Skin Byproducts of Reinhardtius hippoglossoides (Greenland Halibut) as Ecosustainable Source of Marine Collagen

Round 1

Reviewer 1 Report

Comments

1. The purpose and objectives of the research are not formulated in the introduction, it is necessary to correct this. According to the goals and objectives, it is necessary to build the conclusions of the research.

2. In the experimental part, you can specify the freeze drying conditions. On microphotographs of collagen after freeze-drying, the fibrillar structure of collagen is usually clearly visible. It is barely visible in the microphotographs in this publication, although the magnification is sufficient. I see no reason to give three micrographs of each sample, because nothing new is visible when the picture is enlarged.

3. In Figure 1, remove the values ​​"0 and "10." at the origin. At the intersection of the ordinate axes, it is not customary to indicate two values.

4. The list of references should include studies performed on the problem over the past 5 years. This indicates the urgency of the problem. More than half of the list of references do not comply with this rule. You need to replace some of the links with new ones.

Comments for author File: Comments.pdf

Author Response

1. The purpose and objectives of the research are not formulated in the introduction, it is necessary to correct this. According to the goals and objectives, it is necessary to build the conclusions of the research.

Reply: Thank you for your comments, dear reviewer. We added to the introduction the purpose and objectives of this research. The reviewer can see the changes in the last paragraph of the introduction. The conclusions were revised also taking into consideration this comment in the conclusion section of the manuscript.

2. In the experimental part, you can specify the freeze drying conditions. On microphotographs of collagen after freeze-drying, the fibrillar structure of collagen is usually clearly visible. It is barely visible in the microphotographs in this publication, although the magnification is sufficient. I see no reason to give three micrographs of each sample, because nothing new is visible when the picture is enlarged.

Reply: Thank you for the revision. We add the specific freeze-drying conditions in the section “2.2 Collagen extraction from fish skins”. The microphotographs enable us to see a different magnification of each collagen sample according to the extraction methodology. In our opinion, different magnifications allow for showing some details of each material, such as the orientation of collagen and its density too. For this reason, we selected different micrographs of the SEM images. These micrographs showed clear differences in the surface of Halibut collagens.

3. In Figure 1, remove the values ​​"0 and "10." at the origin. At the intersection of the ordinate axes, it is not customary to indicate two values.

Reply: Dear Reviewer, figure 1 doesn´t have 0-10 values. We think this comment was misunderstood because it is not applied to figure 1.

4. The list of references should include studies performed on the problem over the past 5 years. This indicates the urgency of the problem. More than half of the list of references do not comply with this rule. You need to replace some of the links with new ones.

Reply: Dear Reviewer, thank you for your pertinent comment. We will add new references to improve the list of references.

Reviewer 2 Report

The authors presented a paper on extraction of collagen from Reinhardtius hippoglossoides (Greenland halibut). The authors have done extensive work and I find that the paper will be of interest to readers of applied sciences. Please see my minor comments below which will help improve the quality of the manuscript.

pg 3 100-101: Has the NaOH based removal of non collagenous proteins been tested before? If so, please cite relevant references.

pg 3 Line 110-111: Define AcOH before first use.

pg 13 441-442: I am skeptical of the "first time" claim. Particularly these articles claim extraction of collagen from this particular species:

1. Studies on extraction of collagen in fish skin  [2006] .Noguchi, M.(Tottori-ken. Industrial Research Inst. (Japan)); Arifuku, I.; Takahashi, Y.; Yamashita, A.;

2. Sousa, S.C.; Vázquez, J.A.; Pérez-Martín, R.I.; Carvalho, A.P.; Gomes, A.M. Valorization of By-Products from Commercial Fish Species: Extraction and Chemical Properties of Skin Gelatins. Molecules 2017, 22, 1545. https://doi.org/10.3390/molecules22091545

 

Author Response

The authors presented a paper on extraction of collagen from Reinhardtius hippoglossoides (Greenland halibut). The authors have done extensive work and I find that the paper will be of interest to readers of applied sciences. Please see my minor comments below which will help improve the quality of the manuscript.

pg 3 100-101: Has the NaOH based removal of non collagenous proteins been tested before? If so, please cite relevant references.

Reply Thank you for the comment. We add relevant references

pg 3 Line 110-111: Define AcOH before first use.

Reply Thank you for the comment. We add this information.

 

pg 13 441-442: I am skeptical of the "first time" claim. Particularly these articles claim extraction of collagen from this particular species:

1. Studies on extraction of collagen in fish skin  [2006] .Noguchi, M.(Tottori-ken. Industrial Research Inst. (Japan)); Arifuku, I.; Takahashi, Y.; Yamashita, A.;
2. Sousa, S.C.; Vázquez, J.A.; Pérez-Martín, R.I.; Carvalho, A.P.; Gomes, A.M. Valorization of By-Products from Commercial Fish Species: Extraction and Chemical Properties of Skin Gelatins. Molecules 2017, 22, 1545. https://doi.org/10.3390/molecules22091545

Reply: We change the sentence to be more concise. We addressed this because it is a new application for the Greenland halibut R. hippoglossoides fish.

Author Response File: Author Response.docx