Dados do Trabalho

Título

COMPARISON OF THE CHEMICAL COMPOSITION OF FERMENTED AND NON-FERMENTED GREEN COFFEE BEANS

Introdução

During fermentation, biochemical reactions in coffee fruits consume sugars and produce metabolites such as alcohols and organic acids. These compounds persist in the coffee beans and act as sensory precursors, contributing to the quality and complexity of the beverage. Therefore, the aim of this study was to investigate the relationship between the composition of sugars, alcohols and organic acids in fermented and non-fermented Arabica cv. Acauã coffee beans.

Material e Métodos

Coffee cherries were fermented in solid state in a 15000 L stainless steel bioreactor for 48 h at controlled temperature (27±0.5°C). Non-fermented cherries (control sample) and fermented fruits were sun-dried (until a moisture content of 12%). Dried fruits were peeled, and the beens were retained for determination of sugars, organic acids, and alcohols by high-performance liquid chromatography. For obtaining data averages and standard deviations, statistical analyses were applied using the software Minitab®️ 17.1.0 by ANOVA followed by the Tukey Test (p-value≤ 0.05).

Resultados e Discussão

Sugars and alcohols concentrations for the control and fermented samples were, respectively: sucrose (7.59±0.28 mg/g)a and (9.74±1.37 mg/g)a, glucose (0.91±0. 04 mg/g)b and (2.23±0.30 mg/g)a, fructose (1.80±0.03 mg/g)b and (4.17±0.53 mg/g)a, glycerol (0.15±0.06 mg/g)b and (0.42±0.03 mg/g)a, ethanol (0.02±0.01 mg/g)b and (0.10±0.01 mg/g)a. For the acids, concentrations obtained were: citric acid (1.49±0.02 mg/g)b and (2.36±0.16 mg/g)a, malic acid (0.53±0.004 mg/g)b and (0.78±0.03 mg/g)a, succinic acid (0.06±0.02 mg/g)b and (0.25±0.06 mg/g)a , lactic acid (2.26±0.002 mg/g)b and (5.53±0.59 mg/g)a and for acetic acid (0.02±0.003 mg/g)b and (0.22±0.01 mg/g)a. Sucrose showed no significant changes in either sample, however, the concentrations of glucose and fructose increased significantly in the fermented grains due to the hydrolysis reactions of sucrose. There was also a significant increase in the concentrations of alcohols and acids in the fermented grains, indicating the predominance of metabolites produced during the fermentation process inside the green grain. The accumulation of metabolite precursors in green coffee beans can affect the sensory quality of coffee, varying according to their composition and concentration. These components significantly impact the final quality of the beverage, influencing characteristics such as acidity, aroma, flavor, and texture.

Conclusão

Sucrose showed no significant changes in either sample, however, the concentrations of glucose and fructose increased significantly in the fermented grains due to the hydrolysis reactions of sucrose. There was also a significant increase in the concentrations of alcohols and acids in the fermented grains, indicating the predominance of metabolites produced during the fermentation process inside the green grain. The accumulation of metabolite precursors in green coffee beans can affect the sensory quality of coffee, varying according to their composition and concentration. These components significantly impact the final quality of the beverage, influencing characteristics such as acidity, aroma, flavor, and texture.