Combined Effect of Potassium Permanganate and Ultraviolet Light as Ethylene Scavengers on Post-Harvest Quality of Peach at Optimal and Stressful Temperatures

Round 1

Reviewer 1 Report

I am happy to inform you that I have noticed few minor points to be corrected.

Please, see the attached pdf file.

Comments for author File: Comments.pdf

Author Response

Dear Editor and Reviewers,

We would like to express our sincere appreciation for the time and effort spent by the three reviewers in the evaluation of our manuscript titled “Combined effect of potassium permanganate and ultraviolet light as ethylene scavengers on post-harvest quality of peach at stressful and optimal temperatures” (agronomy-1587640). Thank you very much for your positive and constructive comments and suggestions, which are very helpful for the improvement of our paper. We have considered the comments carefully and have revised the manuscript thoroughly based on the comments. We deeply appreciate your work, and hope that the corrections and responses will meet with your approval. Revised portions are marked, in different colours depending on the reviewers, in the revised manuscript and the point-to point responses to the comments are listed below in this cover letter. In addition, to improve the quality of the English language, the manuscript has been sent to a native English person specialized in the correction of scientific articles and subsequently check by us. We look forward to your information about our revised paper.

Best regards,

Yours sincerely,

Dr. José Ramón Acosta Motos

 Reviewer 1. (BLUE)

 Table numbering error in the main text.

• Special thanks for your good advice. We have careful revised the manuscript in order to correct the numbering errors. Lines 292, 305, 319, 329, 344, 348, 378 and 426.

 

Indications of the days of storage and description of the statistical analysis carried out in figures 2 and 3.

• Thank you very much for your suggestion. In order to incorporate the suggested improvements, the figure captions have been modified. Lines 410-411 for figure 2 and 565-567 for figure 3.

 

Indications on the Y-axis headings in figures 2a and 3a.

• Thank you very much for your advice. The titles of the axes have been revised as suggested by the reviewer. Lines 386 for weight loss figure and 543 for SSC.

Reviewer 2 Report

1. Why the RH in refrigarators was 80% and not 90-95%?
2. Did you measure Carbon dioxide, oxygen and ethylene production at day 0?

Author Response

Dear Editor and Reviewers,

 

We would like to express our sincere appreciation for the time and effort spent by the three reviewers in the evaluation of our manuscript titled “Combined effect of potassium permanganate and ultraviolet light as ethylene scavengers on post-harvest quality of peach at stressful and optimal temperatures” (agronomy-1587640). Thank you very much for your positive and constructive comments and suggestions, which are very helpful for the improvement of our paper. We have considered the comments carefully and have revised the manuscript thoroughly based on the comments. We deeply appreciate your work, and hope that the corrections and responses will meet with your approval. Revised portions are marked, in different colours depending on the reviewers, in the revised manuscript and the point-to point responses to the comments are listed below in this cover letter. In addition, to improve the quality of the English language, the manuscript has been sent to a native English person specialized in the correction of scientific articles and subsequently check by us. We look forward to your information about our revised paper.

Best regards,

Yours sincerely,

Dr. José Ramón Acosta Motos

Reviewer 2. (RED)

 

1. Why the RH in refrigarators was 80% and not 90-95%?

 

Thank you very much for your question. We decided to not set a uniform humidity in order to kept the natural humidity emitted by the fruits in the different conservation chambers.

 

1. Did you measure Carbon dioxide, oxygen and ethylene production at day 0?

 

The data for oxygen, ethylene and carbon dioxide were measured after 6 hours of storage but were not included in the original version due to the fact that  we did not consider them sufficiently relevant until atmospheric conditions were stable after three days of storage. The data at day 0 were as follows:

 

 

- O₂:

• NoES-R: 20.79 %
• ES-R: 20.9 %
• NoES-NoR: 20.56 %
• ES-NoR: 20.79 %

- CO₂:

• NoES-R: 0.40 mL kg^-1 h^-1
• ES-R: 0.40 mL kg^-1 h^-1
• NoES-NoR: 10.23 mL kg^-1 h^-1
• ES-NoR: 6.32 mL kg^-1 h^-1

 

- C₂H₄: 

• NoES-R: 0.62 mL kg^-1 h^-1
• ES-R: 0.28 mL kg^-1 h^-1
• NoES-NoR: 4.92 mL kg^-1 h^-1
• ES-NoR: 1.67 mL kg^-1 h^-1

 

However, we have introduced the data of the day 0 in the reviewed manuscript following the reviewer's suggestions in order to visually improve the evolution of the parameters represented. The above data have been included in Figures 1a, 1b and 1c between lines 200-220.

Reviewer 3 Report

The authors studied the effect of combined KMnO4 and UV on ethylene and peach postharvest quality.

 

Suggestions

 

L75. please provide harvest index of peaches

L87. which is the relation of KMno4 / sepiolite? mol/g. How many grams per filter?

