Deodorizing Activity of Hop Bitter Acids and Their Oxidation Products Against Allyl Methyl Sulfide, a Major Contributor to Unpleasant Garlic-Associated Breath and Body Odor

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper "Deodorizing Activity of Hop Bitter Acids and Their Oxidation Products Against Allyl Methyl Sulfide, a Major Contributor to Unpleasant Garlic-Associated Breath and Body Odor" explores a practically significant and interesting deodorizing effect of a simple natural component on a common organic compound. The idea of the article is interesting, the research is conducted at an acceptable level, and while the overall depth of analysis is moderate, it is sufficient for publication. In my opinion, after minor revisions, the manuscript can be published in the Cosmetics journal.

Comments:

1. Introduction lacks sufficient coverage of the current state of research in the field. Please expand the introduction to include existing deodorizing approaches based on both physical and chemical principles. Special attention should be paid to the chemical transformation of AMS and the applicability of deodorizing approaches to its transformation products.
2. The purpose of Figure 1 is unclear. If it is from literature, a citation is needed; if not, it should be moved to another section. Additionally, the retention time in Figure 1 differs from other results (e.g., Figure 2).
3. Section 2.3: Please provide a more detailed explanation of how the studied fractions were obtained. All numerical values and ratios must be clearly clarified. Currently, the methodology for generating the fractions is difficult to follow.
4. The composition of Peak 2 in Figure 2 conflicts with the results in Table 2. What does the signal at 13–15 minutes (Figure 2) correspond to?
5. Lines 470–476: The references to "Compound A, C, D" are ambiguous. The authors should explicitly identify these compounds.
6. The Results and Discussion section should be divided into subsections to improve clarity, as the transitions between experiments are currently hard to follow.

Author Response

please see the attachment

 

Comments:

1. Introduction lacks sufficient coverage of the current state of research in the field. Please expand the introduction to include existing deodorizing approaches based on both physical and chemical principles. Special attention should be paid to the chemical transformation of AMS and the applicability of deodorizing approaches to its transformation products.
2. The purpose of Figure 1 is unclear. If it is from literature, a citation is needed; if not, it should be moved to another section. Additionally, the retention time in Figure 1 differs from other results (e.g., Figure 2).
3. Section 2.3: Please provide a more detailed explanation of how the studied fractions were obtained. All numerical values and ratios must be clearly clarified. Currently, the methodology for generating the fractions is difficult to follow.
4. The composition of Peak 2 in Figure 2 conflicts with the results in Table 2. What does the signal at 13–15 minutes (Figure 2) correspond to?
5. Lines 470–476: The references to "Compound A, C, D" are ambiguous. The authors should explicitly identify these compounds.
6. The Results and Discussion section should be divided into subsections to improve clarity, as the transitions between experiments are currently hard to follow.
7. Response 1;

   Thank you very much for taking the time to review our manuscript. We described briefly existing deodorizing methods and their deodorizing mechanisms, including examples of methods based on physical and chemical principles. We discuss in this paper the chemical transformation of AMS and the applicability of the deodorization approach to the transformation products. Added text; P4, line 57-70.

8. Response 2. We agree with this comment. Therefore, we have moved Fig. 1(f) to Fig. 5. As you have specified, the retention time of HPLC is different between Fig. 1 and Fig. 5, but this is due to the different HPLC conditions. HPLC conditions were added to each figure. Figure 3. P 19(?) and Figure 5. P 25?
9. Response 3. 

   We have added a figure as Figure 2 showing the methods of the extraction and fractionation of the deodorizing active substances to facilitate understanding of the methods.

   The figure is shown in P10.

10. Response 4. Sorry for the incomplete figure. I added an arrow in the figure. Revised Figure 3 is shown in P2.

11. Response 5. We feel that it would be difficult to discuss this further for LC/MS/MS analysis. We would like to continue to consider other instrumental analysis.

12. Response 6. We divided the Results and Discussion section into two sections, 3.1. Potent deodorizing compounds against AMS extracted from hop cone powder, and 3.2 Deodorizing mechanism of humulinone against AMS. 

