Development of Novel Pectin-Based Films from Coffee Waste:Mucilage and Pulp

Coffee is the world’s second-most preferred beverage and a highly commercialized agri-food product. During its production, a significant volume of post-harvest and processing waste is produced. In this study, post-harvest coffee waste was processed to develop a novel pectin-based film reinforced with bacterial cellulose obtained by the fermentation from coffee mucilage and coffee oil extract of spent coffee grounds (SCG). Pectin from coffee waste (coffee mucilage and coffee pulp) was isolated by citric acid hydrolysis. The addition of bacterial cellulose and coffee oil (SCGE) to the formulation of the pectin-based films improved the physicomechanical properties, flexibility, and functionality (tensile strength 3.4 MPa, elongation at break 24.5%, resistance of water solubility 40%, and spontaneous degradation during 16 days in soil under uncontrolled conditions). The reinforced films based on pectin from coffee pulp showed better properties when compared to pectin-based films from coffee mucilage (tensile strength of 2.2 MPa and water solubility of 58.5%); this effect is attributed to the morphological characteristics and the presence of pores in the polymeric matrix of pectin-based films from coffee mucilage. According to the results, these composite films hold great promise as substitutes, for example, for single-use plastics while giving value to underexplored coffee residues.