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Message from the Peer Reviewer
Thank you for choosing Enago to assist you in peer reviewing. We have carefully reviewed yourmanuscript and have performed a comprehensive evaluation of your manuscript. Based on thisevaluation, we have prepared this report that gives you an assessment of your paper, along with alist of problem areas and suggested revisions organized in an order of priority, to minimize chancesof journal rejection.

Enago | Disclaimer: This report was compiled by our Peer Review Expert(s) after careful consideration of yourmanuscript considering several parameters. The author(s) should read the report carefully and address the reviewer’scomments in his manuscript before choosing a journal. This report is based on our expert’s assessment of themanuscript and should not be considered as a guarantee of manuscript acceptance in the journal.

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Manuscript Details
Assignment CodeABCDE-1

Total Word Count

4206

Manuscript Title-------------------------------------------------------------------------------------------------

Journal URL

http://www.journals.elsevier.com/archives-of-oral-biology/

Detailed Review of Each Section
Title Page
The title is concise and accurately conveys the principle content of the document. No contact details or affiliations
are provided. Please make sure that a contact email address is added to the title page along with the affiliation of
the author.
Abstract
Abstract: The abstract is not structured, but you still have to present these 4 sections:
1) Background:
After the text:
Add the goal of the paper:“The most efficient method to produce L-cysteine is whole-cell assays using Pseudomonas strains, which isproblematic given the infectious nature of these bacteria. ---------------------------------------------------------------------------------------------------------------------------”
2) Methods.
You forgot to include the Method section:“The metabolites of γ-EC were identified by HPLC analysis following thermal treatment of purified compounds andyeast extract.”
3) Results.
To indicate where the Results section begins, write:“Results show that purified γ-EC was almost completed converted into L-cysteine in 2h by thermal treatment
under acidic conditions (90°C; pH 5.0). Thermal treatment of yeast extract also supported the liberation of Lcysteine from γ-EC. Investigation of the mechanisms supporting this conversion supports primarily a two-stepprocess...”Do not describe all possible pathways. This is an Abstract. Stick to the major findings.
4) Conclusion“This study suggests that the thermal treatment of a yeast strain overproducing γ-EC may constitute a newmechanism to generate L-cysteine for the food industry.
Introduction
General statement:
We understand the comments of the reviewers very well. Most of the text is a list of foodstuff applications forcysteine, while you devote little time to explain the rationale and problematic to justify your study. Given the

Enago | Disclaimer: This report was compiled by our Peer Review Expert(s) after careful consideration of yourmanuscript considering several parameters. The author(s) should read the report carefully and address thereviewer’s comments in his manuscript before choosing a journal. This report is based on our expert’s assessmentof the manuscript and should not be considered as a guarantee of manuscript acceptance in the journal.

