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Strawberries have a thin epidermis and a high respiration rate. The use of edible coatings containing chitosan nanoparticles (CSNPs) and propolis (P) has been effective in preserving the shelf life and antioxidant capacity of various fruit and vegetable products. The present research evaluated the effect of coatings with CSNPs and P on the quality, antioxidant compounds, and antioxidant capacity of strawberries. The specific coatings that were evaluated were chitosan (CS), CS+CSNPs33%, CS + CSNPs + P10%, CS + CSNPs + P20%, CS + CSNPs + P30%, and a control with no coating. The variables were weight loss, firmness, total soluble solids (TSS), color, phenols, total flavonoids, antioxidant capacity, and sensory characteristics. An ANOVA and a Tukey test (p ≤ 0.05) were used to analyze the data. Strawberries covered with CS + CSNPs + P10% showed the lowest weight loss (9.77%), while those covered with CS + CSNPs + P20% had the greatest firmness (4.96 N). CS + CSNPs + P coatings at 10%, 20%, and 30% concentrations maintained the antioxidant compounds and antioxidant capacity in the evaluated fruit (28.49 mg GAE g−1, 554.61 μg quercetin g−1, and 92.48% DPPH, respectively). The application of nanostructured coatings did not modify the sensory characteristics of the fruit. Coatings with CSNPs and/or P could therefore be a viable alternative for preserving the quality and antioxidant capacity of strawberries.

A great diversity of agricultural products is susceptible to contamination caused by Aspergillus flavus . To reduce fungal contamination, the application of natural products has been proposed, including chitosan and propolis, due to its broad and recognized antimicrobial activity on several microorganisms. Currently, the application of nanotechnology allows for a greater activity to be more reactive and efficient. The objectives of this research were to characterize by TEM and Z potential some of the studied nanoparticles and to determine the in vitro antifungal activity of the formulations and the production of aflatoxins of the treated fungus. For this, individual treatments and different nanoformulations were elaborated by varying the percentage of the components such as chitosan solution, chitosan nanoparticles, an extract of propolis, nanoparticles of propolis, glycerol and canola oil. The final concentrations of the formulations were of 20%, 30% and 40% and the control consisted of Czapeck-dox agar medium. TEM micrographies showed a spherical morphology in a range of 2.3–3.0 nm with values of Z potential from 18.5 to 116.2 nm. Compared to the untreated fungus, the highest effect was seen in the parameter of spore germination, since inhibition was of c. a. 97% corresponding to the formulation containing chitosan + propolis nanoparticles + chitosan nanoparticles + propolis extract at the highest concentration of 40%. At this same concentration, the production of aflatoxins was 100% inhibited with the treatment with chitosan at 1%. Since these results are under carefully controlled conditions, further research should be extended to different fruit and vegetables affected by this fungus.

Biodegradable alternatives for the control of Aspergillus flavus in fig fruit were tested with the application of coatings based on chitosan (CS) and propolis (P). To potentiate the fungicidal effect, nanoparticles of these two (CSNPs and PNPs) were also considered. The objectives of this research were to evaluate the effect of different formulations on: (a) the ripening process of the fig, (b) the incidence of A. flavus and the production of aflatoxins, and (c) the acceptance of the treated fruit by a panel. The nanostructured coatings did not influence the ripening process of the fruit during the 12 days of storage, however, the antioxidant activity increased by approximately 30% with the coating CS + PNPs + P. The figs treated with CS + CSNPs + PNPs + P, inhibited the growth of the fungus by about 20% to 30% under laboratory and semi-commercial conditions. For all treatments, the aflatoxin production was lower than 20 ppb compared to the control with values of c.a. 250 ppb. The sensory quality was acceptable among the panel. The edible coatings can be a non-toxic alternative for post-harvest preservation and the consumption of fig fruit. The next step will be its inclusion and evaluation at a commercial level in packing houses.