Development of biotechnological products from coffee by-products using the biorefinery concept

Abstract

Coffee is an important commodity worldwide, representing a significant portion of economy of several countries. The processing of coffee fruits generates a great variety and volume of by-products, such as husk, pulp, and coffee grounds. In recent years, environmental and social concerns have grown in relation to the direction and use of these by-products. They are nutrient-rich substrates that can be converted into products with higher added value via microbial action. Therefore, this study aimed to evaluate coffee by-products as alternative substrates in alcoholic fermentation and the development of new biotechnological products. The first article evaluated the use of dry and wet coffee pulp, wastewater from wet coffee processing, molasses, and commercial sucrose as substrates in alcoholic fermentation. The wet coffee pulp and sucrose treatment resulted in the best fermentation performance, and the conditions were applied to produce a distilled beverage. The beverage had an alcohol content of 38 % (v/v) and 48 volatile compounds were identified, the majority being esters normally associated with floral and fruity aromas. The second article consisted of a pilot-scale production of two distilled beverages using the by-product generated during the production of coffee oil. Fermentations of 40 liters were carried out with 10% e 20% (m/v) of green coffee seed residue, followed by distillation in copper alembic. A total of 62 volatile compounds were identified, the majority being affected by variation in the concentration of green coffee seed residue. In the sensory analysis, the beverage with a concentration of 10% (m/v) was characterized by floral, dairy, and almond aromas, while the beverage with 20% was related to coffee, vegetables, cooked cabbage, hazelnuts, and nuts aromas. Both beverages showed satisfactory results, especially with 10% (m/v) of the residue, demonstrating the potential for using this residue in the production of distilled beverages. In addition, the vinasse obtained from the second study was used in preliminary studies in order to recover chlorogenic acid. The vinasse had an initial concentration of 3.16 g/L of chlorogenic acid, and the final extract had 11.96 g/L of it, concentrating the compound of interest 3.9 times. Lastly, there is the application for filing a patent where a distillate obtained from coffee beans was applied as an attractive solution to control the coffee berry borer. Lastly, there is the use of distillate obtained from coffee beans as an attractive solution to control the coffee berry borer. The invention made it possible to monitor and control the pest without the need to use insecticides and toxic compounds in the field.