Prebiotic Activity of Poly- and Oligosaccharides Obtained from Plantago major L. Leaves

Round 1

Reviewer 1 Report

Manuscript ID: applsci-751829

Type of manuscript: Article

Title: Prebiotic activity of poly- and oligosaccharides obtained from Plantago major L. leaves

Authors: Paolina Lukova, Mariana Nikolova, Emmanuel Petit, Redouan Elboutachfaiti, Tonka Vasileva, Plamen Katsarov, Christine Gardarin, Guillaume Pierre, Philippe Michaud, Ilia Iliev *, Cédric Delattre

Although the overall approach is interesting, I do not recommend the acceptance of the paper presented in given form. Paper needs revision. In the following some comments are given which could be helpful for the improvement of the paper.

1. The authors did not performed any appropriate statistical analysis of the presented results. It is not possible to draw any conclusions without performing statistical analysis, at least Tuckey test and two-way analysis of variance (ANOVA).

• The authors need to be more accurate in the description of the results. The expression ‘a significant difference ’(Line 374) or ‘no significant difference’(Line 429) could be used only on the basis on the appropriate statistical analysis, which in this case was not performed.
• For Figures 5 and Table 1 : what are the numbers of replicates for the error bars?
• Table 2 and Figure 4 – there is no standard deviation included. How many replicates were performed for these assays?
• The results statistically different from the control, or from each other should be indicated in the tables and figures.

2. The authors shall explain the difference between the mass average molar mass (Mw) and number average molar mass (Mn), as well as its significance for structure anticipation.
3. The molecular weight of PWPs and PLM should be expressed in the same unit.
4. Line 251: Authors use the expression ‘depigmented polysaccharide’, which may not be very accurate, while the color parameters of polysaccharide were not determined in this work.
5. Line 336: ‘PLM had a long logarithmic rate phase of up to the 20th hour while PWPs was rapidly depleted by the 10th hour.’ – for L.sakei and L.brevis it seems to be depleted after 6^th hour?
6. Section 2.3. – please, give more details according to the method of neutral sugars and uronic acid determination.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer, please in attach file you can find our reply.

Author Response File: Author Response.docx

Reviewer 2 Report

This is a well-written and well-designed study. I have a few comments for the authors to consider:

1. Line 244: Which statistical tests exactly? Specify tests - main stat test and posthoc test.
2. Lines112-113: The drying process was carried out only overnight (24h) at room temperature (25 C). Was this enough to remove all the water content in the recovered precipitate? Why was lyophilization not used instead? Also was moisture content of the 'dried' samples measured, to make sure it is dry? Data on moisture content will affect % recovery which was indicated in line 253 to be at 19 g/kg (1.92%). Is this value based on dry weight of the precipitate?
3. Line 343 (Figure 4): I suggest for authors to run a suitable statistical analysis to determine significant differences among treatments over time for each probiotic studied, indicate the statistical results in the graphs and discuss it in the manuscript.
4. Line 363 (Table 3): Authors only indicate the initial pH values of PWP and PLM in lines 367-368. For presentation purposes, these data should be included in Table 3 in a way that readers could easily follow changes in pH as an effects of fermentation time relative to the initial pH. Also at what time was 'initial pH' obtained?Please indicate. After adding the initial pH values in Table 3, authors should run a statistical analysis and results should be indicated in the table in a way typically done for data like those contained in Table 3. Discuss statistical difference in the manuscript too.
5. Line 422: Same as my comments in No. 2 and 3 above, authors should run a statistical analysis of the data in Figure 4 and present results appropriately in the graphs. The values between 6h and 20 h accross all strains do not seem to be statistically significant. This needs to be verified by a statistical analysis and discussed. Discuss general statistical trends comparing to initial pH values in the manuscript too.

Minor comments:

1. Line 422: 'g' in α-galactose should be capital as it is the first word of the sentence.
2. Line 345: 'Proves for' can be changed to 'Evidence on'.
3. Line 168: MW, not Mw.
4. Line 74: What is meant by 'competitive" here? Is this the most appropriate word?
5. Line 108-109: 'with continuous stirring', not 'at continuous stirring'.

Author Response

Dear Reviewer, please in attach file you can find our reply.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Since Table 3, 5 and 6 contain statistical results, it could be presented as Supplementary Material.

I hope my review could help to improve the paper.

Author Response

Dear Reviewer, in attach file you can find our reply about your second review.

Author Response File: Author Response.docx

Reviewer 2 Report

The author responded well to the comments. I have one more comment for authors to consider:

I think that Tables 3 and 5 are important but do not necessarily have to be included in the main manuscript; instead, these tables can be included as supplementary information. BUT, statistical results from these tables can be indicated into the values in Table 4 and Figure 5, represented as letters (superscripts) or any other symbols put next to the values or above the bars to indicate significant difference (not forgetting to include captions below the table/figure).

Author Response

Dear reviewer, in attach file you can find our reply about your second review.

Author Response File: Author Response.pdf