Postharvest treatment of nanochitosan-based coating loaded with Zataria multiflora essential oil improves antioxidant activity and extends shelf-life of cucumber

Abstract

The effects of postharvest treatment with chitosan nanoparticles (CSNPs = T1) and Zataria multiflora essential oil (ZEO) incorporated in (ZEO@CSNPs = T2), on the shelf-life extension and antioxidant activities of whole cucumbers during storage were evaluated. Coated and control cucumbers were stored at 10 ± 1°C with 90-95% RH for 21 days. Measurements of physicochemical and microbial growth were accomplished every 3 days. After 15 days, the fruit decay in the T2 coating was 2% vs. 12 and 97.7% in the T1 coated and uncoated fruit, respectively. Significant differences were obtained for weight loss, firmness, respiration rate, DPPH-radical scavenging activity, reducing power and microbial counts (P < 0.05) during storage. There were significantly higher levels of DPPH-radical scavenging activity and reducing power in T2-treated cucumbers compared with that in the T1-treated followed by the control fruit. In conclusion the ZEO loaded CSNPs coating could improve the quality of cucumber and protect the bioactive components during storage. Industrial relevance: Cucumber as a good source of antioxidants is one of the most popular and widely grown vegetable crops in the world. However, it has a short shelf-life (< 14 days) that is mainly related to firmness loss, discoloration, desiccation and fungal rot. The reduction of losses is a major objective of postharvest technology for cucumbers, which tries to utilize safe and efficacious methods to control contamination and the growth of spoiling fungi. On the other hand, the nano-/micro-encapsulation of EOs allows protection of their sensitive bioactive compounds from unfavorable environmental conditions and enhances their bioactivity during food processing and storage. So, in this study a new edible coating, consisting of Zataria multiflora essential oil (ZEO) incorporated into chitosan nanoparticles (CSNPs), was introduced to extend the shelf-life of cucumber as well as protect the bioactive compounds with antioxidant properties.