Profiling of Phenolic Compounds of Fruit Peels of Different Ecotype Bananas Derived from Domestic and Imported Cultivars with Different Maturity

Round 1

Reviewer 1 Report

Discussion must be improved. No comparison of data, regarding the content of phenolic acids is provided, although there are some available works. This makes the work rather fragile

 

Reference 36 is missing from the text. 

 

I dont understand why SD in table 8 is presented separatly from mean values, as in all other tables.

Fig 2 is a repetition of data from table 6 and 7 and can be deleted

Author Response

Response to Reviewer 1 Comments

 

We were pleased to read the insightful evaluations of the reviewer 1.

1. Discussion must be improved. No comparison of data, regarding the content of phenolic acids is provided, although there are some available works. This makes the work rather fragile

Thanks for the reviewer’s advice. Following the suggestion, we have added data comparison on phenolic compound content in the ‘Results and Discussion’ section.

2. Reference 36 is missing from the text.

Thank the reviewer’s careful evaluation. Following the suggestion, we have added reference 36 in the text.

3. I dont understand why SD in table 8 is presented separatly from mean values, as in all other tables.

We apologize for this confusion. We have adjusted the data format in the table 8.

4. Fig 2 is a repetition of data from table 6 and 7 and can be deleted.

Thank you very much for this comment. We believe that the data in table 6 provides the solid data basis for the section ‘3.7.1. Quantitative analysis of main phenolic compounds in green banana peel’; the data in table 7 provides data support for the section ‘3.7.2. Quantitative analysis of main phenolic compounds in ripe banana peel’. Yet, Fig. 2 compares the contents of main phenolic compounds and total phenolic compounds between green peel and ripe peel of various banana cultivars and subgroups as a whole, which is very helpful for the overview and interpretation of part 3.7.3.

 

 

 

 

Sincerely and with our best regards,

 

 

Si-Jun Zheng on behalf of the co-authors

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors of this manuscript present an interesting research study on profiling of phenolic acids of fruit peels of different ecotype bananas derived from domestic and imported cultivars with different maturity. Introduction and the rest of the chapters are well described. However, the Discussion section is not separated form Results section. Please check the manuscript style according to the author’s instructions. The majority of the presented figures are clear. However, I wonder if the style of the figures is the most appropriate. The authors conclude the findings of their work. The text needs very few revisions. Although research studies on aquaponics have been studied in the past in different plant species, I believe that this study can add further research interest.

 

The first comment is about the style of the title. I think that the first letter from each word has to be capitalized. Please check the author’s instruction.

Furthermore, the sections except introduction have different style. (Check the distance between lines)

 

Abstract

COMMENT:

Line 20        Yet, it is a good source     please rephrase

Line 22        compelling information for making full use of them        please rephrase

Line 30        Analysis results showed that the phenolic           please rephrase

 

The Abstract describes sufficient the findings of this research work.

 

Introduction

 [2, 3].         Please do not leave gap between numbers fo ir [2,3]    check the text

 

Introduction section is well written and, in my opinion, give the appropriate information without being extended.

The aim and objectives of this study are clearly demonstrated.

 

Materials and Methods

Lines 112-113, 141-142, 219-220     please do not leave gap between the two lines. Check text

 

Results and Discussion

Dear author I wonder if the discussion section must be separated from the results section. Please check the author’s instructions

 

Discussion

The discussion section is included as one with the results. However, according to my opinion the authors did not discuss and compare the finding of their work with other similar research works.

   

Conclusions

Lines 408    Do not include references in conclusion section

According to my opinion conclusion section is extended. I suggest to limited in few lines.

 

References

COMMENT:

The References style looks like to be in accordance with the author’s instruction. However, please check the reference list according to the author’s instruction once again in order to be sure that is correctly typed and mentioned. Pages are missing in some reference for i.e. Check references 2, 5, 9, 21, 25, 33

 

In some references the first letter of the words is capitalized. Please correct it.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2 Comments

We were pleased to read the insightful evaluations of the reviewer 2.

