COFFEE FERMENTATION: INFLUENCE OF TEMPERATURE CONTROL ON PHYSICOCHEMICAL PARAMETERS OF THE FRUIT

Coffee fermentation has proven to be an important tool for improving the beverage’s sensory quality. To understand how this process alters coffee characteristics, studies on different fermentation methods are necessary. This study aimed to evaluate the physicochemical characteristics of coffee fruits fermented in reactors with and without temperature control. Arabica coffee, cultivar Arara, grown at the Federal University of São João Del Rei, Sete Lagoas-MG campus (19°28′4″S, 44°14′52″W), was used. The fruits were harvested, washed, and placed in closed bioreactors of 2 L (B2) and 8 L (B8). Fermentation occurred without temperature control in B2 and with temperature control at 27°C in B8, using a water bath and a water recirculation pump into the reactor. At the beginning and end of fermentation, temperature was measured and fruit samples were collected to determine moisture, titratable acidity, ash, protein, and lipid content, following the official methodology of the Association of Official Analytical Chemists. Experiments were performed in triplicate for B2 and once for B8, with sampling at three different positions in the latter. All analyses were performed in triplicate. Fermentation promoted changes in the physicochemical composition of the fruits, and the type of fermentation influenced the results. The initial moisture content of 52.1% was reduced to 50.25% in B2 and 38.27% in B8. Ash content also decreased from 4.9% (0h) to 4.3% (48h) in B2 fermentation, reaching 4.1% in the B8 bioreactor. A decrease in lipid content was observed from 2.9% to 2.7% in B2; however, B8 showed an increase to 3.8%. Initially, the protein content in the fruits was 17.8%, remaining stable at 17% in B2 fermentation, but dropping to 14.9% in B8. Finally, titratable acidity remained stable between 0h (113.55 mg acid/100g) and 48h (112.211 mg) in B2 fermentation but increased to 129.0376 mg in B8, indicating more intense fermentation and greater production of organic acids. These results show that the reactor with temperature control promoted more pronounced changes in the coffee matrix, probably due to the constant temperature maintenance, which may directly impact the beverage’s sensory profile.