Elaboration of distilled beverage from spent coffee ground

摘要

Spent coffee ground (SCG) is the solid residue obtained from the treatment of coffeepowder with hot water to prepare instant coffee, and constitutes the main coffee industry residue.Finding alternatives for the reuse of this residue is of great interest from economical andenvironmental viewpoints. The goal of the present study was to use this residue as raw material forthe production of a new distilled beverage. The process for elaboration of this beverage consisted inan initial extraction of the aromatic compounds from SCG with water, followed by the fermentation ofthis extract in a bench bioreactor and subsequently distillation of the fermented broth. The produceddrink contained 40% v/v ethanol, and presented mild coffee flavor. Several volatile compounds wereidentified in this distillate among of which, higher alcohols were quantitatively the most abundantgroup. Isoamyl alcohol (3-methyl-1-butanol), isobutanol (2-methyl-1-propanol), and 2-methyl-1-butanol were the higher alcohols found in major quantities (810, 269, and 185 mg/l, respectively),contributing thus for the greatest proportion of the total aroma and essential character. Ethyl acetateand acetaldehyde, which are also volatile compounds of large influence on the flavor of alcoholicbeverages, were found in SCG distillate in concentrations of 38 mg/l and 80 mg/l, respectively. Onthe other hand, methanol that is a compound harmful to the health was found at low level (11 mg/l).Considering the flavor, the volatile compounds present, and the ratio between isoamyl alcohol/2-methyl-1-propanol and 2-methyl-1-propanol/1-propanol, which are indicative of the quality ofalcoholic beverages and have to be higher than unity, it was concluded that a novel spirit ofacceptable organoleptic character can be produced by fermentation using SCG as raw material.