Green polymer film preservation material prolongs the shelf life of mangoes

The Laboratory of New Materials for Dry Crops of the South Asian Tropical Crops Research Institute of the Chinese Academy of Tropical Agricultural Sciences recently constructed a composite coating film preservation material by modifying chitosan and gellan gum, and studied the barrier properties, mechanical properties and antibacterial properties of composite materials
.
At the same time, the scientific research team applied the composite coating liquid to mango preservation, which solved the problem of poor mechanical properties and insufficient antibacterial performance of
single chitosan polymer coating film cling film.

Film preservation is one of the new preservation methods that have emerged in recent years, mainly using the coating liquid to form a thin polymer film on the surface of the fruit to inhibit the gas and water vapor exchange of fruits and vegetables and the metabolism of fruits and vegetables, thereby reducing the respiration intensity of harvest fruits, reducing water evaporation, and achieving the purpose
of extending the shelf life of fruits.
Green and efficient coating materials are the key to the development of
film preservatives.
Chitosan is one of the polysaccharides abundant in nature, with good biocompatibility, degradability, film-forming, barrier and antibacterial, and is considered to be one of the
ideal materials for edible film preservation.
However, chitosan membrane has problems such as
poor mechanical properties and insufficient bacteriostatic performance after filming.
Gellan gum is a natural microbial polysaccharide with high transparency, strong stability and other properties, and has been used in food, daily necessities, medicine and other fields
.
The introduction of gellan gum can effectively improve the mechanical properties
of chitosan after filming.
Plant essential oil is a kind of secondary metabolites of plant origin, with broad-spectrum and efficient antibacterial activity, which can not only effectively improve the antiseptic and antibacterial effect of the coating material, but also improve the mechanical properties of the coating film and produce synergistic effect
.
In this study, chitosan carboxymethyl was modified and added to a cholic acid group to form an amphiphilic chitosan derivative, which had good water solubility and better compatibility with hydrophobic materials, and then compounded with water-soluble carboxymethyl gellan glue to construct polymer film preservation materials
.

The results show that composite materials with plant essential oils can be applied to the development of food preservation packaging materials with high antibacterial activity, which provides a new way
for the development of green multi-functional fruit preservation materials.
After composite coating treatment, the peak respiration period of mango can be extended, and the shelf life
of mango can be extended.
Studies have also found that composite materials with mustard essential oil can delay fruit spoilage and aging, and prevent large changes
in fruit nutrients.

(Yang Ziming)

China Food News(November 29, 2022, Version 05)

(Responsible editor: Gao Jiaodi)