Abstract:

In order to invent a safe and efficient composite film for the preservation of strawberry, which could extend the shelf life, nitrogen-doped carbon quantum dots were prepared by hydrothermal method using bitter bamboo shoots hull as raw material. The prepared nitrogen-doped carbon quantum dots were used as bacterial inhibitor, to produce a composite film with chitosan as the film-forming material. The inhibition effects of the mass fraction of nitrogen-doped carbon quantum dots in the composite film against Escherichia coli and Staphylococcus aureus were investigated as well as the effect on quality indexes during the storage of strawberry. It was shown that the prepared nitrogen-doped carbon quantum dots had photocatalytic inhibition effect, and the inhibition effect against E. coli and S. aureus increased with the increase of mass fraction of nitrogen-doped carbon quantum dots in the composite film. The nitrogen-doped carbon quantum dots-chitosan composite film showed good preservation effects on strawberry, as it could reduce the weight loss and decay rate of strawberry, and delay the consumption and transformation of nutrients such as soluble solids and ascorbic acid in fruits. When the mass fraction of nitrogen-doped carbon quantum dots in the composite film was 5%, its preservation effect was the best under the experiment conditions.

Key words: carbon quantum dots, chitosan, strawberry, composite film, preservation