# Preparation and Characterization of D-Carvone-Doped Chitosan–Gelatin Bifunctional (Antioxidant and Antibacterial Properties) Film and Its Application in Xinjiang Ramen

## TL;DR

This study creates a food packaging film with antioxidant and antibacterial properties using chitosan, gelatin, and D-carvone, showing improved performance for preserving Xinjiang ramen.

## Contribution

The paper introduces a bifunctional film with optimized D-carvone content for food preservation, balancing mechanical and sensory properties.

## Key findings

- Adding 1% D-carvone improved mechanical and barrier properties of the film.
- D-carvone at 1–2% enhanced antioxidant and antibacterial activity significantly.
- Excessive D-carvone (over 2%) degraded film quality and sensory attributes of the noodles.

## Abstract

In this study, a composite film with dual antioxidant and antibacterial properties was prepared by combining 2% chitosan and 7% gelatin (2:1, w:w), with D-carvone (0–4%) as the primary active component. The effect of D-carvone content on the performance of the composite films was systematically investigated. The results showed that adding 1% D-carvone increased the water contact angle by 28%, increased the elongation at break by 35%, and decreased the WVTR by 18%. FTIR and SEM confirmed that ≤2% D-carvone uniformly bonded with the substrate through hydrogen bonds, and the film was dense and non-porous. In addition, the DPPH scavenging rate of the 1–2% D-carvone composite film increased to about 30–40%, and the ABTS+ scavenging rate increased to about 35–40%; the antibacterial effect on Escherichia coli and Staphylococcus aureus increased by more than 70%. However, when the addition amount was too high (exceeding 2%), the composite film became agglomerated, microporous, and phase-separated, affecting the film performance, and due to its own taste, it reduced the sensory quality of the noodles. Comprehensively, the composites showed better performance when the content of D-carvone was 1–2% and also the best effect for freshness preservation in Xinjiang ramen. This study provides a broad application prospect for natural terpene compound-based composite films in the field of high-moisture, multi-fat food preservation, and provides a theoretical basis and practical guidance for the development of efficient and safe food packaging materials. In the future, the composite film can be further optimized, and the effect of flavor can be further explored to meet the needs of different food preservation methods.