Evaluation of the Soil Type Effect on the Volatile Compounds in the Habanero Pepper (Capsicum chinense Jacq.)

Round 1

Reviewer 1 Report

The author provided the evaluation of the soil effect on the volatile compounds in Habanero pepper. This results help to understand the role of the soil in the aroma of the Habanero pepper in the Yucatan Peninsula and could be used by farmers in the region to select the soil according to the desired aroma characteristics. However, the overall amount of experiments in this paper is lower than these of other papers published by Horticulturae. I think that the experiment is inadequate, and more experimentals in physiological and morphological data should be added in different soil conditions.

Author Response

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Reviewer 2 Report

In this paper, the authors are evaluating the effect of soils on the volatile compounds in Habanero pepper grown in Yucatan, Mexico. I found this paper and the conclusions very interesting, and my comments are presented below:

Overall comments:

• I find this paper scientifically sound, but I detected some minor linguistic errors that should be addressed.
• The references are all listed and formatted according to the guidelines for the authors.
• The material and methods section needs some restructuring, but the results are sound.
• I found great similarities in text with previous work from the authors (mainly in the Material and methods section). I understand that the methodology used here is like that in previous work so I would advise the authors take time and rewrite the Introduction to some extent to reduce self-plagiarizing.

Specific comments:

• On line 62 please use nitrogen
• I suggest restructuring the Material and methods section in the following way, so it is easier to follow:
• Start with the Growing conditions section describing the field experiment and soil and pepper samples
• Then combine the first four sections into soil analysis section
• Continue with chemical and statistical analyses sections (as in the original manuscript)
• Please clearly state the source of the soils used in the experiment (was it commercial soil, was it sources locally and from where)
• Please clearly state the source of the plant samples used for the experiment (commercial seed, seed bank – if so, provide a reference number) as well as the number of seedlings used per variety/soil type
• Please rephrase on line 135 “as received” to “after harvest”
• Standardize your units. In some places you use x/y format, while in other places you use x y^-1
• In the results section please change the name of the “Statistical analysis” subsection to a more descriptive title (such as “Interaction of factors influencing the composition of volatiles”)
• On line 285 please use “physico-chemical”
• On line 292 please use standard formatting for the author of Artemisia absinthium.
• Please refrain from using the term “more” when describing concentrations and rather use term “higher” (example lines 290 and 299)
• On line 317 it would be better to swap the words, so it says “odor-active molecule”.
• On line 335 please rephrase the sentence. Black soils cannot favor production.
• I highlighted the sentences in your manuscript that need to be improved language-wise. Please find them in the attached pdf and have a native English speaker to read the manuscript.

Comments for author File: Comments.pdf

Author Response

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Reviewer 3 Report

In the manuscript ‘Evaluation of the soil effect on the volatile compounds in Habanero pepper’, the authors aim to evaluate the effect of three different soil on the main volatile compounds in Habanero pepper, but they designed the experiment with two varieties in ripe and unripe degree of ripeness. Their results, discussion, as well as conclusion parts all descripted not only the soil, but also the variety and the degree of ripeness of Habanero pepper can significantly influence the concentration of the volatile compounds. The content of the article does not accord with its subject. Besides, there are many questions need to be revised.

1. The authors should explain how many samples used in ‘2.4 Sample preparation’?
2. Why they chose 1-Hexanol, hexyl-3-methyl butanoate, 3,3-dimethyl-1-hexanol and cis-3-Hexenyl hexanoate, only the four aroma as the main volatile compounds? How about other volatiles compounds?
3. 1 show the four main volatile compounds have a higher concentration in Habanero peppers harvested from plants grown on black soil (line 227-228), while, one variety was exhibited and did not state what was the variety? Moreover, the degree of ripeness seemed to have more effects on the concentration of the volatile compounds compared to soil.
4. Similarly, they used two varieties in Fig. 2, but not state the degree of ripeness. In my opinion, if they want to use different varieties and different degree of ripeness of Habanero pepper to certify their conclusion, they should use all Habanero pepper samples in Fig. 1 and Fig. 2, including Mayapan and Jaguar variety, ripen and unripen.
5. I don’t think the results in this study can support their conclusion, for example, ‘These results suggest that the black soil favors the production of volatile compounds in the Habanero pepper, …’ in line 335-337. The influences of different soil may be not universal.

