Insight into the Influence of Grinding on the Extraction Efficiency of Selected Bioactive Compounds from Various Plant Leaves

Round 1

Reviewer 1 Report

This is a well written systematic research paper describing roles of particle size and grinding process on the extraction of bioactive compounds from Manuka and stevia rebaudiana plant material. The results presented in the work are new and relevant to the Applied sciences. The methods applied are suitable. Some comments that should be addressed are listed below.

Please provide better figure resolution for graphical abstract

Please put all Latin names in italic trough manuscript (for example Leptospermum scoparium), numbers without any space between (e.g. 50%). Please check the manuscript carefully, to avoid similar mistakes.

Line 47: Which literature. Please, include references

Methods section:

Were the extractions and measurements performed in repetitions? If they was, please indicate in how many.

Line 158-159 Was the filtrate put directly on GC/MS or evaporated?

Line 128: “Leptospermum scoparium” ITALIC

Line 270 add reference

Line 271 “Agrimonia eupatoria, Salvia sp., and Satureja montana” latin names should be written in italic

Line 374 add reference

Conclusion section:

Conclusion section should be improved with potential advantages and disadvantages of grounding particles to the size of 200um and less.

Author Response

Dear Reviewer,

Please see the attachment.

Many thanks,

Author Response File: Author Response.docx

Reviewer 2 Report

Abstract: It requires re-editing after introducing changes in the section: results and discussion and conclusions. The last sentence should be rewritten on the basis of the fundamental complexity of the study, i.e. the effect of the particle size of the extraction yield. 

1. Introduction 

The chapter is written briefly and I do not make many comments. However, I recommend re-editing the paragraphs on the justification of the work undertaken and the aim of the study.

Page 3 Lines 70-86: It should be indicated what new approach to the topic was used, what were the rationale for selecting such material for research. Why was this plant material selected for reaserch, since different extraction methods, different granulation (paricle size) of the material and other extracted substances were used.

Page 3 Lines 81-86: Did the research only look at Manuka leaves?

Table 1: A valuable compilation of literature data. I propose to consider reordering of the columns: Raw material, Main bioactive compound (s), Particle size/Grinder type, Method of extraction, Solid/liquid, Solvent type, Extraction time, Yield, Ref.

2. Materials and Methods

2.2. Chemicals: I suggest putting it at the beginning of the chapter 2.

Table 3.: Please add the "temperature" in degrees Celsius 

Chapter 2. should be supplemented with regard to methods of statistical analysis of the results.

3. Results and discussion

Page 13 Line 237: Effect of grinding process is fragmentation of product  that is described by particle size distribution or degree of granulation. Please rewritten this sentence. 

Page 13 Lines 242-247: In my opinion this is a method description. 

Figure 6. It is not necessary.

Page 18 Lines 332-334: In my opinion this is a method description. 

The discussion requires reference to the research of other authors who used the same material for research but with a different granulation. I suppose it would indicate the validity of the methods used described in the reviewed manuscript. Moreover, I propose that the values of the discussed parameters be included in the citations of the results of other authors' research.

4. Conclusions

Conclusions - too briefly presented. Please refer to the main purpose of the work. The last sentence  (the major conclusion) should be rewritten. 

Summarizing the above, I suggest changing the title of the manuscript. Please consider this possibility: "Insight into the influence of particle size on the extraction efficiency of selected bioactive compounds from various plant leaves".

Author Response

Dear reviewer,

Please see the attachment.

Many thanks,

Author Response File: Author Response.docx