L96. How did the UV light impact the filters if these were covered by paper?

L109. Explain in detail how the CCs were designed.

L110. Explain in detail how the gas measurements were made beyond the equipment used. Also, indicate the detection levels of the machine used (sensitivity).

L121. Why did you measure the color of the pulp? Usually, to register to ripen, you evaluate the background color; which part of the pulp was measured?

L127. The research describes equipment that measures compression/tension for firmness. how was it performed? since depending on the variety of peaches, they soften differently, at the shoulders, suture, or apex, please explain

L151. Please explain what the basis of the MI is

L160. ANOVA is described, but in the cases where only two treatments are mentioned in the t-test tables, please explain this situation.

L187. Please explain the results in fruit behavior; then, you can refer to general concepts. The results should be written, considering the effect on fruit physiology.

L214. Where is the evidence of fermentative metabolism?

L209. The concept of the peach as a climacteric fruit, or the analysis of this behavior, is entirely missing.

L234. Please combine tables 1 and 2 with Figs 1 and 2, since in some way they are redundant. 

 

Figure 1 is confusing; the different treatments’ bars seem to indicate that they were analyzed at other times; please correct them.

Table 1, why at 17 days the ES-R treatment was lost more weight?

 

L.504. The conclusion is incorrect; if UV had been used separately from KMnO4 and those results were compared with combined treatment, it could be mentioned that the effect was better or worse, but as it was not done, it is an unanswered question.

L511. What specific variable do the researchers base their findings on? “In addition, among the refrigerated treatments, a better performance was also observed, due to the presence of the ethylene scavengers. “

L512. Please remove “also highlight, although this was not the focus of our study, the need to complement the use of ethylene scavengers with humidifiers to control the relative humidity, to avoid excessive losses of weight and size in peaches subjected to refrigerated conditions,” The information has been known for a long time.

Author Response

Dear Editor and Reviewers,

 

We would like to express our sincere appreciation for the time and effort spent by the three reviewers in the evaluation of our manuscript titled “Combined effect of potassium permanganate and ultraviolet light as ethylene scavengers on post-harvest quality of peach at stressful and optimal temperatures” (agronomy-1587640). Thank you very much for your positive and constructive comments and suggestions, which are very helpful for the improvement of our paper. We have considered the comments carefully and have revised the manuscript thoroughly based on the comments. We deeply appreciate your work, and hope that the corrections and responses will meet with your approval. Revised portions are marked, in different colours depending on the reviewers, in the revised manuscript and the point-to point responses to the comments are listed below in this cover letter. In addition, to improve the quality of the English language, the manuscript has been sent to a native English person specialized in the correction of scientific articles and subsequently check by us. We look forward to your information about our revised paper.

Best regards,

Yours sincerely,

Dr. José Ramón Acosta Motos

 Reviewer 3. (GREEN)

L75. please provide harvest index of peaches

• Thank you very much for your suggestion. The harvest index (HI) defined as the classification of the fruit according to weight, size, firmness, total acidity (TA), soluble solids content (SSC) and SSC/TA ratio was carried out by the supplying company (Thader Cieza S.C.L.). The data obtained were as follows:
  • Weight: 179.5 g
  • Size: 72.0 mm
  • Firmness: 30.2 N
  • Soluble solids content (SSC): 10.9 %
  • Total acidity (TA): 3.8 %.
  • Ratio SSC/TA (MI): 2.86

The data has been added between lines 81 and 88.

L87. which is the relation of KMnO₄ / sepiolite? mol/g. How many grams per filter?

• The ratio of KMnO₄/sepiolite was 0.51 mmol/g. Each filter had a weight of 300g. It was not included in the article because we referred to the patent when describing the composition of the filters (No. 2548787, year 2016, Spain).

L96. How did the UV light impact the filters if these were covered by paper?

• Special thanks for your observation. As shown in the graphical abstract, the ultraviolet light does not hit the filters but the ethylene, on which it has an oxidative effect by photocatalysis. This complements the effect of potassium permanganate. Clarified in line 104.

L109. Explain in detail how the CCs were designed. L110. Explain in detail how the gas measurements were made beyond the equipment used. Also, indicate the detection levels of the machine used (sensitivity).

• Thank you very much for your suggestion. The CCs were acquired with temperature control incorporated, setting this parameter at 1 ºC. The mechanical structure for ethylene filter and UV light used in this study were specifically designed with a reduced size to be inserted into the CCs with the corresponding electrical connections. In addition, the CCs were equipped with a hermetically sealed probe in order to carry out the gas measurements without opening them and interfering with the preservation of the atmosphere, after that the fruit was extracted for the rest of the analyses. For these gas analyses, the Gas Analyser Felix Three F-950, Felix Instruments, Camas, WA, USA was used, with a sensitivity of 0.1 ppm for ethylene analysis, 0.01 % for CO₂ and 0.10 % for O₂. These parameters were then processed and expressed in the required units. It has been specified in lines 119-124.

