# Fortified Espresso Coffee With Essential Oils: Compositional Analysis, Matrix Stability, and Antimicrobial Performance

## TL;DR

This study shows that adding essential oils to espresso coffee improves its antimicrobial properties without changing its basic taste or quality.

## Contribution

The study introduces a new functional beverage by incorporating essential oils into espresso coffee and evaluates its stability and antimicrobial effects.

## Key findings

- Adding essential oils did not significantly alter the pH of the espresso coffee.
- Cymbopogon citratus showed the strongest antimicrobial effect against Staphylococcus aureus.
- UHPLC profiles confirmed the stability of key compounds like chlorogenic acid and caffeine.

## Abstract

This study was aimed at evaluating the physicochemical stability and antimicrobial potential of essential oils (EOs) from Cymbopogon citratus (lemon verbena), Citrus reticulata (mandarin), and Peperomia inaequalifolia (congona) incorporated into an espresso coffee drink. The EOs were obtained by hydrodistillation and characterized by GC‐MS, FTIR, and DSC. The coffee beverage was formulated with different concentrations of EO (0.10, 0.15, and 0.20% v/v), and physicochemical parameters (pH, titratable acidity, and soluble solids), total phenols (Folin–Ciocalteu), antioxidant capacity (DPPH), and specific metabolites (UHPLC) were analyzed. Antimicrobial activity against Staphylococcus aureus ATCC 25923 was also evaluated by microdilution and disk diffusion. The results showed that adding EOs did not significantly alter the beverage′s pH (4.74–4.83). However, they increased acidity, with C. citratus at 0.20% (8.83 meq/100 mL) and soluble solids, with a maximum in P. inaequalifolia at 0.15% (6.17°Brix). The total phenolic content increased in all formulations, with P. inaequalifolia at 0.20% (818.11 mg GAE/100 mL) standing out, while the antioxidant capacity varied compared to the control. The UHPLC profiles showed stability of the major compounds (chlorogenic acid, caffeine, and caffeic acid). In terms of antimicrobial activity, C. citratus had the greatest inhibitory effect, with halos of up to 5.4 mm in a coffee beverage whose EO had an MIC of 2.5% v/v and an MBC of 5% v/v. Overall, the results show that incorporating EOs into espresso coffee maintains the beverage′s physicochemical stability and enhances its antimicrobial activity, with C. citratus as the most promising additive for functional beverages.