Isolation of Yeasts from Some Homemade Fermented Cow-Milk Products of Sikkim and Their Probiotic Characteristics
Round 1
Reviewer 1 Report
The paper isolates yeast from traditional Indian fermented dairy products and conducts research on probiotic properties in order to obtain probiotic yeast, which is innovative, especially through Genetic screening for probiotic traits. The thesis proposal is as follows:
1. The content of the thesis is mainly about yeast isolation and probiotic characteristics research. The current title cannot cover all the research content, so it is recommended to revise the title;
2. In line 111 and line 119 of 2.7, culture at 28°C for 24 hours, why use line 114 and line 122 at line 37°C?
3. In lines 263 and 264, there are missing units for moisture content, viscosity, titratable acidity and microbial viable count
4. In 3.3, the analysis of these probiotic genes is somewhat simple, and it is suggested to add, for example, how many copy numbers must be reached for these probiotic genes to function? Which microorganisms are antibacterial genes mainly effective against? In the Discussion section, it is suggested to also add a literature comparison of probiotic genes
Author Response
Answers to Reviewers’ Comments
Probiotic Yeasts Isolated from Dahi and Chhurpi, Home-made Fermented Cow-milk Products of Sikkim, India (Sonam Lama and Jyoti Prakash Tamang)
Reviewer # 1
Comments and Suggestions for Authors
The paper isolates yeast from traditional Indian fermented dairy products and conducts research on probiotic properties in order to obtain probiotic yeast, which is innovative, especially through Genetic screening for probiotic traits. The thesis proposal is as follows:
The content of the thesis is mainly about yeast isolation and probiotic characteristics research.
The current title cannot cover all the research content, so it is recommended to revise the title;
Answer: As suggested by the Reviewer, we revised the title as: Isolation of Yeasts from Some Home-made Fermented Cow-milk Products of Sikkim and their Probiotic Characteristics in the revised manuscript
- In line 111 and line 119 of 2.7, culture at 28°C for 24 hours, why use line 114 and line 122 at line 37°C?
Answer: So, it was typo error. We corrected it as 28°C in the revised manuscript.
- In lines 263 and 264, there are missing units for moisture content, viscosity, titratable acidity and microbial viable count.
Answer: As suggested by the Reviewer, we inserted units in the revised manuscript.
- In 3.3, the analysis of these probiotic genes is somewhat simple, and it is suggested to add, for example, how many copy numbers must be reached for these probiotic genes to function? Which microorganisms are antibacterial genes mainly effective against? In the Discussion section, it is suggested to also add a literature comparison of probiotic genes
Answer: We could not do the whole genome analysis to know the probiotic genes in yeasts.
Apid gene: Saccharomyces cerevisiae DAO-17 (dahi), Kluyveromyces marxianus DPA-41 (dahi) Saccharomyces cerevisiae CKL-10 (chhurpi)
pela gene: Saccharomyces cerevisiae DAO-17 (dahi), Saccharomyces cerevisiae CKL-10 (chhurpi), Pichia kudriavzevii CNT-3 (chhurpi)
Thanks for suggestion. We tired our best to enrich the Discussion section, but due to limited literature of probiotic properties of yeasts, we could collate only the available literature and our own explanation. We request the Reviewer to consider it.
Author Response File: 
Author Response.docx
Reviewer 2 Report
I am agreeing with publication after minor revisions suggested below.
Comments for author File: 
Comments.pdf
Author Response
Reviewer # 2
The paper shows a preliminary study on the probiotic potential of some yeasts isolated in artisan fermented dairy products of Sikkim. Although probiotic properties have been always attributed to LAB and/or other kind of bacteria and literature studies reported only a positive interaction of yeasts with probiotics, by stimulating their growth and enhancing their survival, probiotic potential of some yeasts was preliminarily demonstrated. I am agreeing with publication after minor revisions suggested below.
