Effects of Hexanal Supplementation on Volatile Compound Profiles and Quality Parameters of ‘Fuji Kiku’ Apples During Cold Storage and Shelf Life
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
Effect of hexanal on apperance and VOCs in apple fruit during storage and subsequent shelf life were observed in this paper. The topic was interesting and applicable, and the experiment design was sound. However, some information authors should provide and pay more attention before accept.
1-provide the photos of apple fruit in storage and shelf life, which show us the overall color changes;
2-the mechanism of hexanal on color changes can be discussed more comprehensively;
3-check the spelling of "during", some of them are "durning";
4-In Introduction, application of hexanal on fruit, advantage and disadvantage, can be sumarized;
5-volatile compounds usually shortened as VOC, not VC;
6-Is there results about hexanal on the basic quality of apple fruit, such as TSS, Ascorbic acid content, total acid content? It is better providing the information;
7-How the sampling time determined?
8-How the concentration of hexanal determined, as well as the treatment time?
Author Response
Response to Reviewer 1 Comments
We have been through all of the your comments, which we believe have helped us to improve the presentation of our study for the Agronomy. For your convenience, we have included below the full listing of your comments and our replies according to changes and modifications that have now been made to the original manuscript. We thank the Reviewer 1 for the supportive comments, and we have tried to satisfactorily address the modifications requested, as detailed below.
Effect of hexanal on apperance and VOCs in apple fruit during storage and subsequent shelf life were observed in this paper. The topic was interesting and applicable, and the experiment design was sound. However, some information authors should provide and pay more attention before accept.
1-provide the photos of apple fruit in storage and shelf life, which show us the overall color changes;
Our reply: These are the only photos taken at the end of the storage period. The first photo (left) represents the control group, while the second photo (right) shows apples from the hexanal-treated group. Unfortunately, we do not have additional photos that could indicate changes in color during storage or shelf life. We consider CIE L*, a*, b* and delta E parameters for both hexanal and control group more appropriate.
2-the mechanism of hexanal on color changes can be discussed more comprehensively;
Our reply: In the discussion section, we elucidated the mechanism by which hexanal inhibits color development and provided examples from another relevant research. [L: 367-372]
3-check the spelling of "during", some of them are "durning";
Our reply: We appreciate your identification of the error. The text has been amended accordingly.
4-In Introduction, application of hexanal on fruit, advantage and disadvantage, can be sumarized;
Our reply: Agree. In the introduction section, we have added a discussion on the advantages and disadvantages of different types of applications of hexanal to fruit. [L: 57-65, 74-79]
5-volatile compounds usually shortened as VOC, not VC;
Our reply: Thanks for this remark, we have done as requested.
6-Is there results about hexanal on txit, such as TSS, Ascorbic acid content, total acid content? It is better providing the information;
Our reply: We did not determine the basic parameters of apple quality, as we focused on VOCs, which was also the main purpose of the study.
7-How the sampling time determined?
Our reply: The sampling time was determined by encompassing multiple periods during storage. Given that apples are typically stored for several months and commence losing their aroma after an extended period, a longer storage duration was selected. For the shelf life assessment, the objective was to evaluate whether volatile organic compounds (VOCs) in apples are retained even after prolonged exposure to room temperature. The 7-day period of shelf life also corresponds to the time required for apples to reach retail shelves. For comparative purposes, measurements were taken immediately following the conclusion of storage, and the shelf life was extended up to 14 days.
8-How the concentration of hexanal determined, as well as the treatment time?
Our reply: The concentration of hexanal applied was chigher than the endogenous content in apples but below levels that could potentially exert toxic effects on the apple tissue. Hexanal was maintained in the chamber throughout the duration of cold storage; consequently, the treatment duration was determined based on the storage period of the apples. We included this information in the Material and method section.
Yours sincerely,
Erika Jesenko
Corresponding Author On behalf of all the authors
Author Response File:
Reviewer 2 Report
Comments and Suggestions for Authors
This study describes the effect of hexanal on the concentration of volatile compounds in the ‘Fuji Kiku’ apples during long cold storage and shelf life.
Although the investigation has several data related to the compounds responsible for the color and aroma of apple fruits, using hexanal to enhance the longevity of apple fruits was previously studied by several researchers; therefore, the authors should focus more on the importance of their study and how it is different from the previous ones.
There are some points need to be clarified, as follows:
1. There is no information about fruit decay caused by cold storage or microorganisms.
2. L66: papayas [17]
3. L91: 24 or 25 weeks
4. L96: delete after
5. L104: N=12 or N=15
6. In Table 1: why ΔE was not calculated for the control fruits.
7. Under Table 1: write what these numbers are and how many replicates and if it is with SD or SE.
8. Title of Table 1 changed to: Flesh firmness, and CIE …..
9. L176: delete from the
10. L213: delete produced by apple fruits
11. L230: storage temperature than other
12. Some sentences in the results part should be moved to the discussion part, such as sentence in lines 170-171, 202-204, and 252-253.
13. Figure 2 is not mentioned in the text.
14. Under Table 2: give the meaning of avg and sd.
15. L298 under Table 2: what the meaning of these letters a-f or references mentioned.
16. L329: cold storage or shelf life.
Author Response
Dear Reviewer 2,
We have been through all of the your comments, which we believe have helped us to improve the presentation of our study for the Agronomy. For your convenience, we have compiled a detailed response file that addresses each of your comments. This document outlines the changes and modifications made to the original manuscripts. We are especially grateful for your supportive remarks and have made every effort to address the requested revisions to your satisfaction. The detailed responses and corresponding revisions are outlined in the file. Thank you once again for your time and insights.