Author Response

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Reviewer 4 Report

The manuscript entitled “Evaluation of the soil effect on the volatile compounds in Habanero pepper” describes the change in the phytochemical profile of a well-known pepper “Habanero” affected by soil type. There are various studies on Habanero pepper volatile compounds, however, this study is novel in the evaluation of soil effect on phytochemical nature and quantity. Altogether, the manuscript needs major revision addressing the following questions and concerns:

1- The title is ambiguous as it is not clear which feature of soil has been evaluated. So, it may be better to write the title as “soil type”. Please also add the species name in parentheses: (Capsicum chinese Jacq.).

2- However manuscript is well-written in some parts but a structural and grammatical language revision is needed to reach a level acceptable for publication. I have highlighted some cases in minor comments.

3- Authors can first present all the identified phytochemicals affected by three soil types (for example all phytochemicals more than 0.5% of essential oil) and they can then compare the selected phytochemicals under the selected soil types.

4-The soil analysis just includes 4 variables (CEC, bulk density, ….). I suggest authors analyze other soil attributes like pH, EC, lime content, organic matter, organic carbon, NPK content and clay/silt/sand ratio for three analyzed soil classes and perform a correlation analysis among phytochemical constituents and all soil attributes to find out most important factors (The authors have done these analyses on soil in their previous paper published in Agronomy).

5- Is the seed obtained from a company and they bred material? Please write the details origin of the seed. Also, determine if pruning has been performed on the pepper plants?

6- What criteria were used to determine the ripeness of fruit and harvest time? To have even fruit with a similar maturity stage, it should determine based on color using a colorimeter or color charts. Please clarify and add to M&M.

7- Which kind of research design is used for the experiment. It seems it’s a factorial with three factors. Please clarify.

8- Why besides the compounds with known standards, other phytochemicals have not been identified using available libraries like NIST as there are other micro-peaks in the chromatograms showing different constituents. In addition, clarify where you have obtained the standards?

9- One of the most important variables for such studies is the essential oil yield as the authors have mentioned this plant as an important crop in the food industry. So, if the authors have data regarding essential oil percentages, I recommend adding it to the manuscript.

10- Why the authors have not represented cultivar×soil×harvest stage result as it is clear from table 4 the triple effect is significant.

11- The data should bring in the results section, not in the conclusion.

Minor comments:

Please order keywords alphabetically.

L31-32: Redundancy: distinguishes

L33-L35: The sentence is incomplete and needs a verb or conjunction.
L40-41: developed by fruit → Produced in fruit

L41-42: In a previous study conducted by SosaMoguel et al. [8] are reported → In a previous study, Sosa Moguel et al. [8] reported.

L45: the largest constituents → as the largest constituents; For this reason, → Therefore,

L52: species (Jaguar or Mayapan variety) → variety (Jaguar or Mayapan).

Author Response

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Round 2

Reviewer 1 Report

The author has revised the paper as requested by the reviewer and the paper can be accepted.

Author Response

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Reviewer 2 Report

I would like to thank the authors for addressing all issues raised. I would still advise that the manuscript be proofread by a native English speaker. Please check carefully the text for errors, especially the parts you have rewritten.

Author Response

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Reviewer 3 Report

1.  In Figure 2,  the authors analysed  the concentration  of volatile compound, but did not indicate clearly  which soil the plants grown on.

2. Figure A4 should be in the manuscript rather than in  Appendix and .the result section should be correspondingly improved. 

3. The icons in Figure 1 should be different shapes between Unripe and ripe samples, such as circle and triangle. Or the lines are solid and dashed to make sure  color blind users can read your paper.

Author Response

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Reviewer 4 Report

Thank the authors for performing the revisions and corrections. I still think a correlation analysis (table or heat map) could further help the better presentation of the results. Furthermore, a final check of English structure, punctuation, and grammatical errors is recommended.

Author Response

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Author Response File: Author Response.pdf