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critical importance of this section, we devoted considerable time to show you how to improve the text in terms offocus and impact.
Suggestions:
Here is the general structure of an Introduction:
1) First Paragraph: Introduce the importance of cysteine in the food industry. Reduce this paragraph by ½.
Remember, this is not a review of literature.
As a general guideline, here is our suggestion:“L-Cysteine, one of the 20 natural amino acids, plays important roles in foodstuffs, with respect to food texture,color and flavor. For example, L-cysteine improves the rheological properties of bread, crackers, and cookies(Narpinder and others 2002; Bollain and Collar 2004) by reducing disulfide bonds in the dough, which relaxes
gluten interactions (Bloksma and others 1990). In fruit juices, L-cysteine prevents browning of the product (Skalski
and Sistrunk 1974; Montogmery 1983) and preserves flavor during storage (Naim and others 1993a, 1993b). As
new applications are continuously emerging for L-cysteine in the food industry (Starkenmann et al. 2008), thedevelopment of efficient production methods is becoming a priority.”
2) Second Paragraph: Explains the importance of your study by explaining the current problem with L-cysteine
production for food products. Consult the Introduction of this article as a source:
Huang Y. Et al. 2011. Optimization of enzyme-producing conditions of micrococcus sp. S-11 for L-cysteine
production. African J. Biotechnol. 10(4): 615-623(http://www.academicjournals.org/AJB/PDF/pdf2011/24Jan/Huang%20et%20al.pdf)
We suggest content along this line:“Currently, four methods are being used to produce L-cysteine: hair hydrolysis (Hee et al., 1997), microbe
fermentation, chemical synthesis (Maier and Winterhalter, 2001) and bioconversion of 2-amino-2-thiazoline-4carboxylic acid by whole-cell catalysis (Sano and Mrrsugi, 1978). While the latter technique is favored for its highyield and low energy requirements, most bacterial strains belong to the highly infectious Pseudomonas family(Hiroshi et al., 2002). For this reason, considerable effort is currently deployed to identify other high-yield sourcesof L-cysteine. “
3) Third paragraph: Explains the rationale of your study, which is essentially why the approach that you use tosolve the problem is justified and plausible.
“We recently isolated a strain of yeast (Saccharomyces cerevisiae haploid strain Nα3) that accumulates γglutamylcysteine (γ-EC) (Nishiuchi et al., 2010), which is a precursor of L-cysteine (Ristoff and Larrson, 2007). ----------------------------------------------------------------------------In the present study, we tested the hypothesis that γ-EC is the metabolic source of L-cysteine in yeast extract, andthat a strain which accumulates this precursor could represent a safe and high yield alternative to Pseudomonasderived sources of the amino acid.”
Ristoff E. & Larrson A. 2007. Inborn errors in the metabolism of glutathione. Orphanet J Rare Dis. 2: 16.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1852094/pdf/1750-1172-2-16.pdf
Methods
General Guideline:
Start each paragraph by explaining why you are doing this.
Also, the sections are not in a comprehensive order. We suggest the following:
A - Chemicals
B - Thermal degradation of each compound
1) Start the text with a statement to explain why you did this.
Justify the list of metabolites. Why did you decide to detect these molecules? Are they abundant proteins in yeast?
Your HPLC profiles do not show most of them.
Enago | Disclaimer: This report was compiled by our Peer Review Expert(s) after careful consideration of yourmanuscript considering several parameters. The author(s) should read the report carefully and address thereviewer’s comments in his manuscript before choosing a journal. This report is based on our expert’s assessmentof the manuscript and should not be considered as a guarantee of manuscript acceptance in the journal.

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2) Justify why you used a wide range of pH (3.0 to 7.0). Is it to represent the various pH conditions that would be
encountered in yeast and food?
3) Justify 90ºC and pH 5.0. Are these the conditions used in the study “Munch et al. 1997”?
4) If this is the case, mention it here and add the reference. This will reassure the reviewers that you chose valid
conditions for your study.
C - Measurements of cysteine, α-EC, γ-EC, and PyrCys contents
1) This first sentence would clarify your intentions:“The concentrations of L-cysteine, α-EC, β-EC, and PyrCys derived from ABD-F were determined by derivatizationof the samples, followed by HPLC analysis as we previously reported (Nishiuchi and others 2011a, 2011b).”2) Since you already published the HPLC method, do not give details. Only mention what is not in your previous
papers. You need to remove the rest of the text, so that the above sentence is all that you have in this section.
D - Dynamics of γ-EC in yeast extract
1) Again, start by reminding us why you do this.
2) “Experiments were conducted to test whether heat degrades γ-EC into L-cysteine in the yeast strain we
identified as a rich source of this precursor (Nishiuchi et al. 2010). “
Question: In your description of the culture protocol for yeast, what was the pH of the culture medium? Was it
different than 5.0? ”
3) Clarify your protocol because you use 2 different incubation temperatures. Does thistext makes sense?
“The cell suspension was heated at 70°C for 10 min to cause lysis, and the yeast extract was collected bycentrifugation. The supernatant was adjusted to pH 5.0 with 1N HCl, and heated at 90°C for up to 4h (not 1h) to
determine the impact of heating on γ-EC metabolism”.
4) Question: Justify 90°C and pH 5.0. Are these the conditions used in the study “Munch et al., 1997”? If this is
the case, mention it here and add the reference. This will reassure the reviewers that you chose valid
conditions for your study.
5) Finish the last sentence by specifying the method of analysis:“...cooled, the samples were analyzed by HPLC.”
Conclusion: By now, you should understand that your use of a range of pH (3.0-7.0) to analyze the metabolites is
confusing during the entire paper. Justify!
G - Statistical Analysis
Add that the degradation efficiency of α-EC, γ-EC, glutamic acid, PyrCys, γ -GluLeu, γ - GluGlu, γ -GluPhe, and γ GluGly into L-cysteine will be compared by One-way ANOVA, followed by T-tests.
Results and Discussion
To know how to organize this section, remember your hypothesis:“Heat denaturation converts yeast γ-EC into L-cysteine”.
Then, go through your data in a logical order to verify this hypothesis.
Here are the new sections we propose for the “Results and Discussion”:
1) Standardization of Metabolite Identification by HPLC demonstrates that you can identify by HPLC the major
metabolites of γ-EC using the ABD-F derived preparations. Replace Figure 2 by HPLC profiles showing single peaks
for all the molecules that are potential sources of L-cysteine in yeast.
2) Production of L-cysteine by Thermal Treatment
These are the heat degradation that you conducted for each purified cysteine-rich molecule proven to beabundant in your yeast strain:
Question 1: Why did you test 3 different pH conditions?
“Figure 1” shows degradation profiles at pH 3, 5 and 7, which is irrelevant because you only conduct the yeast
extract experiments at pH 5.0.
Enago | Disclaimer: This report was compiled by our Peer Review Expert(s) after careful consideration of yourmanuscript considering several parameters. The author(s) should read the report carefully and address thereviewer’s comments in his manuscript before choosing a journal. This report is based on our expert’s assessmentof the manuscript and should not be considered as a guarantee of manuscript acceptance in the journal.

