Effect of Biodegradable Coatings on the Growth of Aspergillus flavus In Vitro, on Maize Grains, and on the Quality of Tortillas during Storage

The fungus Aspergillus flavus causes serious damage to maize grains and its by-products, such as tortilla. Currently, animal and plant derivatives, such as chitosan and propolis, and plant extract residues, respectively, are employed as alternatives of synthetic fungicides. The objective of this research was to evaluate the efficacy of several formulations based on propolis-chitosan-pine resin extract on the in vitro growth of A. flavus, the growth of maize grain plantlets and the quality of stored tortillas at 4 and 28 degrees C. The most outstanding formulation was that based on 59.7% chitosan + 20% propolis nanoparticles + 20% pine resin extract nanoparticles; since the in vitro conidia germination of A. flavus did not occur, disease incidence on grains was 25-30% and in tortillas, 0% infection was recorded, along with low aflatoxin production (1.0 ppb). The grain germination and seedling growth were markedly reduced by the nanocoating application. The percentage weight loss and color of tortillas were more affected by this coating compared to the control, and the rollability fell within the scale of non-ruptured at 4 degrees C and partially ruptured at 28 degrees C. The next step is to evaluate the toxicity of this formulation.

Automated summary

This study evaluated the effect of propolis-chitosan-pine resin extract formulations on the growth of Aspergillus flavus, maize plantlets, and stored tortillas. The most effective formulation inhibited conidia germination, reducing disease incidence and aflatoxin production. However, the nanocoating treatment had a negative impact on tortilla quality and appearance. Further toxicity evaluations are needed.