Physical-mechanical and antifungal properties of pectin nanocomposites / neem oil nanoemulsion for seed coating

Abstract

Biodegradable polymers, when reinforced with nanostructures, are considered good sustainable coatings and viable alternatives to replace conventional coatings. In addition, biopesticides are also considered safe, biodegradable and environmentally friendly; therefore there is a growing interest in nanoemulsions based on phytochemical mixtures. In this context, the aim of this study is to aggregate Neem oil nanoemulsions and pectin matrices to produce nanocomposite films, as well as evaluate the nanoemulsions effect on the film properties for coating soybean seeds. Nanoemulsions were characterized assessing their average diameter and stability, while the nanocomposite antifungal, morphology, mechanical and barrier properties were analyzed. In general, the nanoemulsions had an average diameter close to 59 ± 0.61 nm, showed good stability and its addition improved film mechanical properties: reduced stiffness, resistance, and water vapor permeability, and increased extensibility. In addition, Neem oil provided antifungal properties against Aspergillus Flavus and Penicillium Citrinum. The seed coatings promoted a positive effect on the germination process of soybean seeds. Thus, antifungal nanocomposite films from renewable sources were successfully produced. The fungicidal inhibition of Neem oil as a nanoemulsion makes these new materials promising for the production of seed coatings.