Influence of the Ratio Between Arabica Coffee Pulp and Green Coffee Bean Extract on Physicochemical, Functional and Nutritional Properties of Instant Coffee Pellet Cube
ABSTRACT Coffee ( Coffea spp. ) is a tropical plant cultivated globally and plays an important role in the economies, livelihoods, and cultures of regions such as Latin America, Africa, and Southeast Asia. However, the part other than coffee beans, estimated at approximately 42 million metric tons, is typically unused. This study aims to evaluate the influence of the ratio between Arabica coffee pulp and green coffee bean aqueous extract, as coffee by-products, on the physicochemical, functional, and nutritional properties of freeze-dried instant coffee pellet cubes. The results show that increasing the ratio of coffee pulp extract can reduce lightness (L*), yellowness (b*), chroma, and hue in instant coffee cube, and also increases bulk density and thermogravimetric value. The coffee pulp extract ratio significantly influences the solubility of the product. As the percentage of coffee pulp extract in the product increased from 20% to 100%, the solubility improved from 38.79% to 52.26% at room temperature and from 83.56% to 87.59% at 60 °C, respectively. The antioxidant activity of the instant coffee cubes decreased from 7.59 to 5.89 mM Fe (II)/g in the FRAP assay and from 6.57 to 3.89 mM/g in the ABTS assay, which is consistent with the observed reduction in total phenolic content, from 778.12 to 657.89 mg GAE, as well as other phytochemicals. However, the addition of coffee pulp extract also improves the nutritional value, particularly protein content, which increased from 6.47% to 11.02%. Overall, the findings support the potential use of coffee pulp as a sustainable and nutrient-rich component for instant coffee production.