The Correlation between Amino Acids and Biogenic Amines in Wines without Added Sulfur Dioxide

Round 1

Reviewer 1 Report (Previous Reviewer 2)

Comments and Suggestions for Authors

The authors have addressed my concerns adequately so I have no further objections. The paper can be accepted.

Author Response

Thank you very much for taking the time to review this manuscript.  

Reviewer 2 Report (Previous Reviewer 1)

Comments and Suggestions for Authors

In this article submitted by Sorin Macoviciuc et al., and entitled "Correlation between amino acids and biogenic amines at in wines without added sulfur dioxide", the author investigated the production of biogenic amines in vinification using sulfur dioxide as a preservative (+SO2) and methods without added sulfites (-SO2). While the study's findings are meaningful, there are some issues in this paper.

1. Line 115, the detailed information of Pichia kluyveriof, including its source and CFU per gram, should be provided.

2. Line 118, the information related to Pectolytic enzymes, including enzyme activity also should be given. Additionally, the information about Saccharomyces cerevisiae should be included in line 122.

3. The description from line 214 to 227, line 238 to 244, line 375 to 382, line 389 to 394, line 398 to 405, are recommended to be relocated to the discussion section.

4. The references to 21, 22, 24, 25, 26 and 34 in lines 268, 293, 307, 319, 330 and 425 are deemed invalid due to the fact that the descriptions provided in these sections are derived from data analysis.

5. The sensory evaluation of the wine produced employing different methods is suggested to supplemented.

6. The discussion should be revised to ensure a analysis of the data in depth is conducted. 

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections in the attached document. 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report (Previous Reviewer 1)

Comments and Suggestions for Authors

The article submitted by Sorin Macoviciuc, et al., and entitled "Correlation between amino acids and biogenic amines in wines without added Sulphur dioxide", was revised carefully by the authors following the review comments, the manuscript has been significantly improved. Therefore, I fully agree that this paper in its current state can be accepted.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

At present, alternative methods are being sought to replace sulphur dioxide in order to ensure low biological content and prevent oxidation reactions during wine fermentation. In this article submitted by Adel G. Abdel-Razek et al., and entitled "Correlation between amino acids and biogenic amines at wines without added Sulphur dioxide", the author utilized Pichia kluyveri for its ability to inhibit oxidation reactions, as well as malolactic fermentation for wines produced without the use of sulfur dioxide. The experimental design in this article, however, is overly simplistic and lacks depth. The study only focused on the distinctions between wine samples that contained sulphur dioxide and those that did not. Additionally, the language and the style of the manuscript need to be improved.

(1) The descriptions of Table 3, Figure 3, and Figure 4 should be included in the results section rather than the discussion section.

(2) The abstract and conclusion sections should be revised to provide a more concise and accurate summary of the main findings presented in the paper.

 

Other minor comments:

(1) “Vinification to dryness permitted formation of biogenic amines on low levels within normal limits, being 70.95 ppm for putresceine, 18.11 ppm tyramine, 6.12 ppm cadaverine, 9.26 ppm histamine and 31.32 ppm spermidine.” can be replaced with “Fermentation to dryness may result in the formation of biogenic amines at low levels within acceptable limits, with putrescine at 70.95 ppm, tyramine at 18.11 ppm, cadaverine at 6.12 ppm, histamine at 9.26 ppm and spermidine at 31.32 ppm.”

 (2) “Amino acids play a crucial role in wine making as they are present during fermentation processes, contributing significantly to the development of desirable aromas and characteristics.” can be instead of “Amino-acids are important in wine making because are present in fermentation processes important to achieve desirable aroma and characteristics.” 

(3) The unit of temperature of “OC” should be changed to “℃”, for example “ionization source temperature of 350OC “ should replaced with “ionization source temperature of 350 ℃”.

(4) “SO2” should  be  changed to “SO₂”. 

Comments on the Quality of English Language

English and manuscript writing must be significantly improved by the native speaker. There are many grammatical errors.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The study topic presented by the authors is interesting and is potentially publishable in Fermentation. However, as in my subsequent comments, I believe that the correlations (at least in some cases) are miscalculated, so the whole discussion and conclusions may be wrong. I have examined more closely some regressions that may not be statistically significant. Beyond the statistics, the dependence on the amine and amino acid levels seems reasonable in some cases.

Apart from correlations, the way to prove that the alternative (proposed) treatment can provide equivalent results to the conventional (SO2) one could be demonstrated better by ANOVA or paired t-tests.

Figure 1 is too big and should be reduced. I suggest including only a few representative examples to discuss in more detail. In any case, the figure needs to be improved. To avoid confusion, the indications a, b, c, etc. subplots should be inside the graph. The legends of the X and Y axes are not well defined. If I'm not wrong, they should be the concentrations of the amino acids (with the units in brackets) vs the concentrations of the amines (also with units in brackets). On the other hand, from the point of view of representativeness, supporting this discussion with only 4 points is very risky. In addition, the correlations include the regression bands, not explained at any time (or mentioned).

The comments on the results in Figure 1 are very tedious and repetitive (lines 168-261). I suggest that they could be organized by type of behavior. Also, as I mentioned, they are very tentative because the number of samples is very limited. Authors should advise these circumstances.

