Opuntia ficus-indica mucilage coating prolongs the shelf life of bananas (Musa spp.) by enhancing antioxidant activity and modulating antioxidant enzyme systems

Bananas are one of the most significant tropical fruits in the world market. However, their short postharvest life, particularly under retail conditions exceeding 20 °C, results in significant economic losses and food waste. This study investigated the efficacy of Opuntia ficus-indica mucilage (OFIM) as an edible coating to enhance the antioxidant defense mechanisms and prolong the postharvest life of bananas under simulated retail conditions (21 ± 1 °C, 85 ± 2% relative humidity). The experimental design included untreated (control) bananas and those coated with 1%, 2%, or 3% OFIM. Key quality parameters, including water vapour permeability, reactive oxygen species (ROS; superoxide [O₂⁻] and hydrogen peroxide [H₂O₂]), total phenolic content (TPC), total flavonoid content (TFC), ascorbic acid (AA), and antioxidant activities (DPPH, FRAP, ABTS⁺), were assessed every three days for 18 days. Enzymatic activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) were also monitored. The results demonstrated that OFIM coatings significantly extended banana shelf life by up to six days compared to untreated samples. Coated bananas exhibited enhanced antioxidant activities (DPPH, FRAP, ABTS⁺), increased levels of TPC, TFC, and AA, and elevated enzymatic activities of CAT, SOD, and PAL. Additionally, PPO and POD activities were suppressed, reducing oxidative damage caused by ROS. Among the tested concentrations, 3% OFIM exhibited superior preservation efficacy. These findings demonstrate that OFIM is a sustainable, cost-effective, and environmentally friendly solution for reducing postharvest losses and promoting food security in commercial banana markets.