Extension of the postharvest quality of bell pepper by applying nanostructured coatings of chitosan with Byrsonima crassifolia extract (L.) Kunth

The aim of this work was to evaluate the structure, chemical composition and biological activity of nanoparticles composed of chitosan (CNPs) and chitosan with Byrsonima crassifolia extract (CENPs), with which two EC, edible nanochitosan coatings (ENC) and edible nanochitosan extract coatings (ENEC) were elaborated, respectively. These coatings were sprayed on bell pepper during the pre-harvest stage and microbiological activity was determined. After harvesting the quality of bell pepper was evaluated for the following variables: weight loss, firmness, color change, respiration, ethylene production, total carotenoids, phenolic content, antioxidant capacity, and microbiological activity. The result indicated that the volatile fraction of Byrsonima crassifolia extract is 94% composed of a pinene, camphene, and eucalyptol. The CNPs had a higher size distribution 420 nm than the CENPs 312 nm and a potential Zeta of -40 mV. The CNPs and CENPs decreased the in vitro growth of Alternaria alternata up to 100%. During the cultivation of the fruit, both EC reduced the microbiological activity by 80%. In the postharvest stage some changes were observed in the fruit treated with the EC, for instance: 1) the fruit showed a 30% the weight loss and 15% the change of color after 21 d of storage, 2) the phenolic content, carotenoids and reducing capacity were increased by 18% and 3) the microbiological activity was reduced by 85%. In conclusion, the application of ENC and ENEC during the cultivation and postharvest storage of bell pepper preserved the physicochemical quality, improved microbiological quality and increased their antioxidant content.