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Question 2: Why did you conduct time-courses for all molecules, but not pyroglutamic?
Suggestion 1: Prepare a new Figure 1 comparing the heat degradation profiles of the sources of L-cysteine in yeast(α-EC, γ-EC, glutamic acid, PyrCys, γ -GluLeu, γ -GluGlu, γ -GluPhe, and γ -GluGly) at a concentration of 1 mM andpH 5.0.
Suggestion 2: Prepare a new Table comparing the concentration of L-cysteine generated from each substrate (αEC, γ-EC, glutamic acid, PyrCys, γ -GluLeu, γ -GluGlu, γ -GluPhe, and γ -GluGly) at a concentration of 100 mM andpH 5.0 after 4h. Since you conducted these experiments at 3 times, conduct statistical analysis to determine which
product generates the most L-cysteine (one-way ANOVA, followed by T-tests).
3) Mechanism of γ-EC Degradation into L-cysteine
Paragraph 1: Here is how we would arrange it to clarify the text for the reviewers:“The current literature supports the following mechanism for the thermal degradation of γ-EC into L-cysteine inyeast extract: pyroglutamylation of the N-terminal glutamic acid resulting in the formation of PyrCys, followed byhydrolysis of the peptide bond in PyrCys to form pyroglutamic acid and L-cysteine. First, studies showed thatpyroglutamic acid N-terminal groups form spontaneously or by enzymatic catalysis, mostly from N-terminal
glutaminyl residue and N-terminal glutamyl residue(REF). ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Therefore, we hypothesized that theacidic conditions (pH 5.0) of the thermal treatment used in
the present study would support this two-step process in the production of L-cysteine from of γ-EC. “This order allows the reader to follow you through the literature.
Under this first paragraph, show the 2 equations that support the two-step process for L-cysteine
production to justify the different moieties shown in Table 1, 2 and 3. Without these equations, it is impossible tofollow the text in pages 10-12:- Investigation on the mechanism of cysteine liberation from γ-EC (2): the relation with pyroglutamylation of Nterminal glutamic acid.
Focus on the goal of this paper: “To test whether γ-EC is a major source of L-cysteine for the food industry.”- The entire idea of another pathway may be interesting for a thesis, but it seems to account for a minor fraction of
the overall production of L-cysteine, which accumulates at 95% of the rate of γ-EC degradation. In table 3, do you
mean that there may be a common first step and 2 second steps in your 2-step process? Be clear on that.
Conclusion
Condense the text presented in pages 13 and 14:“In this study, we have demonstrated that cysteine was efficiently liberated....Takagi, 2006.”
Include the remark:- Thermal treatment of Saccharomyces cerevisiae haploid strain Nα3 yeast extract liberates L-cysteine from γ-EC,
which may constitutes a significant source of the amino acid for the food industry.
Then finish by changing the text:“Our potential method...under progress.”by a text more focused on a safer mechanism of L-cysteine production than the current Pseudomonas-based highyield bioconversion method. This statement shows that you addressed the problem raised in the Introduction(chapter 2).
References
We have checked the journal guidelines in terms of the references and made some adjustments (see separate fileof references for this article). One of the references (reference no. 17) seems to be missing in the text. I haveplaced additional comments in this regard in the document that lists the references. Please check and cite it inappropriate location in the text.

