Ultrasonic Technique for Production of Nanoemulsions for Food Packaging Purposes: A Review Study

Round 1

Reviewer 1 Report

The review has been properly conducted, I would only suggest to reduce the length of the Introduction section (especially the overall introduction of packaging, that actually did not focused on use of EOs).

Additionally, I would also suggest to change the title: no information have been provided for use of NEs in food packaging, only use of NEs in food. Please, change the title accordingly.

Author Response

Dear Editor

On behalf of the authors, we highly appreciate the kindness of the scientific reviewers and their deep and thorough comments. We are satisfied with the correctness and improvements of our paper due to the comprehensive and wisely comments from the reviewers. We have revised the present research paper in the light of their useful suggestions and comments. I hope our revision has improved the paper to the level of their satisfaction and suitable for publication. Our answers to their specific comments, suggestion, queries are finned the following.

Best Regards

Changes in the manuscript are written in red color (color of the font and not highlighted).

Responses to Reviewer 1

First of all, I would like to warmly appreciate you for your time, and considerations on evaluation of our manuscript. No hesitate that your revision make our study more outstanding, and highly qualified, eligible for possible publication.

1. The review has been properly conducted, I would only suggest to reduce the length of the Introduction section (especially the overall introduction of packaging, that actually did not focused on use of EOs).

Response: As you requested, we shortened the introduction part from 959 words to 761 words with more cohesion and coherence, and without any major changes leading to loss of content in introduction section.

2. Additionally, I would also suggest to change the title: no information have been provided for use of NEs in food packaging, only use of NEs in food. Please, change the title accordingly.

Response: Alterations in the title were done and the final title is: “Ultrasonic Technique for Production of Nanoemulsions for Food Packaging Purposes: A Review Study”.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper presents a comprehensive study on the latest research in the field of obtaining of essential oils nanoemulsions and their utilisation in food packaging systems. The paper topic is according with the actual trends on identification of green solutions to obtain the food packaging with functional and appropriate characteristics for foods protection and preservation.

The paper is well structured with an appropriate list of references and in line with Coatings journal topics.

Comments

1. In the legend of figure 3, the explanations of images A and B must be described.
2. On page 14 the details in the brackets for PDI index must to be presented.
3. Section 3.3.1. I consider that the more details regarding the actual utilisation of essential oils nanoemulsions obtained by ultrasound technique in packaging systems are necessary; it is not very clear presented in the review the utilisation of the NEs in biopolymer films or/and composite coatings (for paper packing for example). In the Conclusions section it is emphasized that….…….. By emergence of nanotechnology based approaches, it has been demonstrated that incorporation of EOs based NEs (encapsulated forms of EOs in delivery systems with anti-bacterial, anti-fungal, and antioxidant properties) can sufficiently increase food compatibility, easy dispersion of EOs in growing regions of microorganisms, and give a long-lasting stability against gravitational forces, creaming, and sedimentation in EOs……

what are the delivery systems used for incorporation EOs based NEs?

Author Response

Dear Editor

On behalf of the authors, we highly appreciate the kindness of the scientific reviewers and their deep and thorough comments. We are satisfied with the correctness and improvements of our paper due to the comprehensive and wisely comments from the reviewers. We have revised the present research paper in the light of their useful suggestions and comments. I hope our revision has improved the paper to the level of their satisfaction and suitable for publication. Our answers to their specific comments, suggestion, queries are finned the following.

Best Regards

Changes in the manuscript are written in red color (color of the font and not highlighted).

Responses to Reviewer 2

The paper presents a comprehensive study on the latest research in the field of obtaining of essential oils nanoemulsions and their utilisation in food packaging systems. The paper topic is according with the actual trends on identification of green solutions to obtain the food packaging with functional and appropriate characteristics for foods protection and preservation.

The paper is well structured with an appropriate list of references and in line with coatings journal topics.

First of all, I would like to warmly appreciate you for your time, and considerations on evaluation of our manuscript. It would be our privilege to promote content of your journal with our highly resourceful articles. No hesitate that your revision make our study more outstanding, and highly qualified, eligible for possible publication.

1. In the legend of figure 3, the explanations of images A and B must be described.

Response: As you requested, a brief explanation was added in the caption of figure.3 (page 8), and a more detailed statement was added to the explanations embedded in the manuscript (page 7).

“Figure 3. Anti-bacterial mechanisms of Origanum compactum EOs against Bacillus subtilis [65]. (A) Effects of Origanum compactum EOs against Bacillus subtilis through inhibition on quorum sensing. (B) Effects of Origanum compactum EOs against Bacillus subtilis through making a cytoplasmic material.”

1. On page 14 the details in the brackets for PDI index must to be presented.

Response: As you requested it was clarified on second paragraph of page 15 (It is corrected on page 15, due to after minor revisions and adding the pages, page 14 has been turned into page 15).

