Review Reports - The Valorization of Coffee By-Products and Waste Through the Use of Green Extraction Techniques: A Bibliometric Analysis

Round 1

Reviewer 1 Report (Previous Reviewer 2)

Comments and Suggestions for Authors

The authors have addressed all the issues raised during previous round of review process. I have no further issues.

Author Response

First of all, the authors would like to thank the anonymous reviewer for the comments. The answers of the authors have been indicated by “AU”.

The authors have addressed all the issues raised during previous round of review process. I have no further issues.

AU: The authors are pleased to note that the new version of the manuscript has successfully addressed the reviewer's requirements.

Reviewer 2 Report (Previous Reviewer 3)

Comments and Suggestions for Authors

This significantly revised manuscript is substantially improved. I have no further comments and recommend publication as is.

Author Response

Authors would like to thank the anonymous reviewer comments. The answers of the authors have been indicated by “AU”.

This significantly revised manuscript is substantially improved. I have no further comments and recommend publication as is.

AU: The authors are pleased to note that all the improvements implemented in the new version of the manuscript have met the reviewer's requirements satisfactorily.

Reviewer 3 Report (Previous Reviewer 4)

Comments and Suggestions for Authors

After reviewing and carefully reading the manuscript entitled “Valorization of coffee by-products and waste through the use of green extraction techniques: a bibliometric analysis”, I will try to present my opinion concisely and clearly as possible. The paper is written correctly, and the topic is certainly important, especially from the aspect of applying green chemistry in the circular economy in the coffee industry. I respect the opinion of the author in the "defense" of the written manuscript, but what I consider to be the essential problem is the absence of experimental work in the field of chemistry and interpretation of the obtained results.

Unfortunately, I stand by my first decision - not accepting the manuscript, because this manuscript cannot be categorized as an Original Article (Research).

Author Response

Thanks are extended to the anonymous reviewer for their feedback. The responses of the authors have been denoted by the abbreviation "AU".

Unfortunately, I stand by my first decision - not accepting the manuscript, because this manuscript cannot be categorized as an Original Article (Research).

AU: We would like to express our gratitude to the reviewer for recognizing the effort dedicated to this manuscript and confirming its relevance and rigor. We would like to state that we fully respect the reviewer's opinion and understand that the absence of experimental work may have led to the reviewer doubting its categorization as an Original Article (Research).

As previously outlined to the reviewer, this constitutes a bibliometric analysis, which is accorded the status of an original article by virtue of its clearly delineated methodology. Unfortunately, the reviewer's position that the article should be rejected persists. The authors would like to express their full cooperation in resolving this matter, but unfortunately they are unable to take any further action. The final decision, therefore, rests with the editor.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The work is not focused on the expectations of the title.

It is necessary to deepen the analysis by inserting numerical evaluations of the amount of waste of interest and an economic and environmental ranking of the different extraction technologies, considering the recovery products' economic and use characteristics.

Reviewer 2 Report

Comments and Suggestions for Authors

Manuscript Title - Valorization of coffee by-products and waste through the use of green extraction techniques: a bibliometric analysis

Manuscript ID – applsci-3348223

The above manuscript is claimed to be a bibliometric analysis of valorization of coffee by-products through green extraction techniques. For that, the authors used Web of Science database, using keywords like green extraction OR green solvent OR sustainable extraction AND coffee, considering all fields. The authors used VOSviewer 1.6.20 software to analyze the collected data and did a handsome amount of work and presented these results in the form of four figures and two tables. The presentation of results and their discussion are clear enough to understand and give an overview about this field. However, I have following serious concerns on this study, which should be addressed to improve its quality and content:

1. Why only Web of Science database; instead of using Scopus, Google scholar etc. for collecting information for this bibliometric analysis? This could increase the chance of including much more published datasets from different systems!

2. Table 1: The list of publication authors is not listed at all in the number of citations, why? These two categories of authors are completely different!

3. Line 214: “China has made a significant impact in this field” – How? Your analysis results show that the number of publications covers 4.2% (ranking 6) and the number of citations covers 12.9% (ranking 1) of the global value – Does it show that it makes a great impact in this field? You also mentioned that “China is one of the major consumers of tea, rather than coffee [5]” (Line 216-217). These two statements seem contradictory to each other! Please justify.

4. Table 2: The list of extraction methods, products obtained and solvents used are long lists, while these groups used for the bibliometric analysis are only few. Why?

5. Table 2: Chitosan films is also a solvent?

Reviewer 3 Report

Comments and Suggestions for Authors

I appreciate that this is a bibliometric analysis of valorization of coffee by-products, but the patterns of publication that are included in this study do not provide significant insights. Valorization (increasing the importance) of coffee by-products should include metrics of how the by-products are used, how they are obtained, and what compounds are extracted. The abstract listed these items very clearly.

Upon reading the text, the results reported were year of publication, names of institutions where the research was being done, numbers of citations and publications, gender of cited authors, co-occurrence of keywords and words in publication titles. In the discussion was a table (Table 2) of discussion of products, extraction methods, products obtained, and solvents used. The items in Table 2 should have been the items that were analyzed in the results section as these are the key indicators for valorization.

An analysis of the items in Table 2 should also include measures of the amounts of products obtained from the coffee items, an analysis of the methods, and an analysis of the solvents used. Some generalization about what method/solvent/coffee items give the best yield of caffeic acid (or flavinoids, etc.).

In the conclusion, the first sentence reads that "This study underscores the significant potential of coffee by-products and waste as valuable resources for sustainable applications through the use of green extraction techniques." There is no evidence presented in the results or discussion, numerically, statistically, or even anecdotally, that supports this assertion.

I don't think that DBU, n-hexane, acetone, and diethyl ether are green or sustainable solvents. If they are, evidence needs to be provided that these can be used in a green and sustainable way.

Reviewer 4 Report

Comments and Suggestions for Authors

In the manuscript entitled “Valorization of coffee by-products and waste through the use of green extraction techniques: a bibliometric analysis” the author dealt with the bibliometric analysis of innovative green technologies, such as natural deep eutectic solvents, supercritical fluid extraction, ultrasound-assisted extraction, and microwave-assisted extraction of coffee by-products and waste.

Today, these methods are very important due to the increasing application of green chemistry in the circular economy in the coffee industry.

Despite manuscript is well written, in my opinion has no scientific significance, what is contrary to the title of your renowned journal.

I suggest rejection of the manuscript.