Enago | Disclaimer: This report was compiled by our Peer Review Expert(s) after careful consideration of yourmanuscript considering several parameters. The author(s) should read the report carefully and address thereviewer’s comments in his manuscript before choosing a journal. This report is based on our expert’s assessmentof the manuscript and should not be considered as a guarantee of manuscript acceptance in the journal.

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Figures
The figures lack legends. Please provide them is a separate file. A single figure is cited in the text and the figure isplaced at respective location in the text. However, figures should be prepared in .pdf format and uploaded during
the submission process.
Tables
No tables are present in this manuscript.
FormatPapers should be as concise as possible and, in view of the international character of the journal, English usages
that may present difficulties to readers whose first language is not English should be avoided. The spellings used
can be British or American, but must be consistent within the manuscript. Authors should express their own
findings in the past tense and use the present tense where reference is made to existing knowledge, or where theauthor is stating what is known or concluded. Original papers should follow the pattern of: Introduction, Materials
and Methods, Results or Findings, Discussion. Follow this order when typing manuscripts: Title, Authors,Affiliations, Abstract, Keywords, Main text (Introduction, Materials & Methods, Results, Discussion for an original
paper), Acknowledgments, Appendix, References, Figure Captions and then Tables.
Style
The document is adequately written. I have made a number of changes and suggestions in the document that will
improve the general level of language. As mentioned above, the document is written in a clear and concise
manner.
Authorship
Please ensure that the authorship meets the criteria as described here http://wustl.edu/policies/authorship.html)

Quality of Research
Originality of research [Rating: Excellent, Good, Fair, or Poor]
Fair. The subject matter is intriguing, and the examples and supporting evidence are illustrative and engaging.
Another observation is that the references seem “thin,” and the paper could be strengthened in this regard, too—
more sources and more current sources (some of the journals listed in the References don’t seem to exist any
longer, as I could not find any websites for them online; other sources seem outdated). Also, it’s not entirely clear
what some of these sources actually are. All of this is to say, the level of scholarship could be raised/improved.
Significance to field [Rating: Excellent, Good, Fair, or Poor]
Good. The manuscript sheds significant light to the existing research. However, we strongly suggest you
incorporate the proposed modifications.
Soundness of study design [Rating: Excellent, Good, Fair, or Poor]
Fair. The Methods section is missing. Also the Discussions section is not sufficiently detailed. We suggest you add
the following to this section to make it stronger:“Results show that purified γ-EC was almost completed converted into L-cysteine in 2h by thermal treatment
under acidic conditions (90°C; pH 5.0). Thermal treatment of yeast extract also supported the liberation of Lcysteine from γ-EC. Investigation of the mechanisms supporting this conversion supports primarily a two-stepprocess...”“L-Cysteine, one of the 20 natural amino acids, plays important roles in foodstuffs, with respect to food texture,color and flavor. For example, L-cysteine improves the rheological properties of bread, crackers, and cookies
Enago | Disclaimer: This report was compiled by our Peer Review Expert(s) after careful consideration of yourmanuscript considering several parameters. The author(s) should read the report carefully and address thereviewer’s comments in his manuscript before choosing a journal. This report is based on our expert’s assessmentof the manuscript and should not be considered as a guarantee of manuscript acceptance in the journal.

Page 8 of 10(Narpinder and others 2002; Bollain and Collar 2004) by reducing disulfide bonds in the dough, which relaxes
gluten interactions (Bloksma and others 1990). In fruit juices, L-cysteine prevents browning of the product (Skalski
and Sistrunk 1974; Montogmery 1983) and preserves flavor during storage (Naim and others 1993a, 1993b). As
new applications are continuously emerging for L-cysteine in the food industry (Starkenmann et al. 2008), thedevelopment of efficient production methods is becoming a priority.”
Ethical soundness [Rating: Excellent, Good, Fair, or Poor]
This section is not applicable for this research.
Sufficiency of data analysis [Rating: Excellent, Good, Fair, or Poor]
Good. There is sufficient data presented in the results and discussed afterwards. However, substantive editing isneeded to enhance clarity.
Overall Rating [Rating: Excellent, Good, Fair, or Poor]
Good. Overall, the research quality is good. The study presents an interesting objective and is designed to address
and meet the aims of the research project.