1. Section 3.3.1. I consider that the more details regarding the actual utilisation of essential oils nanoemulsions obtained by ultrasound technique in packaging systems are necessary; it is not very clear presented in the review the utilisation of the NEs in biopolymer films or/and composite coatings (for paper packing for example).

Response: thanks for your comment. Awe tried to cover all details related to EO-based Nanoemulsion obtained by ultrasound technique considering the size, stability, and antibacterial activity. We also tried to cover the operational parameters. More details was added in over this section.

It is necessary to say that, in the previous sections we mentioned this issue too regarding nanoemulsions. Section 3.3.1 basically focuses on Nanoemulsion production by ultrasonic and covering the details. Nanoemulsions are nanoemulsions and they can be produce by various techniques. We firstly tried to highlight the role of nanoemulsions and essential oils in food packaging (section 3.1 & 3.2). Then discussed the ultrasonic technology as a technique to produce nanoemulsions.

1. In the Conclusions section it is emphasized that….…….. By emergence of nanotechnology based approaches, it has been demonstrated that incorporation of EOs based NEs (encapsulated forms of EOs in delivery systems with anti-bacterial, anti-fungal, and antioxidant properties) can sufficiently increase food compatibility, easy dispersion of EOs in growing regions of microorganisms, and give a long-lasting stability against gravitational forces, creaming, and sedimentation in EOs. What are the delivery systems used for incorporation EOs based NEs?

Thanks for the comment. Actually we meant diffusion by delivery systems. It was just a wrong choice which the sentence has been corrected. In the case of food packaging, Nanoemulsion are embedded within the food packaging system to prevent microorganism growth. In this regard diffusion occurs.

Author Response File: Author Response.docx

Reviewer 3 Report

It has been a great honor, as well as a pleasantly challenging activity, to review the article entitled “Ultrasonic Techniques for Production of Nanoemulsions from Essential Oils for Food Packaging Purposes: A Review Study” by Anisa Jafari and Hamed Ahari.

The article is structured following the classic model for this type of material (Research Article), comprising four parts: Introduction, Search Method, Results and Discussion, and Conclusions. The four major components of the article are presented coherently and logically, tightly linked to one another.

Authors should check the list of references. In some cases, references to a statement do not apply to it.

I enclose the revised manuscript with my comments.

Comments for author File: Comments.pdf

Author Response

Dear Editor

On behalf of the authors, we highly appreciate the kindness of the scientific reviewers and their deep and thorough comments. We are satisfied with the correctness and improvements of our paper due to the comprehensive and wisely comments from the reviewers. We have revised the present research paper in the light of their useful suggestions and comments. I hope our revision has improved the paper to the level of their satisfaction and suitable for publication. Our answers to their specific comments, suggestion, queries are finned the following.

Best Regards

Changes in the manuscript are written in red color (color of the font and not highlighted).

Responses to Reviewer 3

It has been a great honor, as well as a pleasantly challenging activity, to review the article entitled “Ultrasonic Techniques for Production of Nanoemulsions from Essential Oils for Food Packaging Purposes: A Review Study” by Anisa Jafari and Hamed Ahari. The article is structured following the classic model for this type of material (Research Article), comprising four parts: Introduction, Search Method, Results and Discussion, and Conclusions. The four major components of the article are presented coherently and logically, tightly linked to one another.

First of all, I would like to warmly appreciate you for your time, and considerations on evaluation of our manuscript. It would be our privilege to promote content of your journal with our highly resourceful articles. No hesitate that your revision make our study more outstanding, and highly qualified, eligible for possible publication.

• Authors should check the list of references. In some cases, references to a statement do not apply to it.

Response: All of the references were checked.

I enclose the revised manuscript with my comments.

Comments:

• Please check this categorization of active packages. It is not unanimous neither applied. Consulting the references mentioned (11, 17 and 18) these is not valid. Please check.

Response: Thanks for your wise comment. That sentence has been removed. Considering the references, if understood your comment correctly the mentioned references were valid. Their links can be found below:

Ref 11: https://www.sciencedirect.com/science/article/pii/S1658077X16300765.

Ref 17: https://www.sciencedirect.com/science/article/abs/pii/S0963996918304356.

Ref 18: https://link.springer.com/article/10.1007/s12562-017-1090-4.

• What is chemical formulation of food? Please explain.

Response: it was just a wrong choice in explaining. It was corrected in the introduction. We actually meant “the nature of food”.

• Replace by "Results and Discussion".

Response: Requested changes were done in the heading.

• What these acronyms mean? Must put a legend of the table 1.

Response: Legend was added to table 1.

• What these acronyms mean? PDI?

Response: It was corrected.

“Polydispersity index”

• What these acronyms mean? MIC/MBC/IZ?

Response: It was corrected.

“IZ: Inhibition Zone, *MIC: Minimum Inhibitory Concentration, *MBC: Minimum Bactericidal Concentration.”

• Why refer to table 1?

Response: It was corrected.

• Add to the legend of the figure what is the difference between Figure3A and Figure 3B.

Response: As you requested, a brief explanation was added in the caption of figure.3 (page 8), and a more detailed statement was added to the explanations embedded in the manuscript (page 7).

• Why put this reference (68)? Why don't present the GRAS reference where it is possible consult directly the EOs that are allowed? It is essential to include in this work the list of allowed EOs that are on the GRAS list.

Response: Allowed EOs by GRAS are added. New reference to that point was also added. In addition, now, newly inserted reference 68 is also implying to acceptability of EOs by GRAS.

“Additionally, majority of those well-known EOs (like: basil, bergamot, black pepper, cassia, clove, coriander, fennel, ginger, lemon, lemongrass, oregano, peppermint, rosemary, thyme, and etc.), have been enumerated as Generally Recognized As Safe (GRAS) [68], that can synergistically reduce pathogenic food-borne microorganisms (phytopathogenic bacteria like: Lactobacillus, Salmonella species, and fungal species) in crops, poultry meat, yoghurt, dairy, and other food products [34, 41, 69].”

• Authors should explain what the meaning of "edible films". This term is controversial in the scientific community so it is important to explain exactly the characteristics of this film and how they are apply or relate to food.

Response: In the first paragraph of page 10, it has been completely clarified.

“To solve this problems, wide range of studies have been focused on investigating an-ti-microbial roles of biopolymer films through incorporation of EOs in the form of edible films) into food based products. Edible films have been applied as a thin layer of film or coating, surfaced on food with no detrimental effects on health system. To differentiate them, those layers which are formed directly on the food surface, they will be renamed “edible coatings”. Whereas, if they are separately wrapped on food surface, they will be called “edible films” [74, 85-87].”

• Mention some of the various food engineering processes used.

Response: It was added at the end of page 10.

“In this approach, normally food grade ingredients (lipophilic active ingredients integrated into aqueous-based systems) are used for formulation of emulsifiers through various food engineering processes [98, 99]. Speaking on food engineering processes, it has been implied to all methods aimed at food preservation and stabilization through food processing, evaporation, freezing, three-dimensional food-printing, pasteurization, and FP, [98, 99].”

• What these acronyms mean?

Response: As it has been specified from the first repetition in the manuscript (page 2), “NEs” is abbreviated form of “nanoemulsions”. After the first usage in complete form, it has been abbreviated in the second usage, and so on.

• The reference?

Response: The reference was added.

• Why is making the reference to table 1? Where in table 1 is this information? The table 1 must be improved.

Response: As you said, it was an incorrect referring and was deleted. All of the referring to table 1 was checked.

• What do you mean by this? a bit?

Response: According to the articles, it was checked and corrected.

• Reference?

Response: based on the comment from the pdf file, Reference was added.

• Reference?

Response: based on the comment from the pdf file, Requested references were inserted in the paragraph.

• Must explain what “emulsion phase inversion” is.

Response: It was explained in the page 12.

“Whereas, in thermal-based methods, preparation of NEs is done through making changes in the temperature (or changing in electrical charge and pH), leading to phase inversion temperature (changes in temperature leading to make a shifting the emulsifier affinity from one phase to the other, and making more stable emulsion) or phase inversion com-position (changing the composition at constant temperature during emulsification procedure) [89, 103, 124].”

• Must explain what is "phase inversion temperature" and "phase inversion composition".

Response: It was explained in the page 12.

“Whereas, in thermal-based methods, preparation of NEs is done through making changes in the temperature (or changing in electrical charge and pH), leading to phase inversion temperature (changes in temperature leading to make a shifting the emulsifier affinity from one phase to the other, and making more stable emulsion) or phase inversion com-position (changing the composition at constant temperature during emulsification pro-cedure) [89, 103, 124].”

• What do you mean by this?

Response: It was corrected in page 13.

“As it has been mentioned earlier, the main strategy served in ultrasonic-based approaches is making strong shearing, and mechanical disturbing forces. This aim comes true by us-age of high-intensity waves, being resulted in making droplets in decreased size without any extra need to other requirements for preparation of NEs, and with improvement in mass transferring [136-138].”

• What is "PDI index"?

Response: It was completely described in the content of manuscript. * PDI: Polydispersity Index.

• What these acronyms mean? Add a legend

Response: The legend was added to table 2.

• Please add the year.

Response: All of years of publications were inserted in Table 2.

• The meaning of the acronym.

Response: It was mentioned in the last paragraph before table 2.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

I thank the authors for all the effort, rigor and dedication in the responses they send. The new version of the manuscript has a significantly improved quality, I have no objection in the publication of this paper in Coatings in its current form.