Yours sincerely,
Erika Jesenko
Corresponding Author On behalf of all the authors
Author Response File: 
Author Response.docx
Reviewer 3 Report
Comments and Suggestions for Authors
The study on hexanal supplementation in the storage atmosphere of 'Fuji Kiku' apples provides valuable insights into improving postharvest aroma retention. The research is thorough, employing advanced techniques like gas chromatography/mass spectrometry (GC/MS) and partial least squares discriminant analysis (PLS-DA) to analyze volatile compound (VC) profiles. By focusing on a specific apple variety, the study addresses an important gap in the literature, highlighting hexanal's potential to enhance aroma-related compounds. The findings indicate that hexanal treatment stimulates the production and retention of key esters such as hexyl acetate and ethyl 2-methylbutanoate, critical for the characteristic aroma of apples. However, the results for firmness and color development are less conclusive, suggesting that hexanal's effects may depend on factors such as cultivar characteristics and storage conditions.
Despite its strengths, the study has some limitations. The research focuses solely on 'Fuji Kiku' apples, limiting its generalizability to other varieties. The lack of significant differences in firmness and color between treated and control samples raises questions about hexanal’s broader efficacy. While the study successfully demonstrates the influence of hexanal on VC profiles during cold storage and short-term shelf life, its effects diminish over extended shelf life, particularly at higher temperatures. This temporal limitation could pose challenges for commercial applications, where storage durations and conditions vary. Moreover, the absence of sensory evaluations leaves a gap in understanding the practical implications of VC changes for consumer experience.
To enhance the study's impact, future research could include comparative analyses across multiple apple varieties to generalize the findings. Sensory evaluations would provide a direct link between chemical changes and consumer preferences, strengthening the practical relevance of the results. Dose-response studies could optimize hexanal concentrations for specific storage conditions, and mechanistic investigations into the enzymatic pathways influenced by hexanal would offer deeper insights. Additionally, exploring combinations of hexanal with other postharvest technologies, such as modified atmosphere packaging or ethylene inhibitors, could extend its efficacy. While the study demonstrates hexanal's potential to modulate aroma-related compounds, further research is needed to refine its application for broader adoption in the fruit industry.
Questions:
1. How does hexanal treatment affect consumer perceptions of apple quality, especially in terms of taste and aroma, when evaluated through sensory analysis?
2. Can the combination of hexanal with other storage technologies enhance its efficacy in maintaining apple quality during prolonged storage and distribution?
3. What mechanisms underlie the variability in hexanal's effects across different apple cultivars and storage conditions?
Author Response
Dear Reviewer 3,
We have been through all of the your comments, which we believe have helped us to improve the presentation of our study for the Agronomy. For your convenience, we have compiled a detailed response file that addresses each of your comments. This document outlines the changes and modifications made to the original manuscripts. We are especially grateful for your supportive remarks and have made every effort to address the requested revisions to your satisfaction. The detailed responses and corresponding revisions are outlined in the file. Thank you once again for your time and insights.
Yours sincerely,
Erika Jesenko
Corresponding Author On behalf of all the authors
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Comments and Suggestions for Authors
Authors have replied all my concerns, and yhis paper can be accepted in the present form. However, photos of treatments, decay rate, and basic quality attributes, can be determined in the further research.
Author Response
Dear Reviewer,
We express our sincere gratitude for your comprehensive review and constructive comments. We are confident that your feedback will contribute to the enhancement of our future studies.
Erika Jesenko
Corresponding author
For and on behalf of all of the authors
Reviewer 2 Report
Comments and Suggestions for Authors
The authors addressed all comments, and the manuscript was markedly improved.
Author Response
Dear Reviewer,
We express our sincere gratitude for your comprehensive review and constructive comments.
Erika Jesenko
Corresponding author
For and on behalf of all of the authors
Reviewer 3 Report
Comments and Suggestions for Authors
The revised manuscript, "Effects of Hexanal Supplementation on Volatile Compound Profiles and Quality Parameters of ‘Fuji Kiku’ Apples During Cold Storage and Shelf Life," demonstrates notable improvements, particularly in the clarity of data presentation and the detailed exploration of volatile compound profiles. The authors have effectively addressed prior concerns, especially regarding the role of hexanal in promoting key esters and alcohols that enhance apple aroma. The inclusion of partial least squares discriminant analysis strengthens the manuscript by providing clear distinctions between treated and control samples, adding depth and rigor to the findings.
The authors have made commendable efforts in refining the methodology and presenting the results in a more accessible and scientifically rigorous manner. The detailed response file indicates their thoughtful consideration of reviewer comments, ensuring the manuscript is more comprehensive and impactful. This study highlights the practical potential of hexanal for improving postharvest quality, offering significant insights that are relevant to both academic researchers and the horticultural industry.
While the manuscript is significantly improved, broader applicability to other apple varieties and the inclusion of sensory analysis to validate the chemical findings would enhance its practical relevance. Overall, the revisions have elevated the quality of the manuscript, making it a valuable contribution to the field of postharvest science. I recommend acceptance with minor editorial adjustments
Author Response
Dear Reviewer,
We express our sincere gratitude for your comprehensive review and constructive comments. We are confident that your feedback will contribute to the enhancement of our future studies.
According to your comment 'I recommend acceptance with minor editorial adjustments ' unfortunately, we do not understand or have anything else to edit.
Erika Jesenko
Corresponding author
For and on behalf of all of the authors