1. The authors of this manuscript present an interesting research study on profiling of phenolic acids of fruit peels of different ecotype bananas derived from domestic and imported cultivars with different maturity. Introduction and the rest of the chapters are well described. However, the Discussion section is not separated form Results section. Please check the manuscript style according to the author’s instructions. The majority of the presented figures are clear. However, I wonder if the style of the figures is the most appropriate. The authors conclude the findings of their work. The text needs very few revisions. Although research studies on aquaponics have been studied in the past in different plant species, I believe that this study can add further research interest.

Thank you for your positive comments. We read the ‘Instructions for Authors’ of the magazine, it is mentioned that the discussion part can be combined with the result part (Please see the picture below for details). And all the style of figures in our article has been modified according to the revised requirements of the magazine.

2. The first comment is about the style of the title. I think that the first letter from each word has to be capitalized. Please check the author’s instruction.

We completely agree with the reviewer’s advice, we have modified the style of the title according to the Author's Instructions.

3. Furthermore, the sections except introduction have different style. (Check the distance between lines).

We fully agree with the reviewer's suggestion.  We have revised the style of each section according to the author's instructions, including the distance between lines.

4. Abstract

COMMENT:

Line 20        Yet, it is a good source     please rephrase

Line 22        compelling information for making full use of them        please rephrase

Line 30        Analysis results showed that the phenolic           please rephrase

Thank you very much for your comments. We have revised the three sections according to the wording comments in lines 20, 22 and 30 you mentioned.

The Abstract describes sufficient the findings of this research work.

Thank you for your affirmation on the Abstract section.

5. Introduction

 [2, 3].     Please do not leave gap between numbers fo ir [2,3]    check the text

We completely agree with the reviewer’s advice. We have deleted gaps where there are such problems in the article.

Introduction section is well written and, in my opinion, give the appropriate information without being extended.

The aim and objectives of this study are clearly demonstrated.

Thank you very much for your affirmation of the introduction. We have supplemented and provided appropriate information in the introduction without expansion. (Please refer to paragraphs 2-4 of the introduction for details)

6. Materials and Methods

Lines 112-113, 141-142, 219-220     please do not leave gap between the two lines. Check text

Thank you very much for this comment. We checked the text according to the reviewer's comments and deleted the gap between the two lines.

7. Resultsand Discussion

Dear author I wonder if the discussion section must be separated from the results section. Please check the author’s instructions

Thank you very much for your concern. We have read the ‘instructions for authors’ of the magazine. It is mentioned that the discussion part can be combined with the results part. (Please see the picture below for details)

8. Discussion

The discussion section is included as one with the results. However, according to my opinion the authors did not discuss and compare the finding of their work with other similar research works.

Thanks the reviewer’s comments. In revised version we have discussed and compared the findings of our work with other similar research works in the 3.1, 3.3, 3.7, 3.8 section of the Results and Discussion.

9. Conclusions

Lines 408    Do not include references in conclusion section

We completely agree with the reviewer’s advice. We have deleted the references in the conclusion.

According to my opinion conclusion section is extended. I suggest to limited in few lines.

Thank you very much for this nice comment. We have simplified the content of the conclusion.

10. References

The References style looks like to be in accordance with the author’s instruction. However, please check the reference list according to the author’s instruction once again in order to be sure that is correctly typed and mentioned. Pages are missing in some reference for i.e. Check references 2, 5, 9, 21, 25, 33

In some references the first letter of the words is capitalized. Please correct it.

We apologize for some mistakes, and we have researched the documents 2, 5, and 9 and found that the information of the actual documents was incomplete, so we replaced them with new documents. Now, we have checked the format of all references according to the author's instructions and modified the page number and letter case format according to the suggestions. Since we deleted part of the content in the introduction part and added new content, the discussion part also added new content, and at the same time cited new documents, so compared with the previous articles, the order and quantity of the overall literature are changed. Thank you very much for your kind reminder.

 

 

 

 

 

Sincerely and with our best regards,

 

 

Si-Jun Zheng on behalf of the co-authors

Author Response File: Author Response.pdf

Reviewer 3 Report

see attached review

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 3 Comments

 

We were pleased to read the insightful evaluations of the reviewer 3.

 

The authors present interesting results on 8 phenolic compounds in fruit peels of 10 banana ecotypes. They used UPLC-MS/MS for analysis. Thus, the authors present interesting results with impact on scientists as well as on industry.

Thank you very much for this positive comment.

However, there are some points to be corrected to improve the quality of the manuscript:

1. Line 28: please give all values only with one digit after decimal point

We have modified the number format you pointed out, checked the full text, and modified the numbers as you suggested in the article.

2. Line 29: three of the keywords are already mentioned in the title; please look for alternatives

Thank you very much for your nice suggestions. We have replaced the keywords mentioned in the title with other words.

3. Lines 127-130: please give the column temperature, being important for the chromatographic separation

We completely agree with the reviewer’s advice, and the column temperature of 35 ℃ has been given in the article. Thank you very much for your reminder.

4. Line 159: please change “placed it in” into “placed in”

Thank you very much for your suggestion. We have revised it as required in the Line 159.

5. Line 162: what is meant with “toke”? Did you mean “took”?

Thank you very much for your comments. Sorry, it's a writing error when we wrote the article, it does mean“took”, and now we have revised it in the article.

6. Line 171: please insert a comma after “Then”

We completely agree with the reviewer’s advice. We have inserted a comma after “Then” in the line 171.

7. Line 233: please change “were shown” into “are shown”

Thank you very much for your suggestion. We have revised it as required in the Line 233.

8. Lines 274/275: please give all values only with one digit after decimal point

We completely agree with the reviewer’s advice. We have modified the number format as required in the line 274/275.

9. Table 4: please give values for average recovery, standard deviation and RSD only with one digit after decimal point

We completely agree with the reviewer’s advice. And we have revised the number style as required in the table 4.

10. Lines 299-301: please give all values only with one digit after decimal point

We completely agree with the reviewer’s advice. We have modified the number style as required in the line 299-301.

11. Line 360: please change “among the all banana” into “Among all banana”

Thank you very much for your comments, and we have revised it according to your suggestion in the line 360.

 

 

 

Sincerely and with our best regards,

 

 

Si-Jun Zheng on behalf of the co-authors

Author Response File: Author Response.pdf

Reviewer 4 Report

General comments

The present manuscript “Profiling of Phenolic Acids of Fruit Peels of Different Ecotype Bananas Derived from Domestic and Imported Cultivars with Different Maturity” is about taking advantage of food wastes as sources of value-add compounds such as phenolics. In this sense, banana by-products were evaluated regarding their abundancy on phenolic acids according to their maturity stage and cultivars.

It is always a pleasure to see works aiming the biomass valorisation through non-competitive mechanisms, namely the food industry.

This manuscript showed enough quality regarding its content. Nevertheless, the written presentation/quality needs to be revised along with the paper.

Also, it would be great if the authors read some papers about the extraction of phenolics from natural products to re-organize the presentation of their results.

Abstract

The main aim of the study is well presented. However, despite the importance of the developed LC-MS method and, the scope of this journal, it is important to endorse the main achievements regarding the phenolic profile and abundance of banana peels. Therefore, in my opinion, it would be better if the authors redacted this section.

Introduction

Lines 50-52: interesting paragraph, however, it would be great if further info is presented. Why those works are studying/proposing banana peels for the mentioned applications? Which are the main properties to contribute to those applications?

Line 55 suggestion: (…) biological and pharmacological properties with potential as antimutagenic, (…) agents, as well as a food additive (…).

