Extração aquosa enzimática de compostos bioativos do grão de café verde e torta residual da extração por prensagem mecânica

Abstract

Agribusiness generates large amounts of waste that are often discarded or not used conveniently and sustainably. During the mechanical extraction of the green coffee oil, biomass is generated, which still contains bioactive compounds and oil. For the extraction of desirable compounds, the aqueous process is shown as an alternative that aims at the health of the manipulators and consumers, reducing the use of organic solvents. The present work was carried out with the objective of evaluating the aqueous enzymatic extraction process by carbohydrases in the green coffee bean and its residual cake resulting from the mechanical extraction of its oil. The time, pH and temperature factors were optimized in the extraction of soluble solids with a central rotational composite design (CRCD). After the optimization, the extract produced under these conditions was characterized by physical-chemical analysis and compared with aqueous extraction under the same conditions, except for the use of enzymes. The correlation between physical-chemical analyzes was verified using Pearson's coefficient. The results of the optimization of the enzymatic extraction of the soluble solids for the coffee bean were 75 minutes, pH 4.5 and temperature of 49 °C, and for the residual cake of 51 minutes, pH 5 and temperature of 46 °C. The comparison with the control group (aqueous extraction without the use of enzymes) showed that the addition of enzymes favored the extraction of caffeine, phenolic compounds, oil and the antioxidant activities ABTS and DPPH, and with the potential to use residual cake in view of similar results and even superior when compared to the coffee bean. The Pearson's linear correlation coefficient identified the parameters that correlate in the enzymatic process and showed that the extraction of phenolic compounds is correlated with the presence of caffeine, reducing sugars and antioxidants by the DPPH methodology, whereas turbidity is correlated with the presence of oil and caffeine in the extract phase. ABTS and DPPH methodologies for antioxidants did not present a statistically significant correlation between them. The use of enzymes increased the extraction of compounds of interest and cake, as a use of agro-industrial residues in the coffee market, proved effective, since its application as a matrix reduces waste and consequently the cost of material, with results even superior in caffeine, phenolic compounds and antioxidant activity by DPPH concerning the coffee bean.