Study of alternatives for the valorization of coffee pulp

This comprehensive study delves into the valorization of a coffee by-product, focusing on coffee pulp carotenoids and antioxidant activity and their application in food products. In first place, using microwave-assisted extraction (MAE), optimized conditions were established to maximize yield and carotenoid concentration. The optimal parameters were determined to be 364 W for 105 seconds using a solvent ratio of 20% ethanol and ethyl acetate, resulting in an extraction yield of 6.54 ± 0.48%, a carotenoid concentration of 5.72 ± 0.51 mg β-carotene/g extract, and a carotenoid recovery of 54.52 ± 1.69%. The extracted carotenoids were then encapsulated by freeze-drying, producing particles with an average size of 1.249 ± 0.210 µm. These encapsulated carotenoids were incorporated into gummies, which showed altered color but unaltered textural properties. In a parallel study, the potential of coffee pulp as a raw material for kombucha fermentation was explored. The research compared the fermentation kinetics, phenolic content, and antioxidant activity of kombucha brewed from dried and fresh coffee pulp with that brewed from black tea. Dried pulp kombucha produced more ethanol (1.53 ± 0.10%) and consumed more sugar (3.80 g/100mL) than fresh pulp kombucha (0.64 ± 0.04% ethanol and 0.61 g/100mL sugar). Fresh pulp kombucha showed higher total phenols (71.24 ± 2.27 mg eq GAE/330 mL) and antioxidant activity (4.03 ± 0.08 mmol Trolox eq/mL) compared to dried pulp kombucha (67.14 ± 3.18 mg eq GAE/330 mL and 2.16 ± 0.09 mmol Trolox eq/mL, respectively). The phenolic profile showed higher concentrations in fresh pulp kombucha, except for rutin and, the alkaloid, caffeine, which were higher in dry pulp kombucha. The pH levels ranged from 2.67 ± 0.02 in fresh pulp kombucha to 3.21 ± 0.08 in dried pulp kombucha, with black tea kombucha at 2.98 ± 0.01. Soluble solids were highest in fresh pulp kombucha (11.33 ± 0.32 °Brix), followed by dry pulp (7.10 ± 0.36 °Brix) and black tea (5.30 ± 0.10 °Brix). A market analysis shows that the global kombucha market is expected to grow to US$11 billion by the end of the decade, with a shift in consumer preferences towards small businesses and flavored, health-promoting kombuchas. This study clears the way for using coffee processing residues in the formulation of final products, offering a novel avenue of resource generation for coffee producers in Colombia and around the world.

Maestría

Valorización de subproductos agroindustriales