Optimization and Intensification of Bioactive Components and Antioxidant Activity of Extracts from Date Fruit (Phoenix dactylifera L.) Using Pulsed Electric Fields (PEF) Technology and Thermal Processing

Round 1

Reviewer 1 Report

The authors reported their work on application of PEF on intensification of bioactive components from Date Fruit. The organization of the manuscript is good. PEF technology and its application is a quite perspective topic.

1.     As feedstock for the experiments, PEF was used to enhance the extraction of polyphenols and antioxidant activity from downgraded date palm fruits. One of my initial concerns was whether it would be possible to accurately identify and pinpoint the current problem in industry of the necessity for PEF application in comparison with already organized technological process. The authors do not address this point in a sufficient manner in the Introduction, although they discuss about this in the Results and Discussion chapter. This will make the motivation for this experiment easier to understand in my opinion and introduce the reader better into the topic.

2.         Something else missed in the introduction section is to highlight the sources bio compounds from different parts of a  date palm fruits: skin, seed etc. Is there any difficulties with bio compounds extraction from skin or seed?

3.         Line 114: σd - totally electroporated substrate. How did authors measured this value? As further in the manuscript this value is quite important, the methodology should be clarified.

4.         R&D: The positive trend of temperature influence on bio compounds extraction efficiency was obtained. Why do authors did not increase the temperature up to 60 or 80? Any limits?

The same trend was observed for PEF intensity. Does extraction efficiency will increase with further electric field increasement?

 

 

Based on the above points, I would propose a minor revision of the manuscript.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The study aims to assess the impact of pulsed electric field treatment on the extraction of polyphenols and antioxidant activity from inferior date palm fruits. The results indicate the application of PEF can be an appropriate alternative treatment with the thermal processing in better extractability of phenoilc compounds with higher antioxidant potential.  However, major revision is recommended, questions and suggestions are as following.

1. The structure should be reorganized, some content should be put in the right sections or be deleted, such as line 73-75, line 201-205, line234-235, etc. Please check in the whole manuscript.

2. References are missing obviously in some paragraphs, for example, line 39-42.

3. Line 80, what water? gallic acid is different from that in line 84? ABTS^.+ is not right, it is prepared by the reaction of ABTS and potassium persulphate.

4.  Generally, more than 3 antioxidant assays should be applied to evaluate the antioxidant activity of samples. Only ABTS assay was adopted in this study, it’ s not enough. In addition, ABTS assay is to evaluate the scavenging free radical capacity, not the total antioxidant activity you mentioned in your manuscript, for example, line 147.

5. Line 182-183, the column temperature was maintained at 40 °C? are you sure to set column at this high temperature? Did you quantify the individual phenolic compound by HPLC-MS, or by HPLC? If the former was adopted, please specify the details for analysis.

6. Did you confirm the phenolic compositions by HPLC-MS. In addition, the phenolic chromatograms should be provided for visually displaying the differences or the intensification effects by using pulsed electric fields (PEF) technology and thermal processing.

7. Line 232, various substrates could be specified here.

8. Figure 2-4, the y-axis is unclear.

9. So many mistakes should be checked thoroughly, for example, letter case. blank  between two words. Please check in the whole manuscript.

10. gallic acid equivalents is generally abbreviated as GAE, please check in the whole manuscript.

11. Line 362, In the present results? I am confused with this expression.

12.  Most of the references cited in this manuscript are relatively old, Line 365-372, a new released paper could be cited here, DOI: 10.1016/j.lwt.2022.114308.

13. Some discussions are illogical, please check. For example, line 464-466, about the contribution of phenylanine ammonialyase (PAL) to the increase of phenolics and antioxidant activity.  

 

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Title: Optimization and intensification of bioactive components and antioxidant activity of extracts from Date Fruit (Phoenix dactylifera. L) using pulsed electric fields (PEF) technology and  thermal processing

Comments and suggestions for authors

Line no 14: Use “was” before the word “study”

Line no 24: Plz concise the sentence

Line no 33: Plz modify this sentence ,correct grammatical mistakes

Line no 36: Add the word “exhibt” before antioxidant

Line no 37. Please check these latest paper for the data relevant to date and disease management, Therapeutic potential of date palm against human infertility: A review. Metabolites, 11(6), 408.

Efficient utilization of date palm waste for the bioethanol production through Saccharomyces cerevisiae strain. Food Science and Nutrition, 9(4), 2066–2074.

Line no 42. Add reference for the statement.

Line no 48: What do you mean by “increasing” in this line.

Line no 48. pulsed

Line no 49: Plz shorten and link this sentence, this line is not understandable

Line no 48-51. No reference was quoted for PEF, you can check these great review article on PEF:

Electrical systems for pulsed electric field applications in food industry: An engineering perspective. Trends in Food Science and Technology, 104, 1-13

Pulsed electric field: A potential alternative towards a sustainable food processing. Trends in Food Science and Technology, 111(5), 43-54

Line no 54: Use the word “these” before pores

Line no 61: Plz use helping verb in this sentence

Line no 67: Plz use the word “thus”in place of “then”

Line no 91: Water used was HPLC graded

Line no 96: Plz use suitable word in place of “includes of”

Line no 138: Plz use the word “by” before applying

Line no 148: using ABTS assay in accordance with the method

Line no 192: Cut the word “to determine”

Plz use small letters for “treatment”, “temperature” and “antioxidant”

Line no 220: Plz modify this sentence

Line no 257: Plz change the word “bearable”

Line no 279: Plz use the word polyphenolic in place of polyphenol

Line no 294: This sentence is not grammatically correct

Line no 302: Modify this sentence

Line no 305:Don’t use the word “we”

Line 306: Plz modify. check for grammatical mistakes

Line no 310: change the word “enhance”

Line no 316: Don’t use the word “our”

Line 329: Change the word “afford”

Line 339: What do you mean by “several of components”

Line no 365: Change the word “announced”

Line no 369: Modify this sentence

Line no 372: Change the word “in our case”

Line no 381: Why orange and tomato is capitalized in this sentence?

Line no 387: Sentence is incomplete

Line no 388: Check for grammatical mistake

Line no 393: What do you mean by “expose”?

Line 398: What do you mean by “we finish”?

Line no 406: Change the word “touched”

Line 430: Change the word “in consequence”

Line no 432: Don’t use the word “our”

Line 442, 449: Plz modify

Line 472: Concise and modify the sentence

Line no 491: Check for grammatical mistakes

 Line no 493: Don’t use the word “our”

Line no 498: Change the word “attends”

Line no 501: Plz modify this sentence

Sentence making is not proper, and there is a usage of words, that are not suitable in scientific writing.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Thanks for improving the manuscript. This is absolutely a better manuscript than the previous one provided. However, some revisions did not respond well and need to be done before publication.

point 5, the authors did not clarify how to quantify the individual phenolic compounds. HPL-MS was used to identify the phenolics, or to determine the content of them?

point 6, I can not find the phenolic chromatograms.

point 8, it's still unclear.

point 12, the mentioned problem and the reference are not responded.

Author Response

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Author Response File: Author Response.docx