Line 60: (…) antioxidant. ?? potential? Properties? Do the authors want to say, “Widely recognised due to their antioxidant effects”?

Line 66: direct boiling. Do the authors want to mention the decoction extraction method?

Line 67: compression. Do the authors want to mention the extrusion extraction method?

It would be great if the authors consider redacting this section, especially this paragraph (L 66-83). Suggestion: UAE is one of the emergent techniques of extraction used to reduce time and solvent in extraction procedures. Also, UPLC-MS-MS have been widely applied for the characterization and quantification of phenolics obtained from foods and their by-products.

Materials and Methods

Line 103: De-ionized?

If this work is about phenolic acids, why do the authors are mentioning rutin as a standard? If the samples presented rutin and catechin, therefore you must change the title of this manuscript as well as presenting the most abundant compounds found in the abstract section.

How were the extracts analysed? As obtained or dried?

Results and Discussion

Table 1. Please add Refs in this table to support the fragmentation pattern of those phenolics, please.

Line 239: extract yields instead of recoveries as this is not about separation or purification procedures.

What is “extraction frequencies”? New solvent added? The number of UAE impulses? Please explain what it does means.

Line 245: “volume fraction acetonitrile” could be better perceived if presented as “acetonitrile concentration”. The concentration of ACN in what? Water? Methanol?...

Tables 4 and 5, if no info for the Caffeic acid, why present no filled lines?

Lines 305-308: delete. You only need to mention in the results section that “traces of caffeic acid were detected but in very low amounts, therefore they were not quantified”.

Section 3.5: please rephrase the last sentence, it is confusing.

Line 312: “DW” the authors do not explain what DW means. Dry weight is about the dried material or dry extract?

Table 6: it could be better for the readers if the authors add the total amount of phenolics to this table.

This work is about phenolic compounds and not phenolic acids despite phenolic acids being the most abundant fraction obtained, especially due to the contribution of quinic acid concentration. This is the highest conclusion you have, and it is not evident in your discussion, abstract or conclusions.

Conclusions

It is not supposed to use Refs in this section as it is for conclusions and not for discussion.

Finally, please remove SI info from the main manuscript.

Author Response

Response to Reviewer 4 Comments

We were pleased to read the insightful evaluations of the reviewer 4.

 

1. General comments

The present manuscript “Profiling of Phenolic Acids of Fruit Peels of Different Ecotype Bananas Derived from Domestic and Imported Cultivars with Different Maturity” is about taking advantage of food wastes as sources of value-add compounds such as phenolics. In this sense, banana by-products were evaluated regarding their abundancy on phenolic acids according to their maturity stage and cultivars.

It is always a pleasure to see works aiming the biomass valorisation through non-competitive mechanisms, namely the food industry.

Many thanks reviewer for your positive comments.

This manuscript showed enough quality regarding its content. Nevertheless, the written presentation/quality needs to be revised along with the paper.

Also, it would be great if the authors read some papers about the extraction of phenolics from natural products to re-organize the presentation of their results.

Thanks for your suggestions and we have read some literatures on the extraction of phenolics from natural products, rewrote our ‘Results and Discussion’ part and added relevance references (References 16, 38-46).

 

2. Abstract

The main aim of the study is well presented. However, despite the importance of the developed LC-MS method and, the scope of this journal, it is important to endorse the main achievements regarding the phenolic profile and abundance of banana peels. Therefore, in my opinion, it would be better if the authors redacted this section.

We completely agree with your advice. We have revised the abstract according to the main achievement direction of recognizing the phenolic components and abundance of banana peels.

 

3. Introduction

Lines 50-52: interesting paragraph, however, it would be great if further info is presented. Why those works are studying/proposing banana peels for the mentioned applications? Which are the main properties to contribute to those applications?

