From waste to packaging: Smart edible films from sericin and red cabbage for fruit coating

ABSTRACT This study aimed to develop new smart edible films for fruit preservation and freshness monitoring using sericin, an undervalued by-product of the sericulture industry, and red cabbage extract (RC). The films were prepared using a sodium alginate matrix, and two sets of films were developed. One incorporating sericin, and other incorporating sericin and RC. Chemical and mechanical characterization showed that sericin improved film thickness, mechanical strength, and water retention. The films also exhibited acceptable water vapor transmission rates and swelling behavior, showing their suitability as coatings. The cytotoxicity was assessed prior to application, and no toxic effects were observed in human fibroblasts. When applied to blueberries, the coatings significantly reduced weight loss during storage at both room temperature and under refrigeration. Although no visible color changes were observed on the coated blueberries, the RC-containing films demonstrated clear pH-responsive color changes in laboratory tests, highlighting their potential as intelligent freshness indicators. Overall, the results demonstrate the dual functionality of these films as biodegradable protective coatings with indicator potential, offering a sustainable approach to reducing postharvest fruit losses and food waste.