Enhancing the functional properties of chitosan-alginate edible films using spent coffee ground extract for fresh-cut fruit preservation.

The developed edible film, formulated using sodium alginate, mushroom-derived chitosan, and bioactive-rich coffee ground extract, offers an environmentally friendly approach to food preservation. By utilizing agro-industrial byproducts, the formulation demonstrates potential economic and social benefits aligned with sustainable development goals. This study developed and optimised a sustainable edible film incorporating spent coffee ground extract (SCGE) as an active ingredient. The formulation was optimised through response surface methodology employing a central composite design, wherein chitosan (0.5-2.5 % w/v), sodium alginate (0.5-2.5 % w/v), glycerol (0.5-2.5 % v/v), and SCGE (4-12 % v/v) were systematically varied. The optimal film (1.49 % chitosan, 1.12 % sodium alginate, 1.53 % glycerol, and 9.69 % SCGE) exhibited enhanced mechanical strength (6.33 MPa), hydrophobicity (78.31° water contact angle), and antioxidant capacity. Spectroscopic analysis confirmed strong polymer-SCGE interactions, improving structural integrity and stability. Applying the coating to fresh-cut kiwi fruit notably decreased moisture loss by 37.5 %, delayed spoilage, and maintained appearance, and physicochemical characteristics over 10 days of cold storage at 4 °C. These results found SCGE-based edible films as an eco-friendly and functional packaging alternative, utilizing agro-industrial waste to enhance food quality, extend shelf life, and promote sustainability in contemporary food packaging.