Sustainable recovery of active compounds from coffee husks using enzymatic aqueous extraction

Abstract This study aimed to evaluate the effectiveness of aqueous extraction combined with the use of the enzyme Viscozyme ® L for the recovery of compounds from coffee husks. Therefore, initially, extractions were conducted to determine the condition for maximum extraction of total phenolic acids (TPA), based on the effect of the variables enzyme concentration (1 wt% to 5 wt%), temperature (45 °C to 55 °C), and time (20 to 60 min). Subsequently, extractions were performed with and without enzyme at different times, obtaining the yield, composition, antimicrobial activity and cytotoxicity of the dry extract. Based on the results, maximum TPA extraction was observed at 45 °C, 60 min, and with 1 wt% of enzyme. The use of the enzyme (1wt%) in the extraction medium provided an increase in the yield of dry extract from 10 to 43% at the evaluated times (20 to 60 min), in addition to resulting in extracts with greater antioxidant potential and higher levels of phenolic compounds, when compared to aqueous extraction alone. The extract was composed by phenolic acids and kaempferol, being chlorogenic acid the most abundant compound. A high correlation was found between chlorogenic acid and antioxidant potential ( r = 0.98). The extract exhibited bacteriostatic activity, with a minimum inhibitory concentration (MIC) ranging from 8.33 to 10.00 mg/mL. The application of the extract, at the tested concentrations (50 to 400 µg/mL), did not compromise the viability of HaCaT cells.