**4. Conclusions**

The hollow zein particles coated with chitosan and pectin were prepared with 1% Na2CO3 as a sacrificial template. The hollow particles coated with 1 mg/mL chitosan and 0.1 mg/mL pectin had a size of 219 nm and ζ-potential of −28 mV. Chitosan coating improved the loading efficiency of quercetin in hollow zein particles. The coating of chitosan/pectin improved the stability of quercetin-loaded hollow zein particles against heat treatment, pH variation and salt. The entrapment in the hollow particles improved the photostability and storage stability of quercetin. The storage stability was better at 25 ◦C for entrapped quercetin but at 45 ◦C for hollow zein particles coated with chitosan and pectin. These findings will extend the application of composite hollow zein particles for the incorporation of bioactive components in functional products.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/10 .3390/antiox10091476/s1, Figure S1: Size distribution (A) and ζ-potential (B) of hollow zein (HZ) particles coated with chitosan (HZ-chi) and with chitosan and pectin (HZ-chi/pec) without and with quercetin. Figure S2: Visual appearance of quercetin-loaded hollow zein particles (A) coated with chitosan (B) and with chitosan and pectin (C) at 50–500 mM NaCl. Figure S3: Visual appearance of qHZ, qHZ-chi, qHZ-chi/pec at 25 ◦C (A), 45 ◦C (B). Figure S4: Calibration curve of quercetin.

**Author Contributions:** M.A.K. and C.Z.; Conceptualization, Investigation, Writing—original draft preparation, Writing—review and editing, P.Z. and M.Z.; Writing—review and editing, L.L.; Writing review and editing, Reviewing, Supervision. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work received support from the National Natural Science Foundation of China (NSFC Project 31571781).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available in this manuscript.

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