L121. Why did you measure the color of the pulp? Usually, to register to ripen, you evaluate the background color; which part of the pulp was measured?

• Thank you in advance for your questions. No measurements were carried out on the skin of the fruit due to its chromatic heterogeneity. The variety chosen, "Rojo de rito", has red and orange areas without a clear pattern. Previous tests were made showing a huge variability, which masked the changes in ripening. Therefore, the colour of the pulp was measured immediately under the skin with a 2 mm cut in the equatorial zone. This measurement revealed that pulp colour changed differently during post-harvest ripening depending on the treatment. Line 130 has been rewritten in order to clarity this point.

L127. The research describes equipment that measures compression/tension for firmness. how was it performed? since depending on the variety of peaches, they soften differently, at the shoulders, suture, or apex, please explain

• Firmness measurements were carried out by compression as described in the materials and methods section. All measurements were made in the equatorial zone of the fruit, away from the suture, avoiding interaction with any anatomical part that would interfere with data acquisition. Clarified in line 137.

L151. Please explain what the basis of the MI is

• Thank you very much for your advice. The maturity index (MI) parameter is the ratio between the total soluble solids content (SSC) expressed in % and the titratable acidity or total acidity (TA) expressed in %. The MI determines the state of maturity of the fruit as described in the referenced bibliography. In this variety of peach and according to the producer, a MI of 3.4 or higher is considered an over-ripe fruit, it would be eatable but it wouldn't be at its optimum quality point.

L160. ANOVA is described, but in the cases where only two treatments are mentioned in the t-test tables, please explain this situation.

• Thank you very much for your comment. We have chosen the t-test in those cases where there were two treatments  because we thought it was more appropriate although for two treatments, the statistical interpretation of the ANOVA is the same. We have specified in the tables the statistical analysis carried out for each day of analysis.

L187. Please explain the results in fruit behavior; then, you can refer to general concepts. The results should be written, considering the effect on fruit physiology. L209. The concept of the peach as a climacteric fruit, or the analysis of this behavior, is entirely missing.

• Thank you very much for your suggestions. In order to improve the paper by introducing the reviewer's advice, we have added a section between lines 190 and 196 describing the physiological behaviour of peaches as a climacteric fruit.

L214. Where is the evidence of fermentative metabolism?

• In relation to this question, we consider the fermentative metabolism as an hypotheses to better explain the behaviour of the NoES-NoR treatment due to the lack of oxygen and the smell we appreciate from inside the CC for this treatment. In order to clarify our point of view we have rewritten this section to treat this as a hypothesis rather than evidence. Corrected in lines 252, 253 and 433.

L234. Please combine tables 1 and 2 with Figs 1 and 2, since in some way they are redundant. 

• Thank you very much for your suggestion. We are aware that the data in the tables and figures may seem redundant but the statistical analysis carried out on both elements differs. On the one hand, tables show the differences between the different treatments by day and parameter. On the other hand, figures show the differences between the measurements of the same parameter over time. After studying how to represent all data and the different statistical analysis, we considered that separating figures and tables was the most illustrative and least confusing way to do it.

Figure 1 is confusing; the different treatments’ bars seem to indicate that they were analysed at other times; please correct them.

• Special thanks for your suggestion. In order to improve the comprehensibility of the data shown in this figure, we have modified figure 1 completely, following the reviewer’s advice. Line type figure and logarithm scale have been used. Inserted between lines 201-220. Changes in figure 1 caption on lines 222-223.

Table 1, why at 17 days the ES-R treatment was lost more weight?

• This particular difference may be due to the variability of the fruit itself. For a more precise conclusion it would be necessary to observe the complete evolution of the parameter over time.

L.504. The conclusion is incorrect; if UV had been used separately from KMnO₄ and those results were compared with combined treatment, it could be mentioned that the effect was better or worse, but as it was not done, it is an unanswered question.

• Thank you very much for your suggestion. Indeed, such a conclusion can be confusing. We have modified the part where it appears in order to clarify what we want to communicate. Line 570 has been rewritten in order to clarity this point.

L511. What specific variable do the researchers base their findings on? “In addition, among the refrigerated treatments, a better performance was also observed, due to the presence of the ethylene scavengers. “

• Thank you for your enquiry. We have modified this section in order to clarify which variables we are referring to. Lines 576-578.

L512. Please remove “also highlight, although this was not the focus of our study, the need to complement the use of ethylene scavengers with humidifiers to control the relative humidity, to avoid excessive losses of weight and size in peaches subjected to refrigerated conditions,” The information has been known for a long time.

• Thank you very much for your suggestion. We have removed the highlighted section.