**4. Conclusions**

In this study, caseinate-stabilized thymol nanosuspensions were successfully fabricated via the pH-driven method. Thymol were extremely stable at pH 7.0–12.0 even after incubation for 24 h, which means the loss of thymol during the pH-driven process is negligible. The physchemical properties of thymol nanosuspensions are highly dependent on the caseinate concentration. Caseinate could stabilize thymol nanosuspensions even at a relatively low caseinate concentration, and the loading capacity can be as high as 45.9%. AFM and TEM results showed that the nanosuspensions were uniformly distributed. The thymol nanosuspensions remained stable under high temperature and long-time storage at room temperature. The antimicrobial activity of thymol nanosuspensions was lower than free thymol, which could be due to the bonding between caseinate with thymol and thus retard its release and antimicrobial effects. This work and these results may provide useful information for the design of functional food, cosmetics, and pharmaceutical productions using the pH-driven method.

**Author Contributions:** W.Z.: Conceptualization, Investigation, Data Curation, Writing—Original Draft. Y.Z.: Investigation. R.L.: Formal analysis, Visualization. S.P.: Validation, Funding acquisition, Methodology, Writing—Review & Editing. R.R.: Writing—Review & Editing, Supervision. J.L.: Supervision, Project administration. W.L.: Supervision, Project administration. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the China Postdoctoral Science Foundation (2020M682111), "Shuangqian Project" of Scientific and Technological Innovation of High-end Talents-Natural Science, Jiangxi Province (S2019GDKX2836), the State Key Laboratory of Food Science and Technology of Nanchang University (No. SKLF-KF-2020015), the Natural Science Foundation of Guangdong Province of China (grant number 2021A1515010901), the Natural Science Foundation of Hainan Province of China (grant number 320QN325), the Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences (grant number 1630122017016 and 1630122021006), and the 'Guangdong Special Support Plan' Science and Technology Innovation Young Talents Project (2019TQ05N133).

**Acknowledgments:** All authors are thankful to their representative universities/institutes for the support and services used in this study.

**Conflicts of Interest:** The authors declare no conflict of interest.
