In this work, polydopamine (PDA) was used to coat the carvacrol-loaded zein nanoparticles. The effect of the amount of PDA on the resulting antimicrobial activity antioxidant activity, and stability of the nanoparticles were studied. The topic is of interest, however, this work needs to be upgraded. Some suggestions are:
1. page 11, line 231, please change “05 mg/mL”as”0.5 mg/mL”.
2. page 11, line 249, The logic of this sentence “In other words, all of the PDA-coated nanoparticles (CLZPNPs) had a negative surface charge more than CLZNPs, which showed that the PDA-coating also increased the particle colloidal stability” is wrong.
3. page 12, line 253, “This increase could be explained by deprotonation of catechol –OH groups on the PDA shells (Liu, Cao, et al., 2013).” Please indicate whether “This increase” stands for “the increase of stability ” or “the increase of hydrophilicity ”.
4. page 12, line 254, “Another explanation for the increased stability could be done was based on the protein adsorption on the NPs (Lesniak et al., 2012; Liu, Huang, et al., 2013) by functionalization of the PDA shell to increase the stability of nanoparticle (Black et al., 2013; Ju et al., 2011).” Please describe the process of functionalization of PDA.
5. page 12, line 257, “Accordingly, excellent stability of PDA to provide stable surface properties was already reported (Liu, Cao, et al., 2013).” The grammar of this sentence is wrong.
6. page 12, line 258, “On the other hand, this stability effect of PDA was not concentration-dependent; in other words, the zeta potential did not change with the concentration of PDA.” The logic of this sentence is wrong.
7. page 12, line 265, “embed” was not used properly.
8. page 12,line 265, what does “these results”stand for? And “comparable” shouid be changed as “compared”.
9. CLZNPs and CLZPNPs have very little change in charge, the little change of the charge can not prove that the addition of PDA increases the stability of the system. More experiments should be done to prove that PDA increases the stability of the system, For example, the experiments of pH and temperature stability. In addition,more characteristics should be added, such as TGA or DSC.
10. page 13, line 282, “The peaks observed at 1649 and 1535 cm-1 in ZNPs and 1650 and 1540 cm-1 in CLZNPs showed revealed an electrostatic interaction between zein and carvacrol (Dai et al., 2018; Keawchaoon & Yoksan, 2011; Wei et al., 2019).” The grammar of this sentence is wrong, what is the subject of this sentence?
11. “The aforementioned O–H and N–H stretching that were revealed by the broad peaks in the range between 3500 and 3100 cm-1 in the spectra of ZNPs and CLZNPs (Fig. 2) could be attributed to capability to form inter molecular hydrogen bond, which leads an increased molecular cohesion (Pelissari et al., 2009).” The grammar of this sentence is wrong.
12. Please mark the peak position in Fig.2.
13. page 15, line 331, what is the “did nanoparticles” stand for?
14. ipage 15 ,line 333, please change “hydroxyl group(OH)” as “hydroxyl group(-OH)”.
15. Please quote these articles, such as :10.1016/j.molliq.2021.115586; . 10.1016/j.ijbiomac.2020.12.086; 10.1016/j.ijbiomac.2020.10.046.

accept