Thank you very much for this comment. We have added relevant literatures (literature 7-11) and supplemented this part. We think banana peel, as agricultural waste, contains a large number of oligosaccharides, cellulose and mineral elements, which is an ideal material for adsorbents and is widely used to reduce environmental pollutants, such as heavy metals, dyes, organic pollutants, nitrate and arsenate in groundwater, pesticides and various other gaseous pollutants. And at present, banana peel has recently been increasingly reported as a rich source of phenolic compounds, with total phenolic content ranging from 4.95 to 47 mg garlic acid equivalent/g dry matter (mg GAE/g DM). This level was 1.5-3 times higher than that recorded in the pulp.

Line 55 suggestion: (…) biological and pharmacological properties with potential as antimutagenic, (…) agents, as well as a food additive (…).

Thank you very much for this comment. We have modified it according to your suggestion.

Line 60: (…) antioxidant. ?? potential? Properties? Do the authors want to say, “Widely recognised due to their antioxidant effects”?

We completely agree with the reviewer’s advice. Yes, we want to express that banana peel has strong antioxidant activity because it is rich in phenolic compounds. It is widely recognized and used because of its antioxidant effect. And we also modified the expression in this part to make people more clearly understand the meaning of the article.

Line 66: direct boiling. Do the authors want to mention the decoction extraction method?

Line 67: compression. Do the authors want to mention the extrusion extraction method?

We completely agree with the reviewer’s advice. This is a list of the existing techniques for extracting phenolic compounds from fruit peel. Direct boiling is the extraction method of decoction. Compression is represented by extrusion extraction. We have modified the description of this extraction technology.

It would be great if the authors consider redacting this section, especially this paragraph (L 66-83). Suggestion: UAE is one of the emergent techniques of extraction used to reduce time and solvent in extraction procedures. Also, UPLC-MS-MS have been widely applied for the characterization and quantification of phenolics obtained from foods and their by-products.

Thank you very much for this comment. UPLC-MS-MS has indeed been widely used in the characterization and quantification of phenolic compounds obtained from food and its by-products. According to the comments of the reviewer, we rewrite the introduction, especially line 66-83, and shift the focus from the establishment method to the discussion of the composition and abundance of phenolic compounds in banana peel.

 

4. Materials and Methods

Line 103: De-ionized?

We apologize for the confusion. It should be Deionized water.

If this work is about phenolic acids, why do the authors are mentioning rutin as a standard? If the samples presented rutin and catechin, therefore you must change the title of this manuscript as well as presenting the most abundant compounds found in the abstract section.

We apologize for the confusion. Phenolic Compounds include phenols and phenolic acid, flavonoids, anthocyanins and tannins. Rutin and Catechin belong to flavonoids and the other six substances belong to phenolic acids. Therefore, our whole article is to analyze the composition and content of phenolic compounds in pericarp. We replace phenolic acids with phenolic compounds. At the same time, we also show the most abundant compounds we found in the abstract.

How were the extracts analysed? As obtained or dried?

Thank you very much for this comment. We use a sensitive and reliable analytical method - Ultra-high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry for measuring phenolic compounds in fruit peel from different ecotype cultivars and subgroups with different maturity. The screened banana peel powder was extracted by acetonitrile, centrifuged and detected on the film. The components of the extract were analyzed by mass spectrometry and liquid phase quantitative detection. The obtained banana peel powder was dried.

 

5. Results and Discussion

Table 1. Please add Refs in this table to support the fragmentation pattern of those phenolics, please.

Thank you very much for this comment. We have added reference 33 in Table 1 to support the fragmentation patterns of these phenolic compounds.

Line 239: extract yields instead of recoveries as this is not about separation or purification procedures.

We completely agree with the reviewer’s advice. We have changed our wording on line 239.

What is “extraction frequencies”? New solvent added? The number of UAE impulses? Please explain what it does means.

