Valorization of Coffee Pulp: Spray-Dried Hemp Oil Microcapsules Stabilized with Coffee Pectin and Maltodextrin

The global challenge of food waste presents an opportunity to explore the untapped potential of agricultural by-products. Coffee pulp, a major by-product of the coffee industry, is a promising source of functional polysaccharides such as coffee pectin, which can be valorized for sustainable applications in food systems. This study investigates the microencapsulation of hemp seed oil—rich in essential fatty acids and bioactive lipids—using coffee pectin and maltodextrin as wall materials via spray drying. Emulsions with varying oil-to-wall ratios were formulated and characterized for viscosity, particle size, and zeta potential. The resultant microcapsules were analyzed for physicochemical properties, encapsulation efficiency, oxidative stability (peroxide value), and in vitro release in simulated gastrointestinal fluids. Encapsulation efficiencies ranged from 63.27% to 70.77%, with lower oil content formulations exhibiting higher efficiency. The peroxide values indicated enhanced oxidative stability, with the lowest value (10.69 meq O 2 /kg oil) observed in the most efficient encapsulation formulation. Microcapsule morphology analysis confirmed the formation of spherical particles with varying degrees of surface roughness. Release studies demonstrated controlled oil delivery, with higher retention in gastric conditions and progressive release in intestinal fluids. These findings demonstrate the potential of upcycled coffee pulp-derived pectin as a functional, sustainable encapsulant, aligning with circular economy principles and supporting the development of stable bioactive delivery systems for nutraceutical and food applications.