Recent advances in sustainable extraction of plant pigments from fruit and vegetable peel waste for smart packaging applications in food freshness monitoring

The increasing volume of fruit and vegetable peel waste (FVPW), a by-product of rising horticultural production and processing, presents a significant opportunity for value addition in food technology. Rich in bioactive compounds such as anthocyanins, betalains, carotenoids, and chlorophylls, FVPW serves as a promising source of natural pigments. This review focuses on the extraction of these pigments using conventional (solvent extraction, maceration) and advanced techniques (ultrasound-assisted, microwave-assisted extraction), and their subsequent application in intelligent food packaging systems. Specifically, these pigments can function as pH-sensitive colorimetric indicators to monitor spoilage and freshness in perishable foods. The integration of FVPW-derived pigments into biopolymer-based films offers a dual benefit, enhancing packaging functionality while contributing to environmental sustainability by reducing agro-industrial waste. This review underscores the potential of pigment-based sensors from FVPW in developing next-generation active and smart packaging solutions. Utilizing FVPW pigments in such innovations can help reduce food waste, minimize losses, and reduce their environmental impact.