Microencapsulation of Gallic Acid Based on a Polymeric and pH-Sensitive Matrix of Pectin/Alginate

Round 1

Reviewer 1 Report

The text has several deficiencies in English writing. Some figures need a better explanation in the text. The SEM micrographs have very poor quality. Please see attached revised PDF of the manuscript with annotations and highlighted text that needs rephrasing/corrections.

Additional comments:

1. What is the main question addressed by the research?
- Encapsulation of gallic acid (GA) using pecti/alginate as the polymer shell by spray drying technique, in order to create a hermetic reservoir for the compound and inhibit its degradation by environmental conditions.

2. Do you consider the topic original or relevant in the field? Does it address a specific gap in the field?
- There are already more than 40 publications on the encapsulation of
There are not many studies on the encapsulation of GA:
https://www.webofscience.com/wos/woscc/summary/8c3f2103-4468-42fe-95d8-4caa77450b1d-9437cb47/relevance/1
However, there are only 3 publications regarding GA encapsulated in alginate polymers, hence it is relevant.
https://www.webofscience.com/wos/woscc/summary/60ef274c-7ca0-4d6e-ae0c-0964c6b210e0-9437e79d/relevance/1

3. What does it add to the subject area compared with other published material?
- Using pecti/alginate as polymer material for the microcapsules.

4. What specific improvements should the authors consider regarding the methodology? What further controls should be considered?
- The methodology is sound and correct.

5. Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed?
- Yes, but need to be rewritten in some cases due to poor English.

Comments for author File: Comments.pdf

The text has several deficiencies in English writing. Some figures need a better explanation in the text. The SEM micrographs have very poor quality. Please see attached revised PDF of the manuscript with annotations na highlighted text that needs rephrasing/corrections.

Author Response

RESPONSES TO THE REVIEWER’S COMMENTS

 

Ref.:  Ms. No. polymers-2471946

manuscript Title: Microencapsulation of gallic acid based on a polymeric and

pH-sensitive matrix of pectin/alginate

 

Dear Editor and reviewer

 

Please find below the detailed responses to the Reviewer’s/Editor’s comments. All changes/corrections made have been highlighted with a GREEN background in color. We have also enclosed the thoroughly revised version of the manuscript mentioned above according to the Reviewer’s comments, suggestions, and recommendations.

 

 

Reviewer 1.

 

The text has several deficiencies in English writing. Some figures need a better explanation in the text. The SEM micrographs have very poor quality. Please see attached revised PDF of the manuscript with annotations and highlighted text that needs rephrasing/corrections.

Author's response: Thank you very much for your observations and suggestions. The pdf was revised, and we have done the corrections. The English writing was revised by a native speaker accordingly, and SEM micrographs were obtained again to improve the quality. Please see Figure 3.

 

 

Additional comments:

1. What is the main question addressed by the research?
   - Encapsulation of gallic acid (GA) using pectin/alginate as the polymer shell by spray drying technique, to create a hermetic reservoir for the compound and inhibit its degradation by environmental conditions.

Author´s Response: Thank you for your valuable recommendation to improve the Manuscript. The main proposal of the research was rewritten in the introduction section.

 

2. Do you consider the topic original or relevant in the field? Does it address a specific gap in the field?
   - There are already more than 40 publications on the encapsulation of
   There are not many studies on the encapsulation of GA:
   https://www.webofscience.com/wos/woscc/summary/8c3f2103-4468-42fe-95d8-4caa77450b1d-9437cb47/relevance/1
   However, there are only 3 publications regarding GA encapsulated in alginate polymers, hence it is relevant.
   https://www.webofscience.com/wos/woscc/summary/60ef274c-7ca0-4d6e-ae0c-0964c6b210e0-9437e79d/relevance/1

Author´s Response: Thank you for your comments, we are aware that there are similar works with gallic acid, but in encapsulation with pectin and alginate only for the gallic acid compound, there is no such study, only extracts or a mixture of bioactive that contain Gallic acid. In addition, by the spray drying methodology, advantages are in consideration.

 

3. What does it add to the subject area compared with other published material?
   - Using pectin/alginate as polymer material for the microcapsules.

Author´s Response: Thank you for putting this out. The combination of alginate and pectin to formulate is better than each other alone to protect bioactive compounds from environmental effects. It was discussed in section 3.3.

4. What specific improvements should the authors consider regarding the methodology? What further controls should be considered?
   - The methodology is sound and correct.

Author´s response: Thank you for your revision.

 

5. Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed?
   - Yes, but need to be rewritten in some cases due to poor English.

Author´s response: Thank you for your comment. The English language was revised by a native English speaker to improve all the typos and major errors in the language.

 

Reviewer 2 Report

Comments:

1.             The abstract should be reduced. Avoid the initial description of the drawbacks of GA. Abstract should report a concise summary of the work. The description of limits and the state of art should be reported in the introduction section.

2.             There are many errors and typos. Editing of English language should be carried out.

3.             Introduction needs to be strengthened by reporting the novelty of the work, and the comparison with similar systems. Which are the added values? Only the combination of pectin and alginate?

4.             For each substance report the cas number, the purity and all the details.

5.             Use the same label formatting (ticks, legends, scale) for all graphs.

6.             Sem images are blurry, and the diameter distribution seems to not be unimodal. Moreover, the data of PSD don’t seem to be coherent with Sem images.

