Production and characterization of a new distillate obtained from fermentation of wet processing coffee by-products

Abstract

Coffee is one of the most important commodities worldwide. The industrial processing of coffee cherries generates a considerable volume of by-products such as wastewater, coffee pulp, mucilage, and husk. These by-products have sugars and nutrients that can be converted into value-added products via microbial action. In this study, for the first time, we evaluated the potential of coffee pulp and coffee wastewater as substrate for alcoholic fermentation produce a distilled beverage. The must composed by dry or wet coffee pulp and coffee wastewater added of commercial sucrose or sugarcane molasses was fermented by S. cerevisiae. After a screening step, a larger fermentation was carried out with the wet pulp added of sucrose due to its higher alcoholic fermentation efficiency. The distilled beverage contained 38% (v/v) ethanol and 0.2 g/L of acetic acid. The contaminants furfural, hydroxymethylfurfural and ethyl carbamate were below detection level. Among the 48 volatile compounds detected, the majority (21) were ethyl esters usually associated with floral and sweet aromas. Ethyl decanoate (996.88 µg/L) and ethyl dodecanoate (1088.09 µg/L) were the most abundant esters. Coffee spirit presented taste acceptance of 80% and sugarcane spirit, 70%. The tasters indicated an aroma acceptance of 86% for the coffee spirit and 78% for the sugarcane spirit. The results of this work demonstrate the potential for using coffee by-products to produce a good quality distilled beverage. Considering our results, especially sensorial analysis, we can infer that the produced coffee beverage represents a new alternative for adding value to the coffee production chain.