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

The manuscript "Deodorizing Activity of Hop Bitter Acids and Their Oxidation Products Against Allyl Methyl Sulfide, a Major Contributor to Unpleasant Garlic-Associated Breath and Body Odor" reported bioactive effects of hop bitter acids and their derivatives in terms of their deodorizing properties. My general impression is that the authors have successfully utilized advanced analytical techniques to accomplish the objectives of the study. I must admit that I am not entirely familiar with this methodology, and as such, I may not be fully equipped to provide a conclusive evaluation of the paper. I therefore leave it to the editors to determine whether an additional reviewer should be consulted.

I will provide a few comments that could contribute to improving the quality of the paper.

• Abstract

line 17. “cohmulinone” should be corrected to “cohumulinone”

 

• Introduction

line 44.  “Humulus lupulus“ should be corrected to “Humulus lupulus L.“

 

• Material and Methods

I don't see the relevance of Section 2.2. Preparation of Screening Samples and Analysis of Deodorizing Activity, since the results from this part of the study are not presented, and the primary aim of the paper is to demonstrate the effects of hop-derived bitter acids.

 

• Overall, I find the manuscript suitable for publication after the revisions.

 

 

Author Response

Please see the attachment.

I will provide a few comments that could contribute to improving the quality of the paper.

• Abstract

line 17. “cohmulinone” should be corrected to “cohumulinone”

Response 1. 

Thank you very much for taking the time to review this manuscript. I also thank you for pointing this out. I changed “cohmulinone” to “cohumulinone”.

 

• Introduction

line 44.  “Humulus lupulus“ should be corrected to “Humulus lupulus L.“

Response 2. I changed “Humulus lupulus” to “Humulus lupulus L.”

• Material and Methods

I don't see the relevance of Section 2.2. Preparation of Screening Samples and Analysis of Deodorizing Activity, since the results from this part of the study are not presented, and the primary aim of the paper is to demonstrate the effects of hop-derived bitter acids.

response 3. 

 I agree with you. I changed the title Preparation of Screening Samples and Analysis of deodorizing activity to Analysis of deodorizing activity and deleted relevant text.

 

• Overall, I find the manuscript suitable for publication after the revisions.

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript “Deodorizing Activity of Hop Bitter Acids and Their Oxidation Products Against Allyl Methyl Sulfide, a Major Contributor to Unpleasant Garlic-Associated Breath and Body Odor” is an interesting work studying the properties of hop bitter acids and their oxidation products as deodorants against allyl methyl sulphide. The topic is very interesting and of great importance for science and everyday life. The methods used to obtain the samples and to analyze the deodorizing activity are explained in detail. The results are described and illustrated with figures and tables. The authors discuss their results, comparing them with the results of other researchers.

I have only some suggestions for editing for the authors:

1. Please correct the error on line 17 – “hope”, correct the size of the text on line 403, and lines 472-478, and align the content on lines 237-238, 313-314.
2. The chemical formulas in Figure 1 need to be redrawn to be clearer, of the same size, and with higher resolution. The size and font of the notation below the chromatogram (f) should also be adjusted.
3. The size of the text in tables 1-3 should be reduced.
4. The size of the figures 3-5 should be reduced.

Author Response

 Please see the attachment.

Comment 1. Please correct the error on line 17 – “hope”, correct the size of the text on line 403, and lines 472-478, and align the content on lines 237-238, 313-314.

Response 1. 

Thank you very much for taking the time to review our manuscript. I also thank you for your remarks regarding the following points. The letter "hope” changed to “hop” (P3, line 48) and correct the size of the text on line 403, and lines 472-478, and align the content on lines 237-238, 313-314.

Comment 2. 

The chemical formulas in Figure 1 need to be redrawn to be clearer, of the same size, and with higher resolution. The size and font of the notation below the chromatogram (f) should also be adjusted.

Response 2. 

The chemical formulas in Figure 1 are redrawn to be clearer. (P6 and P25, Figure 5).

Comment 3. 

 The size of the text in tables 1-3 should be reduced.

Comment 4. 

The size of the figures 3-5 should be reduced.

Response 3. and 4.

The size of the text in tables 1-3 were reduced. P18 (Table 1), P19-20 (Table 2), P25 (Table 3).

The size of the text in figures 3-5 were reduced. P23-24 (Fig. 4), P28 (Fig. 6), P30 (Fig. 7).