Bioactive coatings from nano-biopolymers/plant extract composites for complete protection from mycotoxigenic fungi in dates

BACKGROUNDContamination of date fruit with mycotoxigenic fungi is a hazardous threat. The present study investigated the effectiveness of natural derivatives for controlling this. Chitosan (Cts) was produced from Aspergillus niger mycelia and characterized and then nanochitosan (NCt) particles were synthesized from fungal Cts. Edible-coating films were formulated based on Cts, NCt, pomegranate peel extract (PPE) and their composites and these were evaluated as antifungal materials against mycotoxigenic fungi, Aspergillus flavus, Aspergillus ochraceus and Fusarium moniliforme. RESULTSThe Cts produced had 88.7% deacetylation, a molecular weight of 24.5kDa and 98% solubility in diluted acetic acid, whereas the particle diameters of synthesized NCts ranged from 35 to 65nm. The inhibition zone assay emphasized the antifungal effectiveness of the entire coating films. The most effective agent for preparing edible film was the blend of NCt+PPE followed by Cts+PPE based films. The practical application of antifungal films for date decontamination with respect to mycotoxigenic fungi demonstrates that the films were very effective for controlling the entire fungal strain and preventing growth on the fruits. CONCLUSIONThe NCt+PPE and Cts+PPE based films were found to be the most effective because they could completely eliminate the growth of any fungal spore on date fruit after 48h from the coating experiment. (c) 2019 Society of Chemical Industry