Pectin-rich purple passion fruit mesocarp/agarose: film properties and impact of coatings on banana preservation

Abstract

This work aimed to extract pectin from purple passion fruit mesocarp (PPMP) and then blend it with agarose to obtain an eco-friendly material with desirable properties suitable for banana preservation. The PPMP exhibits a high methyl esterification degree (66.79%) and yield (29.83%) under optimal conditions consisting of a dry peel powder particle size of 0.25 mm, a mesocarp powder-to-citric acid solution ratio of 1 : 25 (g mL⁻¹), extraction at 90 °C for 60 min, followed by precipitation with 96% ethanol. To overcome the hydrophilicity and limited mechanical strength of neat PPMP films, agarose (A) is blended at varying concentrations of 0.5%, 1%, and 1.5% (w/v). Among the tested formulations, PPMP-A1.5 exhibited the best overall performance, exhibiting increased tensile strength (from 1.15 MPa for neat PPMP to 1.71 MPa), enhanced oxygen-barrier performance (OP reduced from 32.93 × 10⁻¹² to 21.60 × 10⁻¹² mol m⁻¹ s⁻¹ Pa⁻¹), and improved surface hydrophobicity (contact angle increased from 26.1° to 77.2°), despite certain trade-offs in flexibility and water vapor permeability. Preservation tests further confirm that the PPMP-A1.5 coating effectively prolonged the shelf life of bananas by up to 8 days at 25 °C, minimizing changes in peel browning, firmness, ripening rate, and pH. Notably, the weight loss of bananas coated with PPMP-A1.5 on day 6 is 11.69%, which is significantly lower than that of the uncoated samples (18.04%). These findings underscore the potential of PPMP/agarose coatings as safe, biodegradable, and sustainable packaging materials, serving as an alternative to conventional plastics and aligning with the principles of the circular economy.