Green Chemistry Applied to Ground Coffee Volatile Compounds Modification Aiming Coffee Aroma Improvement

Abstract

Aroma has a major role in coffee acceptance by consumers. This work has assessed the application of cold plasma technology to induce modifications in ground coffee beans without resorting to solvents or additives, thus applying a green chemistry approach. Cold plasma improved and modulated coffee aroma, increasing desirable and decreasing undesirable aroma notes. Ground coffee beans were subjected to dielectric-barrier discharge (DBD) plasma at different excitation frequencies. Its volatile chemical profile was determined by GC-MS. The odor activity value technique was used to evaluate the aroma profile. Extensive chemical changes occurred with aldehydes, furans, and pyrazine compounds. This work showed that setting proper excitation frequency enables modulating changes toward oxidation and C-C bond scission. Chemical reaction pathways were postulated and discussed. DBD plasma technology enhanced the importance of the desirable cocoa note from 74.4 to 88.6% and decreased the significance of the green and fruity notes from 8.5 to 3.2% and 2.7 to 1.9%, respectively. Plasma-induced reactions can help mitigating aroma defects.