Valorization of red Coffea arabica var. Caturra pulp

Kombucha is a fermented beverage traditionally made from tea. This study investigates the use of coffee pulp —a polluting by-product of coffee processing— as an alternative to tea in kombucha development. The research aimed to compare kombucha made from dried and fresh coffee pulp with traditional black tea kombucha, focusing on ethanol production, sugar consumption, phenolic content, antioxidant activity, caffeine levels, and pH. The results indicated that dried coffee pulp kombucha produced more ethanol (1.53%) and consumed more sugar (3.80 g/100mL) than fresh pulp kombucha (0.64% ethanol, 0.61 g/100mL sugar). However, fresh pulp kombucha had higher total phenols content (71.24 mg eq GAE/330 mL) and antioxidant activity (4.03 mmol Trolox eq/mL) compared to dried pulp kombucha. Additionally, the fresh pulp version had a higher concentration of catechins, whereas the dried pulp kombucha had greater caffeine content. In terms of pH, fresh coffee pulp kombucha had the lowest value (2.67), followed by black tea kombucha (2.98), and dried pulp kombucha had the highest pH (3.21). Fresh pulp kombucha also presented the highest level of soluble solids (11.33 °Brix). The study concludes that fresh coffee pulp kombucha, with superior antioxidant properties and phenolic content, holds the most promise. This innovation could create new economic opportunities for coffee producers in Colombia and globally, as the kombucha market continues to grow.