Answer:
Introduction Line 36: First time that citation Rai et al. 2016 appears, it must be indicated as Rai et al. 2016a, not 2016b, as you did. Moreover, check the journal’s guidelines on citations. Lines 63-64:
Answer: As suggested by the Reviewer, we corrected in in the revised manuscript.
ACE abbreviation should be specified (Angiotensin-converting enzyme); moreover, please correct the term “antioxidant peptides” in “antioxidant activity” because you were mentioning some biofunctional properties, such as ACE inhibitory and antioxidant activity due to bioactive peptides.
Answer: As suggested by the Reviewer, we corrected in in the revised manuscript
Please, expand the final part of introduction regarding the objectives and the experimental plan of the work.
Answer: As suggested by the Reviewer, we expanded objectives and the experimental plan of the work in the Introduction section of the revised manuscript
Figures 1a and 1b (page 2) can become as a unique figure 1, with a single caption. Each can be marked with a letter (a and b) and specified in caption. If you prefer, you can show a single flow chart (so you will have a single scheme) in which an intermediate final product will be Dahi; from that, a new set of operations can continue, leading to Chuurpi product.
Answer: As suggested by the Reviewer, we made Fig. 1 with a single caption in the revised manuscript
Materials and Methods Numerate the equation for moisture content evaluation.
Answer: As suggested by the Reviewer, we corrected moisture (%) in the revised manuscript
Lines 110-11: Was the first inoculation and incubation at 28°C for 24 h done to revitalize cultures that will be subsequently inoculated in the acidified YM broth or YM containing bile? Please, clarify it.
Answer: The first inoculation and incubation at 28°C for 24 h was done to revitalize cultures that was inoculated in the acidified YM broth for Acid Tolerance Test. For Bile Tolerance Test, it was inoculated with YM broth containing 0.3% oxgall (bile)
Please, numerate the equations used to evaluate % hydrophobicity, auto-aggregation (%), and coaggregation (%).
Answer: As suggested by the Reviewer we corrected accordingly.
Lines 199-200: How did you adjust absorbances from 0.08 to 0.1? Numerate the equation used to evaluate lysozyme tolerance. Did you do no statistical tests to evaluate significant differences?
Answer: Adjusted to 0.1; lysozyme tolerance (%). All experiments were performed in triplicate sets with mean ±SD values.
Results Lines 262-265: Please add measurement units for mean viscosity (Cp), moisture (%), microbial load (cfu/mL), and titratable acidity (%).
Answer: As suggested by the Reviewer, we inserted units in the revised manuscript.
Table 2: In the footnote, lowercase “n” must be specified as number of samples, instead of N.
Answer: We corrected.
Figure 2: Please improve resolution of table and caption. Caption is not completely appropriate for describing the figure: it would be better to write “screening of survival percentages of yeasts isolated from Dahi and Chuurpi intended as a) low acid tolerance (pH = 2), and b) bile tolerance (0.3% w/v)”.
Answer: Thanks for suggestion, we revised accordingly in the revised manuscript.
Table 3: I suggest following the same orientation for the titles of each column, to allow a better consultation and understanding of the table.
Answer: Thanks for suggestion, we revised accordingly in the revised manuscript.
Table 4: Organize the table subdivision more clearly. It is not easy to consult it.
Answer: Thanks for suggestion, we revised accordingly in the revised manuscript.
Discussion In general, this section seems a summary of the results, but a poor discussion of the data shown in the previous paragraph is present. I suggest enriching discussions with more bibliographic references, more comparisons, and considerations about the results obtained.
Answer: Thanks for suggestion. We tired our best to enrich the Discussion section, but due to limited literature of probiotic properties of yeasts, we could collate only the available literature and our own explanation. We request the Reviewer to consider it.
Please, check the English form and correct few grammatical inaccuracies.
Answer: We checked and corrected.
Conclusions should be expanded. The relevance of the work, the achieved goals, and the final considerations that can be done in light of the reported results should be specified in this section.
Answer: As suggested by the Reviewer, we tried to expand the conclusion.
Author Response File: Author Response.docx