7.             Release kinetics: the profiles must start for t=0h. The curves should attain a plateau regime.

8.             The effect of pH on protonation or deprotonation of specific compounds should be stressed and better discussed. The effect of H+ concentration, swelling phenomena, surface erosion and mass transfer resistance of polymeric network should be considered.

9.             Which could be the potential application of these systems?

10.            How does this system appear to be better compared to a typical crosslinked systems? A comparison with crosslinked system (with CaCl2 for example) should be reported and discussed. 

Extensive editing of English language required

Author Response

 

RESPONSES TO THE REVIEWER’S COMMENTS

 Ref.:  Ms. No. polymers-2471946

manuscript Title: Microencapsulation of gallic acid based on a polymeric and pH-sensitive matrix of pectin/alginate

 

Dear Editor and reviewer

 Please find below the detailed responses to the Reviewer’s/Editor’s comments. All changes/corrections made have been highlighted with a GREEN background in color. We have also enclosed the thoroughly revised version of the manuscript mentioned above according to the Reviewer’s comments, suggestions, and recommendations.

 

Reviewer 2.

 

1. The abstract should be reduced. Avoid the initial description of the drawbacks of GA. The abstract should report a concise summary of the work. The description of limits and the state of the art should be reported in the introduction section.

Author´s Response: Thank the reviewer for your comments. We have addressed and reconstructed the abstract.

2. There are many errors and typos. Editing of the English language should be carried out.

Author´s Response: Thank the reviewer for the comment. The English language was reviewed by a professional native language speaker.

3. The introduction needs to be strengthened by reporting the novelty of the work, and the comparison with similar systems. Which are the added values? Only the combination of pectin and alginate?

Author´s Response: Thank the reviewer for your observation. The introduction was improved according to your comments.

 

4. For each substance report the CAS number, the purity, and all the details.

 Author´s Response: Thank the reviewer for the comment. The details were added accordingly

 

5. Use the same label formatting (ticks, legends, scale) for all graphs.

Author´s Response: Thank the reviewer for the comment. SEM experiments were performed again to improve the quality of the micrographs, considering the same scale and magnification (Please see Figure 3). Besides, the letter type was homogenized.

6. Sem images are blurry, and the diameter distribution seems to not be unimodal. Moreover, the data of PSD don’t seem to be coherent with Sem images.

Author´s Response: Thank the reviewer for the comment. Improved micrographs were obtained. They were correlated with the PSD experiments. Even with the monomodal distributions obtained, the PDI values are high. This indicates that the distribution size is broad and tends to cumulate as was appreciated in SEM micrographs. Please see Figures 2 and 3.  

7. Release kinetics: the profiles must start for t=0h. The curves should attain a plateau regime.

Author´s Response: Thank the reviewer for the comment. The graphs were modified. The present version shows an extended range from the origin in time zero. Please see Figure 5.

8. The effect of pH on the protonation or deprotonation of specific compounds should be stressed and better discussed. The effect of H+ concentration, swelling phenomena, surface erosion, and mass transfer resistance of the polymeric network should be considered.

Author´s Response: Thank the reviewer for the comment. The discussion was added in section 3.3

9. Which could be the potential application of these systems?

Author´s Response: Thank the reviewer for the comment. We included several reports focused on potential applications in section 3.3.

10. How does this system appear to be better compared to typical crosslinked systems? A comparison with crosslinked system (with CaCl2 for example) should be reported and discussed. 

Author´s Response: Thank the reviewer for the comment. In the formulation used in this paper, crosslinking agents were not used. It was previously established that the formation of hydrogen bonds between the methoxyl and the hydroxyl groups of pectin and alginate respectively, promotes the obtention of stable structures. Besides, the delivery of active compounds is strongly influenced by the pH of the solvent. This information was added in section 3.3.

 

Extensive editing of the English language required

 

Author´s Response: Thank the reviewer for the comment. The English language was reviewed by a professional native language speaker.

 

Reviewer 3 Report

The present work is well-organized, clear and straightforward. It mertis publication.

Tvo minor remarks:

1) Concerning DLS data. The size distribution could be given as supplementary materials.

2) What about zeta-potential. As far as I know, the DLS instrument used permits zeta-potential determination. It would be an interseting information, especially as a function of pH.

Author Response

 

RESPONSES TO THE REVIEWER’S COMMENTS

Ref.:  Ms. No. polymers-2471946

manuscript Title: Microencapsulation of gallic acid based on a polymeric and pH-sensitive matrix of pectin/alginate

 

Dear Editor and reviewer

Please find below the detailed responses to the Reviewer’s/Editor’s comments. All changes/corrections made have been highlighted with a GREEN background in color. We have also enclosed the thoroughly revised version of the manuscript mentioned above according to the Reviewer’s comments, suggestions, and recommendations.

Reviewer 3.

 

The present work is well-organized, clear, and straightforward. It merits publication.

Two minor remarks:

• Concerning DLS data. The size distribution could be given as supplementary materials.

 

Author´s Response: Thank the reviewer for the comment. The information was added to the manuscript in Figure 2.

 

• What about zeta potential? As far as I know, the DLS instrument used permits zeta-potential determination. It would be an interesting information, especially as a function of pH.

Author´s Response: Thank the reviewer for the comment. The data regarding zeta potential were added in Table 2.

Round 2

Reviewer 2 Report

The authors have provided with the required revisions. I can now recommend the publication.