Coffee mucilage clarification: A promising raw material for the food industry

Abstract

Coffee mucilage is a by-product of interest for its potential for producing antioxidant beverages. This study examined the effect of operating conditions on coffee mucilage clarification to improve the process and transform it in a raw material. A 24 Full Factorial Design (FD) with a central point was used to evaluate the incubation times (6–140 h), clarifying agent concentrations (0.1–1.5 mg/mL), pH (4.0–5.5), and temperatures (21–60 °C) for gelatin and enzymatic treatment on mucilage turbidity, total content of phenolic compounds (substances having an aromatic ring with one or more hydroxyl groups), protein, and carbohydrate content. The statistical analysis of the results was conducted by means of a variance analysis (ANOVA) with 95 % reliability. Gelatin treatment reduced coffee mucilage turbidity by 46–57 % but presented a 39 % reduction in total phenolic content. Statistical analysis showed the enzymatic treatment (pectinase) as the best evaluated clarifying agent, with a 63.7 % decrease in turbidity (0.744 ± 0.021) without significantly affecting the total phenolic content. Pectinase concentration and pH were the factors that most affected the process, suggesting operating conditions of pH 4, 1.1 % pectinase concentration, process temperature 21 °C, and 30 min incubation time.