Characteristic Aroma Compound in Cinnamon Bark Extract Using Soybean Oil and/or Water

Round 1

Reviewer 1 Report

Dear Authors,

The manuscript (applsi-1503190) submitted for review is interesting and important for understanding the effect of heat treatment on aroma compounds, in this case in cinnamon bark.

Overall the manuscript, although well written, I have some comments on it. The main comments are connected with technical notes.

Authors, Please note and address the following comments:

Introduction

Well-described the background to the study. The authors very good described findings in the previous studies.

 Material and methods

The method of analysis is well described, but no information is available on how many samples were analyzed?

Limitations

I have a question. Are there any limitations in this approach to the analysis of aroma compounds in cinnamon bark? If yes, it is worth writing about it.

Conclusions

What are the practical and theoretical implications of the research?

What are the proposals for research in the future?

References

More than half (24) of the cited references come from the years 2015-2021, 13  from 2000-2014, and 3 of references come from the years before 2000.

Authors Please check the correctness of the references citation in line with the Applied Sciences Journal requirements. The authors didn't write the references correctly. Publications from MDPI provide information on how to properly cite. Authors can also find this information in the authors' guide.

This manuscript presents the novelty of this topic and explains changes in aroma compounds during heat treatment with oil and water. This is important as it helps to understand and explain other heat treatments using cinnamon bark. I am pleased to recommend this manuscript for publication in Applied Sciences Journal.

Reviewer

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript of Zhang et al. presents the changes in the relative amounts of different aroma-active extracted from cinnamon bark during stewing for a certain period in water vs. water/soybean oil, with potential applications in meat processing industry. The approach is interesting and that can raise interest from the potential readers of Applied Sciences.

General remarks:

1. The authors should explain why they choose soybean oil as aroma extracting enhancer and no other type of oil.

2. Since different soybean oils from the commerce can have difference compositions, the reproducibility of the results is questionable, as some components (lipophilic antioxidants from soybean oil) can modify (enhance) the extraction of the aroma-active compounds from cinnamon. How are the authors addressing this issue?

4. Introduction needs some tuning and restructuring, to be more clear what is the purpose of the paper. The authors are discussing about stew meat and meat industry, then about the general uses of cinnamon, then coming back to stewing industry.

5. Furthermore, the aims are not very structured.

6. Are there previous investigations showing the enhancing properties of different oils on the extraction of aroma-active compounds from spices or aromatic herbs (not necessarily related to the meat/stewing)? The authors should made a more thorough literature search and report previous relevant literature researches in this aspect. 

Point-by-point suggestions:

L3: In title, use “soybean”

L19-20: Rephrase “whether or not the cinnamon bark extract contained soybean oil” – the authors used soybean oil as an extraction solvent; the way it is now, one can understand that they soybean oil was an intrinsic component of the cinnamon bark

L21, 24 (and all over the manuscript): “contents” should be used at singular; the use of plural is restricted to book table of content

L12-24: The authors should provide some numerical values in the Abstract. For instance, how big were the increments; what was the percentage range of the major aroma-active compounds; what was the ratio between soybean oil and water ?

L28, L83: name of plant species in Italics

L30: Cinnamaldehyde is the major constituent of cinnamon essential oil, not of the cinnamon bark

L52: sentence makes no sense; rephrase

L58: Why are the authors referencing only research from China?

L83: Who authenticated the Cinnamomum species and made sure it is not other, Cinnamomum zeylanicum, for example?

L85: Was the bark pulverized?

L109: Correct the unit after 230.

L127: What does the replicates mean? Three repeated GC analyses or three repeated extractions?

L134: According to the material and methods section, the authors did not determine the actual concentration, but the relative concentration based on a calibration curve of the internal standard (if indeed a calibration curve was used); the authors should mention this, not only put the previous references. Please rephrase the name of Section 3.1. Same for the following subsections.

L135 (and all over the text): use wording such as “relative content”, relative levels, percentages, ratios.

L174: There are no data for 60 and 90 min stewing time. They are all for 30 min.

L174: Title of the Table1 should be modified, so the relative concentrations should be mentioned.

L174: The reporting of ng/g: The g is g of cinnamon bark, g of extract, g of water??

L304-305: Furthermore, “stewing meat with oil, water, and spices was more common rand representative.” – based on which references are the authors stating these?

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have improved the manuscript, according to recommendations