On the other hand, the results of the correlation coefficients and the significance of the correlation of the subplots in Figure 1 seem wrong to me. Although I do not have the original data, I have tried to estimate the x and y values ​​of each point from the graphs. For example, for subplot n, where the samples CS118, CS119, etc. appear, I have found a correlation of 0.8 and a p 0.2, with which the correlation is not significant (something similar could happen in other cases). If I'm right, I think you have to check all the other calculations and coherently redo the conclusions. If I'm not right, there's something I'm missing, that I can't understand. If so, the authors will have to explain better their data so that readers don't fall into the same mistakes.

Although it is not an analytical journal, the description of the experimental part is, in some cases, quite poor. There is a lack of data on the instrumentation used, the type of separation, etc. I understand that no derivatization is done so pristine analytes are separated and detected. An example chromatogram (of a sample) showing the MS traces of the different analytes would be welcome to show the quality of the separation.

The results of Table 3 are improperly expressed. If the ± is the standard deviation, this marks the number of significant figures. So 6.7±1.011 should be 7±1, 6.6±0.321 should be 6.6±0.3, or 13.4±0.071 should be 13.4X±0.07.

The PCA model should be global, with all the samples from all the classes, to see which wine features influence the distribution of the samples or the variables.

There are some curiosities, small errors, or ambiguities in the text. I mention a few by way of example:

Amine levels are quite high. For instance, is 70 mg L^-1 normal for putrescine?

Title: Sulphur should be not capital

Line 15.  “regală Frizzante. The Methods”. The point is missing.

Line 15. Pichia kluyveri itàlics. Please mention that is a yeast species. Also, italics for Saccharomices cerevisiae (L93), Oenococus Oeni (L96), etc. In general, check scientific names throughout the manuscript.

ppm is colloquial and ambiguous. It is better mg L-1.

SO2 when applies to the formula of the chemical compound should be SO₂.

Line 91. ^oC. Check throughout the document (e.g., lines 131-132, among others).

Line 116: Please correct “(HISand were purchased “

2.3. Chromatographic conditions; the analytical column and separation mode should be also specified here.

Line 145 and 146. amino acid (no hyphen) 

Line 155. Should be “Amino acid concentrations”.

 

Fig. 4. Biplot or loading plot?

Comments on the Quality of English Language

Formatting and grammatical errors should be checked.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The work entitled “Correlation between amino acids and biogenic amines at wines without added Sulphur dioxide” is not properly organized and it is very difficult to understand.

I do not think it has enough quality yet to be published on Fermentation. I make a series of observations to the authors for them to reflect on, with the aim of helping them improve their manuscript.

Title: I would suggest changing the preposition "at" to "in".

Abstract: The abstract has no logical structure. What is the relationship between sentence 1 and 2. Why were different methods evaluated in order to replace SO2? What are these methods? And what is the relation between SO2 and the formation of biogenic amines in wine? These ideas have to be clearly stated for the reader.

It remains to indicate the starting hypothesis (this is fundamental!!), why it is expected that vinifying with these methods will reduce the production of biogenic amines. What treatment was used as a control?

Line 13: Two types of wines? Which is the difference between them? At the end of the abstract, "samples with and without sulfur" are indicated. Are those the two types of wines made for each grape variety?

Line 15: Include a full stop after the word Frizzante.

The sentence beginning on line 15 must be rewritten. It's not understood.

Introduction:

In general, the wording of the manuscript is not clear, please check it carefully.

Line 40: All scientific names must appear in italics. Also in lines 59, 84, 93, 96… Please, revise it all along the text.

Line 57: “employ use” Please, correct the sentence.

Please, include the starting hypothesis, why it is expected that with the variation of different parameters during fermentation (please, clearly indicate those parameters) it can be possible to reduce the amount of biogenic amines formed. Missing context.

Materials and methods:

I would suggest that a scheme of the experimental development be carried out to facilitate the reader to better understand what types of vinifications were carried out and what variables were studied.

Lines 82-83: Please, include those parameters.

Line 84: What is the purpose of using Pichia kluyveri? Please, include this information.

Line 86: “instead for” Using this terms has no sense, what do you mean? Please revise the grammar.

Line 91: 20OC, please correct the units.

Lines 95-96:

In which cases is malolactic fermentation carried out simultaneously with the alcoholic one, for what purpose? Please improve this wording and be more clear when indicating the different treatments evaluated.

There is a lack of fundamental data to describe the fermentative process, inoculation dose, type of microorganism used, volume of must to ferment, among others. Please describe in such detail that the assay can be easily reproduced. How many replicates are made of each wine?

Line 140: This is the first time that this variable is introduced: different wine varieties. It should appear before, and clearly justified.

Lines 146-147: “samples that had up to 4 years.” What?? How can a sample hace up to 4 years? There are many missing information. The reader gets lots easily. Please, improve the wording of the text.

Sorry, it is quite complicated to understand the experimental design. I can not go further with the revision, since I did not understand the objective of the research, nor the variables considered and the hypothesis under study. Please, improve it before resending the manuscript again for further consideration.

Comments on the Quality of English Language

The text is very difficult to understand because of the way it is written and the way English is used. Please review it with a view to clarifying the ideas and providing the reader with as much information as possible so that he/she does not have to assume anything.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf