Sodium Alginate–Montmorillonite Composite Film Coatings for Strawberry Preservation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript entitled “Sodium Alginate/Montmorillonite Composite Film Coatings for Strawberry Preservation” combines experimental results from characterizations of composite film with strawberry preservation. With such comprehensive characterizations from 10 techniques, the work is beneficial for both academic and industrial sectors. The introduction and methodology sections are well written. The manuscript is also well prepared, and figures are properly presented. I therefore suggest only revision on the discussion part.

1) While large standard deviations in tensile strength and elongation at break are typical, the authors should explain error bars in Figure 2. They are inconsistent but mostly large, affecting the exist discussion on the permeability of composite film.  

2)  In Section 3.2, the discussion on strawberry preservation is not sufficiently cited. The discussion relies on only a few references and some long non-trivial explanations go without any citation. 

3) The results from 10 characterization techniques are mostly discussed separately. If the discussion section could not be more holistic, the authors should revise the conclusion.

4) The manuscript is well written, but the authors should keep the consistency (e.g. T_s not Ts and °C not oC).

Author Response

1) While large standard deviations in tensile strength and elongation at break are typical, the authors should explain error bars in Figure 2. They are inconsistent but mostly large, affecting the exist discussion on the permeability of composite film.  

Thanks for your suggestion. The reason for the large error value is that the sample used for the film comprises three horizontal and three vertical data, which is related to the process of making the film. As a rule of thumb, this range of differences is acceptable.

2) In Section 3.2, the discussion on strawberry preservation is not sufficiently cited. The discussion relies on only a few references and some long non-trivial explanations go without any citation. 

I have added some citations after the discussion.

3) The results from 10 characterization techniques are mostly discussed separately. If the discussion section could not be more holistic, the authors should revise the conclusion.

All of the techniques for characterizing the quality of the strawberry coatings are discussed; I think they can be combined. I have divided the conclusion into two paragraphs.

4) The manuscript is well written, but the authors should keep the consistency (e.g. Ts not Ts and °C not ^oC).

I have checked the manuscript for consistency.

 

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript concerns the preparation of sodium alginate (SA) and montmorillonite (MMT) composite films with SA and MMT as the matrix and glycerol as a plasticizer for use as a coating for strawberry preservation.  This manuscript is well written; the necessary data are appropriately included. However, the points written below must be taken into consideration.

1.     The correctness of Equation 2 should be checked.

2.     The results obtained in this study should be compared with the results obtained from similar studies in the literature and the differences of this study from those in the literature should be discussed. 

3.     A mechanism that explains the preparation and operation of the sodium alginate and montmorillonite composite films as a coating for strawberry preservation should be proposed.

Author Response

1. The correctness of Equation 2 should be checked.

I have checked and revised the equation.

2. The results obtained in this study should be compared with the results obtained from similar studies in the literature and the differences of this study from those in the literature should be discussed.

I think the results of fresh strawberry quality are different, not to mention the different packaging. I also searched for “strawberry, coating, and alginate” on Web of Science, which resulted in 63 articles. However, the film components are largely different, so I think it is unnecessary to discuss these results.

3. A mechanism that explains the preparation and operation of the sodium alginate and montmorillonite composite films as a coating for strawberry preservation should be proposed.

Yes, it is a very wide-ranging subject. I only want to apply the different recycled films or film solutions to package the fruit. Some of the mechanisms have also been described in the discussion section.

 

Reviewer 3 Report

Comments and Suggestions for Authors

In this study, sodium alginate (SA) and montmorillonite (MMT) composite films were prepared with SA and MMT as the matrix and glycerol as a plasticizer for use as a coating for strawberry preservation. The authors performed an extensive experimental work including mechanical properties, permeability, etc and the whole work is interesting.

POINTS FOR IMPROVEMENT.

1. The biostatic properties of the film was not studied. Is the film resistant to bacteria such as E. coli? or we have to add a compound?

2. Please, report the providers of the reagents along with some technical data (purity, MW of SA, etc)

3. Please, provide chemical type of MMT and SA

4. Please, compare your data with other scientists data in the area.

5. What's the thickness of the film?

6. What's the relation of this work to the current status of regulations for food packaging? A detailed review was given by Thapliyal, D et al Current Status of Sustainable Food Packaging Regulations: Global Perspective. Sustainability 2024, 16, 5554. https://doi.org/10.3390/su16135554

Author Response

1. The biostatic properties of the film was not studied. Is the film resistant to bacteria such as E. coli? or we have to add a compound?

This would be a good idea! However, the alginate-based film has many biostatic properties, as do its binary and ternary films. I will perform the experiment concerning different ratios of MMT and their effect on the antibacterial resistance of the composite film. This will be a significant amount of work.

2. Please, report the providers of the reagents along with some technical data (purity, MW of SA, etc)

I have added this information.

3. Please, provide chemical type of MMT and SA.

I have added this information.

4. Please, compare your data with other scientists data in the area.

I think the results of fresh strawberry quality are different, not to mention the different packaging. I also searched for “strawberry, coating, and alginate” on the Web of Science, which resulted in 63 articles. However, the film components are largely different, so I think it is unnecessary to discuss these results.

5. What's the thickness of the film?

The film is one-dimensional in three dimensions, which is a parameter for detecting the other properties of the film.

6. What's the relation of this work to the current status of regulations for food packaging? A detailed review was given by Thapliyal, D et al Current Status of Sustainable Food Packaging Regulations: Global Sustainability 2024, 16, 5554. https://doi.org/10.3390/su16135554

Yes, I have read the article on the rules of different countries. The films’ components, such as MMT, SA, and glycerol, are all eco-friendly and meet food-quality and contact-material requirements.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I have read the revised manuscript (coatings-3222643-peer-review-v2) with the title "Sodium Alginate–Montmorillonite Composite Film Coatings for Strawberry Preservation". The authors have not given the response and not made necessary corrections based on the reviewers’ comments.    If the referees’ questions are unnecessary, then why does the journal request peer review? It can publish directly without review. If the peer review is important for the journal, these questions should be answered and the manuscript should be revised according to the questions. If the peer review is not important for the journal, it can be published without answering the questions. The questions that still await answers are below.   2.         The results obtained in this study should be compared with the results obtained from similar studies in the literature and the differences of this study from those in the literature should be discussed.   3. A mechanism that explains the preparation and operation of the sodium alginate and montmorillonite composite films as a coating for strawberry preservation should be proposed.

Author Response

What the experts saying makes sense. Research should be done thoroughly. As a coating and packaging used for fruit and vegetable preservation, its principle of action is the selective permeability of gases and the isolation or inhibition of microorganisms, which are reflected in various tests. I think this mechanism is obvious. The strength of isolation performance involves too many factors, such as the molecular weight distribution of polymers in packaging materials, formulation, process, etc. And the purpose of this article is application. Personally, I believe that the mechanism of packaging should detect various factors in the death of the packaged goods. From my detection of factors in the decay process of fruits and vegetables, I can find that it is very complex. As for the comparison with similar articles, there are references in the analysis of various factors, and the overall process is similar, so there is no need to focus on it.

I think my published articles can illustrate the problem very well (For mechanism: https://doi.org/10.1016/j.colsurfb.2023.113272; For preservation: https://doi.org/10.1016/j.ijbiomac.2019.09.035 ).

Reviewer 3 Report

Comments and Suggestions for Authors

ACCEPTED!

Author Response

Thank you!