Manuscript Quality
Clarity of presentation [Rating: Excellent, Good, Fair, or Poor]
Poor. The expression of ideas is very weak. This aspect of the paper requires a lot of attention. While there aregrammatical issues such as misspelled words, the clarity of the text is fair. English editing is suggested to make thetext more readable and ensure it is clear what is the main idea and overall impact of the work.
Organization and Structure [Rating: Excellent, Good, Fair, or Poor]
Good. The manuscript has all the key sections but would benefit from English editing to enhance flow andreadability. Please check with the journal guidelines in case the total no. of words and figures/tables is to beprovided in the title page.
Evidence supports [Rating: Excellent, Good, Fair, or Poor]
Good. The author(s) sufficiently explains and interweaves contemporary and previous studies in the discussion.
Ensure it is clear via submitting this text for English editing.
Adequacy of literature review [Rating: Excellent, Good, Fair, or Poor]
Good. It seems the author has done a good job in referencing previous works and discussing previous studies inlight of the currently presented research. Ensure all referencing requirements are met before final submission towhichever chosen journal.
Overall Rating [Rating: Excellent, Good, Fair, or Poor]
Good. The manuscript’s quality is good. Ensure the manuscript is submitted for English editing to address clarity
issues stemming from grammatical errors.

Enago | Disclaimer: This report was compiled by our Peer Review Expert(s) after careful consideration of yourmanuscript considering several parameters. The author(s) should read the report carefully and address thereviewer’s comments in his manuscript before choosing a journal. This report is based on our expert’s assessmentof the manuscript and should not be considered as a guarantee of manuscript acceptance in the journal.

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Suitability to Journal
Journal Scope and manuscript compatibility
This journal publishes high-quality scientific papers on food science and technology. The article will be suitablewith the new abstract and introduction. Overall, the text is compatible with the journal’s scope. With substantive
English editing and ensuring all journal requirements are met, the text has a nice chance of being accepted.
Journal Coverage and manuscript compatibility
The journal is indexed in the following databases:
Abstracts in Anthropology, Abstracts on Hygiene and Communicable Diseases, Aquatic Sciences and Fisheries
Abstracts, BIOBASE, BIOSIS, Elsevier BIOBASE, Cancerlit, Current Contents/SciSearch Database, Current
Contents/Science Citation Index, MEDLINE, Index Veterinarius, Science Citation Index, Biological Abstracts, CABI
Information, Gale Database of Publications & Broadcast Media, Scopus, Global Health, ISI Science Citation Index,
BIOSIS Toxicology, CSA Life Sciences Abstracts
Journal Quality and manuscript compatibility
The journal has an impact factor of 1.748 and takes 19.6 weeks from submission to first decision. It is aninternational and interdisciplinary journal. The current paper in its state needs to be modified for journal
compatibility. For example, the paper should be double spaced. However, the current one is single spaced. Also,
the references need to be limited to 20.

Next Steps
The following are the three most important improvements that the author needs to make.
Rewrite the Abstract and Introduction, as suggested above, to describe the importance of the study and clearlystate the goal and hypothesis.
Reorganize the Results and Discussion section as suggested to transform this “Thesis design” into a ScientificPaper.
Emphasize in the conclusion the usefulness for the Food industry in terms of identifying a safer process togenerate L-cysteine to improve food texture, color and flavor.
The following are the three most important strengths of this paper, which the author should not lose in the process ofrevision.
Recent identification of a new strain of yeast accumulating the precursor of L-cysteine.
That yeast extract is not toxic or infectious like Pseudomonas.
That L-cysteine production from yeast is a simple and efficient mechanism.

Current Manuscript Status and Recommendation
Overall flow of the manuscript, grammatical errors, and writing style should be corrected before publication.
Recommendation: See Advance Editing

Enago | Disclaimer: This report was compiled by our Peer Review Expert(s) after careful consideration of yourmanuscript considering several parameters. The author(s) should read the report carefully and address thereviewer’s comments in his manuscript before choosing a journal. This report is based on our expert’s assessmentof the manuscript and should not be considered as a guarantee of manuscript acceptance in the journal.

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Enago | Disclaimer: This report was compiled by our Peer Review Expert(s) after careful consideration of yourmanuscript considering several parameters. The author(s) should read the report carefully and address thereviewer’s comments in his manuscript before choosing a journal. This report is based on our expert’s assessmentof the manuscript and should not be considered as a guarantee of manuscript acceptance in the journal.