic fermentation method that quantitatively optimizes coffee flavor through precise precursor modulation and roasting chemistry.

## Key findings

- Biomimetic fermentation increases free amino acids like leucine and phenylalanine by 1.89-fold.
- BF enhances esterification flux 3.08-fold, boosting fruity aroma compounds like ethyl acetate.
- BF improves thermal stability of bioactive compounds such as 5-caffeoylquinic acid and trigonelline.

## Abstract

Deciphering the coupling mechanisms between post-harvest precursor shaping and roasting thermochemistry is pivotal for precise coffee flavor modulation. This study aimed to investigate the regulation mechanisms of in vitro biomimetic fermentation (BF) on the precursor-roasting reaction network. Integrated multi-omics characterization and sensory evaluation reveal that the BF protocol achieves targeted substrate enrichment, notably amplifying free amino acids—particularly leucine and phenylalanine—by 1.89-fold while accumulating lactate and succinate buffering salt systems. This reconfiguration constructs a matrix with superior thermal buffering capacity (ΔpH 0.17), which optimizes the thermal reaction kinetic window during roasting. Consequently, BF drives a 3.08-fold surge in esterification flux, significantly increasing the abundance of key fruity markers such as ethyl acetate and ethyl isovalerate. It also enhances the diversity of Maillard products, specifically elevating nutty-associated alkylpyrazines (e.g., 2,3,5-trimethylpyrazine). Concurrently, BF improves the thermal stability of bioactive compounds, including 5-caffeoylquinic acid (5-CQA) and trigonelline. Multi-scale molecular dynamics and quantum chemical calculations elucidate that BF-derived organic acid–salt complexes exert a ‘pseudo-catalytic effect,’ lowering activation free energy barriers for critical aroma-generating reactions by approximately 8.5 kcal/mol. This study demonstrates high sensory predictability (predictive model R2 = 0.98) and provides a quantitative theoretical framework to advance coffee processing from empirical observation to rational flavor design.