Enhancing the Water Resistance of Carboxymethyl Cellulose Films with Cellulose Nanofibers from Spent Coffee Grounds and Grapeseed Oil

Abstract The development of edible films that can act as individual barrier layers for food could be a practical solution to minimize food deterioration and loss. Among the film-forming materials, polysaccharides are strong biopolymer candidates owing to their numerous advantages. However, their poor ability to function as a barrier to water molecules restricts their applications. To overcome this major shortcoming, the present study tested the potential of non-oxidized cellulose nanofibers (CNFs) extracted from spent coffee grounds (SCG) to function as nanoscale fillers and stabilizers for a lipophilic component in a polysaccharide-based film, with the main aim of reducing the water vapor permeability (WVP). CNFs and grapeseed oil (GSO) were embedded in carboxymethyl cellulose (CMC) matrix to formulate polysaccharide-based films with enhanced water barrier characteristics. The physicochemical and antimicrobial properties of the films were analyzed. The composite films resulted in significantly lower affinity to water and enhanced mechanical properties without significantly impairing the visual appearance of the films. Moreover, the oil-containing films were found to have the potential to reduce bacterial spoilage. These findings propose a sustainable approach to using food waste to develop polysaccharide-based films with enhanced water resistance. They also provide a framework for creating polysaccharide films with improved water vapor barrier and mechanical properties.