Preparation and characterization of polyethylene-based composite films coated with carboxymethyl chitosan/sodium alginate/nisin and application in the packaging of Rosa roxburghii Tratt

Polyethylene (PE) films, as the mainstream packaging material for Rosa roxburghii Tratt, have weak preservation abilities leading to serious waste. In this study, PE films coated with carboxymethyl chitosan (CMCS), sodium alginate (SA), and nisin (CSN-PE) were prepared as novel packaging materials to extend the shelf life of Rosa roxburghii Tratt. CSN-PE films had excellent mechanical, optical, barrier, and thermal properties. When compared to PE films, CSN-PE films improved firmness, soluble solids, titratable acidity, ascorbic acid, total phenol, and antioxidant enzyme activities (superoxide dismutase and peroxides) and decreased decay rate and browning enzyme activity (polyphenol oxidase) during storage (1 ± 0.5 ℃ for 70 d). The shelf life models for R. roxburghii Tratt were established based on ascorbic acid content. Our results emphasized the practicability of CSN-PE films, and we concluded that CSN-PE films can significantly extend the freshness period of R. roxburghii Tratt by 28 days.