Phenolic Compounds from Pineapple Crown: Comparative Assessment of Fermentation and Conventional Extraction Methods

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors reported their review on Comparative assessment of fermentation and conventional extraction methods for Phenolic compounds from pineapple crown. The manuscript focused on biotechnology application for by-product processing which is in a high interest of bioeconomy

Abstract: Line 18-20 first two sentences should be transferred to the introduction section.

Line 25-26 should be transferred to the M&M section.

Overall, the abstract should be rewrite according to the journal requirements.

Keywords: Residue ? what does authors mean?

As feedstock for the experiments, different  extraction methods were used was used to answer the pineapple by-product processing to obtain value-added products, as it is a source of enzymes, organic acids antioxidants, and other nutrients. 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 a pineapple by-product in comparison with already organized technological process. The authors started to address this point in Line 114-122, but do not address this point in a sufficient manner 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.

Overall, the introduction section should be modified and focused on pineapple by-product processing and problems.

M&M: The authors stated: … They were placed in an air circulation oven at 60 °C for 48. The drying mode is very hard (temperature might damage a thermolabile compounds) And what was the necessity to dry for 48 hours? Why not to cut the material? Any explanations? What moisture value was obtained after drying?

Line 160: What does FRCA means?

Line 166-170: Any explanation of why suggested bacteria and the culture medium were choosen?

Statistical analysis?

Figure 1 is difficult to analyze – please change the type of the graph.

Figure 2 is a well-known information.

Figure 3 should be based on table type information of Chemical compounds and their values.

 

 

 

Based on the above points, and lacks in the experimental procedure as well in drying I would propose to rewrite and reconsider the manuscript.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The Authors described the recovery of phenolic compounds from pineapple using various methods. Their research aligns with the principles of the circular economy. However, in the Reviewer's opinion, the Authors' approach to the topic is superficial and requires a more thorough examination

Please read and adhere to the Author Guide.

Do the Authors work at the same University or at eight different universities?

Latin names should be italicized

„Pineapple processing generates an average of 60% of waste, including pits, bagasse, peel, and crowns, of which 76.4 million tons are leaf residues generated annually [27-30]. „ - Could the Authors clarify these information? Are there 76.4 million leaves alone? What percentage is that? How much other waste is there?"

What was the purpose of the study?"

Why was the sample dried at 60°C? This could also be considered a form of pretreatment. Did the Authors compare the results with samples dried, for example, at room temperature

What enzymes did the Authors study, and for what purpose

Did the Authors use standards for the substances being determined? Was the determination intended only for qualitative analysis? I n the Reviewer's opinion, a quantitative determination would be more scientifically and practically valuable. Having a standard curve for phenolic compounds allows for an easy calculation of their yield.

Why didn't the Authors provide data on the raw substrate? What was this substrate?

What is the purpose of Figure 2?

The Authors' observation regarding the similar phenolic compound content in samples subjected to maceration and Soxhlet treatment is strange, given that no phenolic compounds were detected in the HPLC analysis. How do the authors explain this? There is a brief explanation later—could it be more comprehensive and insightful?"

What other phenolic compounds might these be?

The Authors collected the material for analysis after the process was completed. Did Bacillus licheniformis consume or degrade the phenolic compounds?

In the Reviewer's opinion, it would be better to take samples on different days of fermentation, as this would provide a better understanding of the phenolic compound yield over time.

Why did the Authors choose the name Avicelase rather than the proper name -cellulose 1,4-β-cellobiosidase?

How do pectin-degrading enzymes promote the increased release of phenolic compounds? In the Reviewer's opinion, a broader discussion would be appropriate

In the Reviewer's opinion, it should be considered whether describing the effects of phenolic compounds on plants is necessary in the discussion.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

 

Line 40. Bromeliaceae must be written in italics.

All cultivar names must be placed in quotation marks; please check this throughout the entire manuscript.

Line 156. I recommend specifying the freezing and lyophilization parameters as well as the equipment used.

Line 153 and 159. You do not indicate the source number in square brackets.

You do not specify which statistical methods were applied. A section titled ‘Statistical Analysis’ is required.

The Results section is rather limited — are all the results really presented?

Review the list of references according to the requirements.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors reported their article on Comparative assessment of fermentation and conventional extraction methods for Phenolic compounds from pineapple crown. Several question the authors answered in current manner, however there is still a lack of data in the manuscript:

The abstract should include a numerical values of Phenolic compounds obtained by different extraction methods.

M&M: The authors stated: The supernatant was collected, frozen, and lyophilized (L101 Liotop) at -54°C with a pressure between 250 and 170 mmHg. However, pressure values between 250 and 170 mmHg are not in the range of lyophilization process!

The same issue in line 178-179.

Data from Table 2 is contractionary with fig 1. Does it mean that phenolic compounds obtained by Maceration are not identified by Shimadzu HPLC system?? Please provide the chemical profiles.

 

Based on the above points, and lacks in the experimental procedure as well in drying I would propose major revision of the manuscript.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

In the Reviewer's opinion, the Authors partially implemented the suggested changes in the manuscript. However, some comments remained unaddressed. In the Reviewer's opinion, a more extensive discussion would have been useful. If there are any literature data confirming or contradicting the Authors’ conclusions and observations, this should be noted in the responses. However, in the Reviewer's opinion, there are scientific studies on the yield of polyphenols from various agricultural substrates.

 

Ad 1.

Since the authors work at the same university, please indicate only one affiliation. There is no need to write it eight times.

 

Authors still do not use italics for Latin names.

 

Ad 3.

In the reviewer's opinion, the purpose of the work must be clearly stated in the manuscript.

 

Ad6

 In the reviewer's opinion, it would be advisable to present data on the raw substrate, before any processing. This would allow for comparison of yields, for example, of chemical compounds.

 

 Ad8

Where in the manuscript is this description found?

 

 Ad9.

How did the authors determine that there were no differences in the fermentation process when they only had initial and final data?

Typically, microorganisms behave differently with different forms of substrate.

 

Ad10.

Where in the manuscript is this explanation found? In the reviewer's opinion, the authors chose one of the less frequently used names.

Ad 11.

In the Reviewer's opinion, the names and explanations of the enzymes did not appear at the beginning, but rather later in the manuscript, which could have been misleading for readers.

 

Ad 13.

 In the Reviewer's opinion, the Authors' response does not explain why pectin-degrading enzymes promote increased release of phenolic compounds.

 

Why did the authors remove Figure 2?

Author Response

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Author Response File: Author Response.docx

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

The authors answered my question in current manner. The manuscript now can be accepted.

Author Response

Thank you for your contributions.

Reviewer 2 Report

Comments and Suggestions for Authors

In the Reviewer's opinion, the Authors corrected most of the suggestions, which improved the quality of the manuscript. However, in the case of a few comments, they have a different opinion, which is also understandable. The Authors may address these remarks if they find it appropriate; otherwise, the section may remain as it is.

Ad3

In the Reviewer's opinion, it would be advisable to present the yield of phenolic compounds before and after the three processes described. This would allow for a comparison of the efficiency of these three methods.

By "raw substrate" we mean the substrate before the process, not the substrate untreated by any pretreatment method.

Ad4.

In the Reviewer's opinion, it would be worthwhile to include at least two sentences describing the previous work and explaining why partial samples were not taken.

Author Response

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Author Response File: Author Response.pdf