Thank you very much for this comment. We apologize for the confusion. “Extraction frequencies” means that ‘the number of extraction’. “New solvent added” means that solvent acetonitrile for extracting phenolic compounds from Peel. “The number of UAE impulses” means that ultrasonic power.

Line 245: “volume fraction acetonitrile” could be better perceived if presented as “acetonitrile concentration”. The concentration of ACN in what? Water? Methanol?...

We completely agree with the reviewer’s advice. Methanol and acetonitrile were purchased from Fisher Scientific (Loughborough, UK). The concentration of acetonitrile is 99.95% of HPLC grade, the concentration of methanol is 99.95% of HPLC grade, and the water is deionized water.

Tables 4 and 5, if no info for the Caffeic acid, why present no filled lines?

Thank you very much for this comment. Caffeic acid content in the banana peel was lower than the detection limit of the instrument. Therefore, it could not be detected in the banana peel. In Table 4 and table 5, we use a slash to indicate that the content of caffeic acid is very low and cannot be measured.

Lines 305-308: delete. You only need to mention in the results section that “traces of caffeic acid were detected but in very low amounts, therefore they were not quantified”.

Thank you very much for this comment. We have revised and wrote in the results section that "trace caffeic acid was detected, but the content was very low, so it was not quantified".

Section 3.5: please rephrase the last sentence, it is confusing.

We apologize for the confusion, and we have restated this part.

Line 312: “DW” the authors do not explain what DW means. Dry weight is about the dried material or dry extract?

We apologize for the confusion. DW means ‘Dry weight is about the dried material’.

Table 6: it could be better for the readers if the authors add the total amount of phenolics to this table.

We completely agree with the reviewer’s advice. We have added the total amount of phenolic compounds to the tables 6 and 7.

This work is about phenolic compounds and not phenolic acids despite phenolic acids being the most abundant fraction obtained, especially due to the contribution of quinic acid concentration. This is the highest conclusion you have, and it is not evident in your discussion, abstract or conclusions.

We completely agree with the reviewer’s advice. We have changed the phenolic acid in this article into phenolic compounds. Phenolic acids are only a part of phenolic compounds; and in the abstract, discussion and conclusion. Also, we highlight the key component-quinic acid result of this study, and focus on it.

 

6. Conclusions

It is not supposed to use Refs in this section as it is for conclusions and not for discussion.

We completely agree with the reviewer’s advice. We have deleted the references in the conclusion.

Finally, please remove SI info from the main manuscript.

Thank you very much for your suggestions, and we have removed this part from main manuscript as required and put them separately into supplementary materials.

 

 

 

 

Sincerely and with our best regards,

 

Si-Jun Zheng on behalf of the co-authors

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Accept in present form

Author Response

Response to Reviewer 1 Comments

 

Comments and Suggestions for Authors: Accept in present form.

 

Many thanks the reviewer 1 for your positive comments.

 

 

 

Sincerely and with our best regards,

 

Si-Jun Zheng on behalf of the co-authors

 

Reviewer 4 Report

The authors greatly addressed the previous suggestions, improving the quality of their manuscript.

The only further suggestion, and related to the previous comments, is to add "<LOQ" for the caffeic acid case (Table 4). Therefore it is fully perceptible that traces were found but lower than LOQ.

Author Response

Response to Reviewer 4 Comments

We were pleased to read again the insightful evaluations of the reviewer 4.

The authors greatly addressed the previous suggestions, improving the quality of their manuscript.

Many thanks the reviewer for your positive comments.

The only further suggestion, and related to the previous comments, is to add "<LOQ" for the caffeic acid case (Table 4). Therefore it is fully perceptible that traces were found but lower than LOQ.

Thank you very much for this comment. We completely agree with your further suggestion. We have added "<LOQ" for the caffeic acid case in the Table 4. In this way, it could be seen that traces were found, but lower than LOQ.

 

 

 

Sincerely and with our best regards,

 

Si-Jun Zheng on behalf of the co-authors