Phytochemical Profile of Eight Categories of Functional Edible Oils: A Metabolomic Approach Based on Chromatography Coupled with Mass Spectrometry

Round 1

Reviewer 1 Report

Review of the article "Phytochemical profile of eight categories of functional edible oils: a metabolomic approach based on chromatography coupled with mass spectrometry"
In my opinion this is interesting, well written and valuable article.

My points for correction:
1. The quality of Figures 1 and 2 should be improved. 
2. The presented results (obtained using HPLC-DAD-RF-MS and GC-MS) are in good agreement with the Authors previous studies presented in [25]. Authors should also compare their results with the results presented in articles by other authors, and discuss this comparison in the Discussion section. 
3. The Discussion section is very short and should be expanded by discussing the results in more detail. 
4. Regarding the sentence:
   "There were identified the specific recognition groups of the authentic samples, comparative to commercial ones (some of them suspected to be adulterated)"
   In the Conclusions section please additionally explain (i.e. in view of the presented results), what you meant by "some of them suspected to be adulterated".

Author Response

Thank you for your comments. See the answers.

Author Response File: Author Response.pdf

Reviewer 2 Report

I have carefully read this manuscript. It is well organized, written, and conducted. However, there are few issues which have to be answered:

1. Section 2, subsections 2.3; 2.4; 2.5; and 2.6: did you convey validation of these methods? If you did, provide the data. If you did not, why so? You have provided only correlation factors, however this parameters is not enough to assess the quality of the analytical method.
2. please provide the table with the fatty acid profiles in analyzed samples.
3. Please provide the chromatograms of the samples..
4. There is no statistical analysis on the data provided in table 2. Please do Tuckey HSD test.
5. There is also lack of standard deviations in table 3. Please provide the standard deviations and Tuckey HSD test for the data.
6. figures 5 and 6 are not clear enough to see the composition. I suggest to present the chemical profiles in Tables.

Author Response

Thank you, please see attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Journal: Applied Sciences

Manuscript ID: applsci-1572920

Type of manuscript: Article

Title: Phytochemical profile of eight categories of functional edible oils: a metabolomic approach based on chromatography coupled with mass spectrometry

 

Review

The authors of the manuscript emphasize the importance of the authentication of functional edible oils and the need to develop effective techniques for detecting adulteration or possible mislabelling. In the presented study they show a metabolomic approach to identifying the phytochemical profile of eight types of edible oils based on their valuable components, treated as biomarkers of authenticity. For this purpose, the authors used the gas- and liquid chromatography-based techniques coupled with diode array, mass spectrometry, or fluorescence detection. The obtained results were then subjected to commonly used in metabolomics statistical analysis using classification models, e.g. Principal component analysis, Partial least squares discriminant analysis, Hierarchical clusters and Heatmaps. In my opinion, the submitted manuscript presents an interesting approach to the considered problem and constitutes a contribution to the existing knowledge. Despite the fact that the paper is quite fairly written and organized, some points need to be explained or improved. Below, there are some comments and suggestions:

General comments:

The study would be more valuable if the authors used more than one authentic sample for each type of oil being tested. More standards of the same oil would make it possible to check whether the variation between the authentic and test samples of oil of the same origin is significantly greater than the variation between the genuine oil samples alone.

 

In addition, it is advisable to attach to the manuscript the percentage of individual fatty acids, the full profile of volatile substances and the concentration of individual phenolic derivatives for the studied group of oils (in a similar form as for carotenoids and tocopherols).

Detailed comments:

Figures 1, 2, 3, 5: Figures should be of better quality (higher resolution). The inscriptions in the PLSDA scoring plots and heatmaps are too small and magnification causes the plot to blur.

Table 3: Shouldn't there be "aPO4" instead of "PO4" in the first column?

1. 320: “from” is redundant.

l.368: The authors combined carotenoids and tocopherols in a single multivariate analysis. As they are not a homogeneous group and their level may be influenced by various factors, it would be better to conduct a discriminant analysis independently for each of these groups.

Figure 4: It would be better plotted the total phenol concentration on the bar graph. Moreover, the connection between the phenol points of commercial and authentic oils implies the continuity of the measurement and is not appropriate in this case.

1. 575: There is a remnant of a template in mentioned line i.e. “In this section, please provide details regarding where data”.

Author Response

Thank you, please see attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Authors answered all issues and accepted necessary changes. Overall, manuscript quality is significantly improved and it can be accepted in the present form.