Tropical fruits, predominantly cultivated in Southeast Asia, are esteemed for their nutritional richness, distinctive taste, aroma, and visual appeal when consumed fresh. However, postharvest challenges have led to substantial global wastage, nearly 50 %. The advent of edible biopolymeric nanoparticles presents a novel solution to preserve the fruits' overall freshness. These nanoparticles, being edible, readily available, biodegradable, antimicrobial, antioxidant, Generally Recognized As Safe (GRAS), and non-toxic, are commonly prepared via ionic gelation owing to the method's physical crosslinking, simplicity, and affordability. The resulting biopolymeric nanoparticles, with or without additives, can be employed in basic formulations or as composite blends with other materials. This study aims to review the capabilities of biopolymeric nanoparticles in enhancing the physical and sensory aspects of tropical fruits, inhibiting microbial growth, and prolonging shelf life. Material selection for formulation is crucial, considering coating materials, the fruit's epidermal properties, internal and external factors. A variety of application techniques are covered such as spraying, and layer-by-layer among others, including their advantages, and disadvantages. Finally, the study addresses safety measures, legislation, current challenges, and industrial perspectives concerning fruit edible coating films.
This study developed a chitosan-alginate edible bio-nanocomposite (EBNC) coating, reinforced with a cellulose nanocrystal (CNC)-stabilized ginger essential oil (GEO) Pickering emulsion, for postharvest preservation of papaya (Carica papaya L.). The EBNC showed a particle size of 825.32 ± 35.58 nm (PDI 0.491) and a zeta potential of -34.2 ± 3.63 mV, while FTIR and DSC indicated extensive hydrogen bonding and thermal stability. Microscopy revealed a hybrid isotropic-anisotropic microstructure, in which CNC-induced anisotropic domains are proposed to increase diffusion tortuosity and thereby improve barrier performance. Cytocompatibility was concentration- and time-dependent, with >80% NIH-3T3 viability at ≤250 μg/mL after 48 h. On papaya stored under ambient conditions, the coating significantly reduced weight loss (p 1000 μg/mL), and fungal regrowth after subculture indicated a predominantly fungistatic effect. Mechanistic assays showed membrane permeabilization (PI uptake 44.58 ± 9.67%), nucleic acid leakage (51.02 ± 8.67%), and limited ergosterol inhibition (10.83%), identifying the membrane, rather than ergosterol biosynthesis, as the principal target. Overall, the EBNC combines barrier-related quality preservation with moderate fungistatic activity, offering a promising postharvest strategy for papaya. However, the findings are limited to ambient storage and in vitro antifungal assays; in vivo disease challenge, sensory acceptability, and food-safety assessment remain to be established.