Application of Glycine betaine coated chitosan nanoparticles alleviate chilling injury and maintain quality of plum (Prunus domestica L.) fruit

The use of edible coatings can lead to significant extension of the postharvest life of fresh horticultural products through the regulation of water and gaseous exchange during storage. In this regard, nano-engineered materials are of great interest to design novel and multifunctional edible coatings and are increasingly employed. Chitosan and glycine betaine have been reported to enhance fruit tolerance to chilling stress during cold storage. The current study applied new coating treatments to plum (Prunus domestica L. cv. ‘Stanley’) fruit at maturity stage in a completely randomized factorial design with three replicates. Plums were treated with distilled water (control), glycine betaine (GB) at 2.5 and 5 mM, chitosan (CTS) at 1% (w/v) or glycine betaine-coated chitosan nanoparticles (CTS-GB NPs) at 0.5 and 1% (w/v) and stored at 1 °C for up to 40 days. The application of CTS-GB NPs (0.5% w/v) was the most effective treatment and induced lower electrolyte leakage, MDA and H2O2 content, and significantly alleviated chilling injury. Furthermore, this treatment remarkably increased the activity of PAL enzyme, resulting in higher levels of phenolics, flavonoids and anthocyanins content, and enhanced DPPH scavenging capacity. In addition, CTS-GB NPs treatment increased endogenous GB (9.25 mg g−1 DW) and proline (1929.29 μg g−1 FW) accumulation leading to higher activity of CAT, POD, SOD and APX enzymes. Based on the obtained results, the commercial application of CTS-GB NPs could effectively reduce chilling injury, preserve nutritional quality, and prolong the storage potential and shelf life of plum fruit. •The glycine betaine coated chitosan nanoparticles (CTS-GB NPs) was synthesized successfully.•CTS-GB NPs nanoparticles not only reduced chilling injury but also improved quality attributes of plum fruit•Application of CTS-GB NPs could be effective in preserving the nutritional quality and prolonging the shelf life of plum fruit