Characterization of Changes in Ripening Process of Volatile Apple Compounds Based on HS-SPME-GC-MS Analysis
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsGeneral comments
The manuscript focuses on evaluating aromatic compounds in three apple varieties. Besides rOAV evaluation, the manuscript has no new approach to volatile analysis.
The authors have used terms like peel and skin; pulp and flesh at various locations which need to be made uniform throughout the manuscript. It is suggested to use the terms peel and pulp throughout instead of skin and flesh, which represent animal body parts.
In the caption of Figure 1, the authors have used the terms grain length and width for the fruit parameters which need to be rectified.
The figure captions throughout the manuscript need to be checked.
The alphabet mentioned in the figure should be properly represented in the figure caption.
The details of the statistical method, need not be explained in the figure caption
Specific comments
Lane 88-90: Figures 3 & 4, 6 & 7 represented the same results, hence any one of the figure sets can be retained.
Lane 106: Mention the average day and night temperatures of the growing conditions.
Lane 109-112: The starch Index method followed here is a destructive method, Doesn’t the destruction of fruit and the chemicals used in the starch indexing alter the volatile components and their release pattern?
Lane 115: The authors mentioned the refractor used was hand-held refractometer but the model mentioned corresponds to a digital refractometer, so accordingly it may be corrected
Lane 120: The methodology for the parameters Fruit shape index mentioned in figure 01(e) is not given in the materials and methods section
Lane 289: Variety name is incomplete “ Golden ………………..”
Lane 335-338: The sentence is lengthy and not clear, please revise it to convey the proper meaning
Lane 342-344: The authors have used the words downregulation and upregulation for the increase and decrease of volatile compounds which may not be appropriate as those words are used for gene expression studies
Lane 452-453: The authors have used the words downregulation and upregulation for the increase and decrease of volatile compounds which may not be appropriate as those words are used for gene expression studies
In Figure 2: The vertical axes labels need to be checked and rectified; The caption needs to be corrected concerning change of the terms (A) Skin and (B) Meat
In Figure 3: Caption needs to be corrected (A) description is missing
In Figure 4: n=3 is repeated twice, one can be removed
Comments on the Quality of English LanguageThe English language use is very poor and needs revision, especially concerning the punctuation used throughout the manuscript.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe aim of the present study was to identify and to characterize the aroma compounds found in apple skin and flesh of three apple varieties at 4 different stages of maturity. The study could have important influence for apple growers of the aforementioned varieties as well for the consumers as a quality indicator. I find that the data analysis was well executed, however, the expression of the results obtained via GC-MS is flawed. More detailed comments are listed as bullet points as follows:
- Be careful to check and eventually remove any special characters throughout the manuscript.
- Line 75: wine is by the OIV definition a beverage produces exclusively from grapes, therefore I suggest you to replace the term "wine" with "fermented beverages" or something similar.
- Lines 93-96: Try to avoid repeating in sentences.
- Line 105: Remove the "." or restructure the sentence.
- Lines 126-127: Avoid repeating sentences.
- Chapter 2.3: Did you encounter any problems regarding the oxidation of the samples during the extraction phase? In some cases, when the fresh fruits are analyzed, some antioxidants are added.
- Line 148: Avoid repeating in the sentences.
- Chapter 2.5: The calculation that you described for the quantitative method is not quantitative but it could be described as semi-quantitative. For an absolute quantitative method you would need to establish the calibration curves for each analyzed compound Also, since you expressed the results as equivalents of the internal standard, you must state also this fact in the manuscript, otherwise the concentration unit mg/kg is not correct. Please revise.
- Chapter 2.8: Could you name the test you used for the normality assumption? Also, could you confirm that the Tukey's test was used as a post-hoc test for comparing means?
- Line 197 and the Chapter 3.2: Please check the units of measure. It is very unlikely to me that a sample could have 1606.50 mg/kg of total volatile compounds.
- Figure 3: Please improve the resolution of the figure as the legend is not readable. Also, you could provide only one legend for all the plots since it is the same.
- Line 233: Did you mean "terpenes"? Please revise.
- Chapter 3.4: Several typos are detected; it becomes very difficult to read the manuscript. Please revise.
- Figure 3: I suggest to put it in the supplementary material - it seems to be redundant for the manuscript as it is difficult to follow.
- Figure 6: The letters "A" and "B" refers to what exactly? Please revise.
- Chapter 3.6: Based on which selection criteria were 17 volatile compounds selected for the rOAV analysis? Please explain.
- Supplementary table and throughout the manuscript.: it would be most useful if the authors could reference the source from where they compared experimental RI's with the theoretical ones.
Overall, I found the discussion section very insightful and interesting and I compliment authors for that. However, the representation of the results must be improved together with extensive English revision.
Comments on the Quality of English LanguageExtensive correction of the English language is requested.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsAuthors submited an original manuscript entitled: Characterization of changes in the ripening process of apple aromatic compounds based on HS-SPME-GC-MS analysis.
From the title, the term "aromatic" may be misunderstood. It should be used if the authors can ensure, using olfactometric tools, that all target substances are indeed responsable for the aroma. Otherwise, the term will certainly be misunderstood, understood as benzenoids and derivatives. The suggestion is change to "volatile".
Overall, the manuscript brings several well-discussed results, with a deeply approach.
References are relevant, updated, but some of them out of format.
Comments on the Quality of English LanguageNone.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThe only comment concerns to type of article: why essay? according to guidelines there are article and review.
however the type "essay" was interest-attractive
Author Response
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Author Response File: Author Response.pdf
