The use of Moringa oleifera waste material for the development of an edible buiofilm for prolonging the shelf-life of 'Keitt' Mango fruit

Abstract

The development of plant-based edible coatings for preserving postharvest quality in mangoes is a crucial step toward reducing reliance on synthetic coatings, which pose environmental and health concerns. This study explored the potential of Moringa oleifera (moringa) waste, a by-product rich in bioactive compounds, as a key ingredient in developing an eco-friendly edible coating to extend the shelf life of mangoes. By repurposing moringa waste into a value-added product, this research aligns with sustainable agricultural practices and promotes a circular economy by transforming agricultural by-products into functional resources for food preservation. The study had two primary objectives: (a) to assess the impact of different drying methods and extraction solvents on the phenolic content, antioxidant properties, and antifungal activity of moringa waste extracts, and (b) to evaluate the effectiveness of Opuntia ficus-indica mucilage (OFIM) enriched with moringa waste extracts as an edible coating in preserving mango quality during storage. The first phase of the study assessed the effect of sun drying (SD), oven drying (OD), and freeze drying (FD) in combination with different solvent extractions (distilled water, 50% ethanol, and 100% ethanol) on moringa waste extracts. The results indicated that oven drying coupled with 50% ethanol extraction (OD-EtOH50%) was the most effective treatment for retaining phenolic content (TPC = 55.48 mg GAE/g), antioxidant capacity (ABTS IC50 = 0.89 mg/mL), and antifungal activity against Botrytis spp. (MIC = 0.375 mg/mL). Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) profiling identified chlorogenic acid, quercetin-4’-glucoside, kaempferol-3-(6-acetylgalactoside), rutin, and caffeoylquinic acid derivatives as dominant phenolic compounds in moringa waste, with significant variations depending on the drying and extraction method used. The findings demonstrated that thermal drying methods (OD and SD) in combination with hydroalcoholic solvents (EtOH50%) are optimal for extracting bioactive compounds, supporting their use in food preservation applications. The second phase of the study evaluated the postharvest efficacy of OFIM coatings enriched with moringa waste extracts in maintaining mango quality at ambient storage conditions. Results revealed that edible coatings enriched with oven-dried (OD-ME) and freeze-dried (FD-ME) moringa extracts significantly reduced weight loss, decay incidence, respiration rate, and ion leakage compared to untreated control fruits. By day 12, mangoes coated with OFIM+FD ME had the lowest respiration rate (9.58 mL CO₂/kg/h) and decay incidence (18.5%), while control fruits exhibited higher iii respiration (20.90 mL CO₂/kg/h) and decay (58.4%). Furthermore, OFIM+FD ME and OFIM+OD ME coatings successfully maintained firmness (4.8 N and 4.3 N, respectively), total phenolic content (TPC = 37.9 mg GAE/g and 35.5 mg GAE/g), radical scavenging activity (RSA = 85.6% and 81.2%), and ferric reducing antioxidant power (FRAP = 0.88 mg Fe²⁺/g and 0.79 mg Fe²⁺/g) throughout storage. These coatings delayed mango ripening by up to 8 additional days compared to uncoated fruits, while coatings with OFIM alone and OFIM+SD ME extended shelf life by only 4 days. The ability of moringa waste extracts to enhance antioxidant and antimicrobial properties in edible coatings demonstrates their potential as natural preservatives, reducing reliance on synthetic chemicals. The study also reinforces the economic feasibility of oven drying (OD), which offers a cost-effective alternative to freeze drying (FD) while maintaining high bioactive compound retention. By utilizing agricultural by-products, this study promotes sustainable food preservation strategies that align with the principles of a circular economy. In conclusion, the findings of this study highlight the effectiveness of OFIM enriched with moringa waste extracts as a sustainable and natural alternative for postharvest preservation. The integration of bioactive-rich moringa waste into edible coatings not only reduces food loss and spoilage but also supports global sustainability goals such as SDG 12 (Responsible Consumption and Production) and SDG 2 (Zero Hunger). The practical implications of this study suggest that moringa-enriched coatings can be commercialized for the fruit industry as an eco-friendly solution to extend the shelf life of perishable produce. Future research should focus on sensory evaluation, toxicity assessment, and the application of these coatings on other horticultural crops to expand their commercial viability and maximize their contribution to global food security.