**5. Conclusions and Outlook**

In summary, chitosan has good biological activities, including antibacterial and antioxidant activity and enzyme activity inhibition, and has demonstrated great potential in the field of food preservation. Thus, it has attracted widespread attention. Although there are inconsistent views among domestic and foreign scholars on the mechanism behind chitosan's preservation of food, the generally accepted views are as follows: (1) inter-charge interaction, (2) chelation of metal ions, (3) disruption of cell membranes to enter bacteria, bind DNA, and affect protein expression, (4) dense intramolecular hydrogen bonding of chitosan, and (5) binding to enzymes or structural proteins, which affects enzyme activity. In addition, chitosan preservation methods are constantly changing and will continue to be integrated.

This review is a discussion and summary of the current status of chitosan in the field of food preservation, to help the reader understand its importance as a sustainable material in this field and related strategies to improve its properties to enlighten future developments. While much work has been done to establish methods and elucidate the positive performance of chitosan in food preservation, there are still many difficulties and theoretical shortcomings in practical application. Therefore, future developments should focus on the following aspects: in-depth research on the mechanism behind chitosan's food preservation properties, and technical optimization and enrichment of strategies to further approach practical applications. In addition, studies analyzing the synergistic effects between components and methods as well as potential toxicity are also needed. Finally, the advantages of various technologies and composite components should be summarized regularly to help achieve effective the targeted inhibition of food spoilage sources. The future of chitosan as a sustainable material in the food preservation industry is bright, and expanding its application will be an inevitable trend as the technology continues to be developed.

**Author Contributions:** T.L. performed the conceptual design and supervised the work. J.L. was responsible for writing—original manuscript. Q.T. is responsible for data collection and literature search. P.Q. and D.G. were responsible for the article review. Project management and funding acquisition were handled by J.Z. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was funded by the Science and Technology Research Project of the Jilin Provincial Education Department (JJKH20210618KJ) and the Science and Technology Program of the Jilin Provincial Science and Technology Department (20210203135SF).

**Acknowledgments:** We thank the Science and Technology Research Project of Jilin Provincial Department of Education and the Science and Technology Program of Jilin Provincial Department of Science and Technology for financial support, and the laboratory of Changchun University College of Food for technical support.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

#### **References**

