Functional Textiles and Natural Colourants Derived from Agro Food Waste: A Comprehensive Review of Their Application in Food Quality Monitoring, Active Packaging, and the Circular Bioeconomy

Abstract

The global food system faces a dual sustainability crisis: huge quantities of agro‑food waste are generated annually, while food safety monitoring and preservation remain heavily dependent on resource‑intensive, non‑renewable materials and methods. This review explores the emerging interdisciplinary field that connects textile engineering, natural colourant chemistry, and food science. We provide a comprehensive and critical synthesis of more than 120 peer‑reviewed studies published between 2020 and 2026. The paper is organised around three interconnected pillars. First, we examine the valorisation of agro‑food residues – including mango seed kernel, Aronia pomace, orchid blooms, grape pomace, pomegranate peels, and Stevia leaves – as sources of natural colourants (anthocyanins, carotenoids, flavonoids, tannins) and bioactive finishing agents. Quantitative data are presented on extraction efficiencies (ultrasound‑assisted vs. conventional), dyeing performance on various textile substrates (cotton, wool, silk, viscose, bacterial cellulose), and functional properties (antioxidant activity measured by DPPH and ABTS assays; antibacterial efficacy against Escherichia coli and Staphylococcus aureus; colour fastness to washing, light, and rubbing). The best‑performing systems achieve DPPH scavenging >98%, ABTS >99%, and bacterial reduction >99%, with colour fastness ratings of 4–5 on the ISO scale. Second, we review textile‑based sensor platforms developed for real‑time, on‑site food quality monitoring. These include: (i) cotton fabrics functionalised with molecularly imprinted polymers (MIPs) and nitrogen‑doped carbon dots (N‑CDs) for fluorescence detection of carbamate pesticides (detection limit 3.38 μg/L for carbofuran); (ii) covalent organic framework (COF)‑modified textile sensors that exhibit solid‑state chromism for time‑temperature indication (−22 °C to 55 °C) and nanozyme activity for mycotoxin detection at sub‑ppb levels; (iii) electrospun nanofibre mats incorporating pH‑sensitive dyes for visual spoilage monitoring; and (iv) bacterial cellulose (BC) with in‑situ biosynthesis of colourants for intelligent packaging. We compare analytical performance, reusability, and scalability. Third, we evaluate the application of these functional textiles in intelligent and active food packaging. Case studies show that COF‑composite films extend the shelf life of beef and kumquat by fourfold, and coloured BC trays reduce microbial contamination without synthetic preservatives. A dedicated section critically discusses safety concerns related to heavy metal contamination of plant‑derived materials, drawing on extensive Iranian studies (Alinia‑Ahandani et al., 2020–2026) that have documented elevated lead, cadmium, and other toxic elements in medicinal plants and food products. We propose a quality control framework for plant‑based colourants intended for food‑contact applications. The review concludes with a research agenda that includes standardisation of test methods, life‑cycle assessment, hybrid nanoparticle–plant extract systems, field validation, and regulatory harmonisation.