Valorisation of fresh produce waste into a sodium alginate-based vegan, bioinspired edible coating for strawberry preservation.

As global food demand continues to rise, the fruit processing industry generates substantial quantities of high-value waste. In response, scientific efforts are increasingly directed toward zero-waste strategies that valorise by-products within a circular economy framework. This study aimed to optimise and develop bioinspired, vegan edible films based on sodium alginate, incorporating varying concentrations of fruit processing wastes as functional ingredients. Response Surface Methodology (RSM) was used to optimise the effect of citrus waste powder (0.5-2.5% w/v), apple pomace powder (0.5-2.5% w/v), and carnauba wax/coconut oil (2.0-5.0% v/v) on the film tensile strength, thickness and water contact angle. The optimised formulation comprising 1.10% citrus waste powder, 1.40% apple pomace powder and 3.50% carnauba wax/coconut oil solution exhibited improved mechanical strength (7.04 MPa and 29.59% elongation), surface hydrophobicity (water contact angle - WCA of 75.84°), UV-light barrier properties, and increased antioxidant activity. Fourier transform infrared (FTIR) analysis confirmed strong intermolecular interactions among the sodium alginate matrix, fruit waste-derived powders, and hydrophobic additives, thereby improving the structural integrity and stability of the biopolymer film. Furthermore, when applied to fresh strawberries, the optimised edible coating significantly delayed microbial spoilage, retained colour and internal moisture, and preserved natural sweetness over a 10-day storage period at 4 °C. Compared to uncoated fruits, a 4-day shelf-life extension was achieved. These findings support the viability of circular economy strategies in the sustainable development of multifunctional edible films and coatings derived from fruit processing waste for effective food preservation.