Naturally Fermented Gordal and Manzanilla Green Table Olives: Effect of Single Yeast Starters on Fermentation and Final Characteristics of the Products

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper is interesting but the most interesting part of this work, the relationship between total phenol content and perceived bitterness intensity, is not well developed.

The authors first state that “However, to our knowledge, the relationship between 104 total phenol content and bitterness intensity has not been investigated in table olives. (line 104-105)”, then, in Materials and Methods section 2.2.7, they say that in a previous work (which?) were analyzed some samples of table olives for total phenol content and perceived bitterness intensity. The authors should explain in detail what they are referring to and cite the previous work (line 221). It is not clear whether the bitterness perceived is the bitterness perceived through sensory analysis or not. In FigS4 there are 9 points of bitterness intensity but it is not specified where they come from (sensory analysis? Other?). However, this seems to contradict what is stated in the Abstract that this predictive model “providing a simple and objective method for the evaluation of bitterness in table olives without the need for sensory analysis.”

I recommended the publication after major revisions.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This study provides a simple and objective approach to evaluate the bitterness of table olives without the need for organoleptic analyses. And some contents need to improve.

1.Figures 2 and 3 are blurry, pixels need to be upgraded

2.Abstract is doesn't summarise the whole text very well, needs to be improved

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript discusses the production and final characteristics of fermented beverages obtained by fermentation of natural-style Gordal and Manzanilla green table olives with single yeast starters (Kluyveromyces lactis L39, Kazachstania humilis AG5, 9 Nakazawaea molendinolei IG9, Candida diddensiae IG12, and Candida adriatica L30).

While the paper may be of high interest to readers, it has several shortcomings as outlined below. Therefore, it should be thoroughly revised by all authors before being considered for publication in Fermentation.

 

Other considerations are as follows:

Abstract section

1. Page 1, Lines 19-22: This statement is incorrect. Please refer to comment 3.4 in this letter for clarification.

 

1. Introduction section

This section should be rewritten to eliminate excessive information unrelated to the paper's main issue.

1.1. Page 2, Lines 75-76: Change “L. plantarum and Lactobacillus pentosus” to “Lactobacillus plantarum and L. pentosus”.

 

2. Materials and methods section

2.1. Page 3, Lines 142-143: Why were all fermentations performed at ambient temperature (between 8 °C and 22 °C)? Why were the fermentations not conducted at a fixed temperature? This variable is known to have a significant effect on the growth and product formation of yeasts.

2.2. Page 3, Line 146:  Why were the inoculations performed after 7 and 20 days of brining?

 

3. Results and discussion section

3.1. Page 10, Figure 2: This figure needs improvement.

3.2. Page 11, Figure 3: This figure needs improvement.

3.3. Pages 7 and 12: In Tables 1 and 2, different font types were used. Please use a consistent font type for both tables.

3.4. Pages 15, lines 524-535: I think the obtained prediction model cannot be used to successfully estimate the bitterness of natural-style Gordal and Manzanilla table olives without any sensory evaluation. This is because the model only explains 81.5% of the total variability observed in the experimental data, leaving 18.5% unexplained. In fact, Figure S4 shows that the relationship between the mean intensity of perceived bitterness and the total phenol content in 44 samples of natural-style Gordal and Manzanilla table olives is not linear. The majority of the experimental points deviate from the calculated line (Bitterness intensity = 0.001TP - 0.871). Additionally, Figure 6 shows significant differences between measured and predicted bitterness intensity in uninoculated and inoculated samples of natural-style Gordal and Manzanilla green table olives.

 

5. Conclusion section

Given the methodological and interpretation errors identified in the paper, the conclusions drawn by the authors lack support from the obtained results. Additionally, this section redundantly presents the results without clear conclusions.

5.1. Page 10, Lines 554-557: This sentence repeats the results (page 15, lines 526-527, and lines 538-539) rather than providing a correct conclusion. Please rewrite it to offer an appropriate conclusion based on the correct analysis of the relationship between the mean intensity of perceived bitterness and the total phenol content in the samples.

 

6. References section

According to the Instructions for Authors on the journal's website, “references must be numbered in order of appearance in the text (including table captions and figure legends) and listed individually at the end of the manuscript. In the text, reference numbers should be placed in square brackets, and placed before the punctuation; for example [1], [1–3] or [1,3]. For embedded citations in the text with pagination, use both parentheses and brackets to indicate the reference number and page numbers; for example [5] (p. 10). or [6] (pp. 101–105).”

However, the authors did not adhere to these guidelines, as the references were not numbered in the order of their appearance in the text.

Author Response

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Author Response File: Author Response.docx