Tomato Waste as a Sustainable Source of Antioxidants and Pectins: Processing, Pretreatment and Extraction Challenges

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review

The manuscript entitled "Tomato Processing Waste as a Sustainable Resource of Antioxidants and Pectins" comprises 47 typed pages with individual chapters contained in the following pages:

1. Introduction; 1 to 3,

2. Green approaches in extraction of bioactive compounds from food industry waste: 4.

3. Impact of TPW processing and extraction conditions on carotenoid yields: 5 -10

4. Impact of TPW processing and extraction conditions on polyphenol yields: 10 - 17,

5. Impact of TPW processing and extraction conditions on pectin yields 17- 30

6. Major obstacles for widespread industrial utilization of TPW as the source of bioac-tive compounds 30 - 34

The remaining 13 pages are a Reference which contains 176 items of literature, the vast majority of which relate to tomato processing.

In total, the manuscript covers 47 pages.

The authors attempted to present the impact of the processing of organic material, in this case, tomato processing waste, on the possibilities and effects of extracting from its valuable components for human health: antioxidants and pectin.

Here, the first comment arises:

1. The title of the manuscript does not reflect the paper's content. It suggests that the manuscript will only deal with the evaluation of antioxidants and pectins in tomato processing waste and not with the methods of extracting them from the waste. I propose to change the title of the manuscript to one that more closely reflects the actual content of the manuscript and the issues described. The current title mainly refers to the part of the manuscript in Chapter One: Introduction and partly in the last chapter, Major obstacles for widespread industrial utilisation of TPW as the source of bioactive compounds. Altogether, this is about nine typed pages out of 34 pages (about 25%)

2. the authors, in the chapter "Introduction", while describing the advantages of the nutrients contained in tomato waste, omitted essential components from a health point of view, such as vitamins, especially vitamins C, A, and K, and elements such as potassium and iron. Although the manuscript is not thematically concerned with these components, mentioning them in the Introduction would have increased its scientific value.

3. The authors have discussed the processing of various biological materials in many ways. However, in the manuscript, they have mainly focused on the extraction process, which can significantly affect the yield and quality of the products obtained. Therefore, I find it valuable to highlight in the paper the effect of the auxiliary processes and extraction solvents used and the physical conditions of the processes carried out on the quality and quantity of the carotenoids, polyphenols, and pectins obtained. The authors, in the text and with the help of tables, tried to present the results of the study in detail, but unfortunately caused the article to become somewhat dull. There is a lack of diagrams and graphs to give a general idea of the effects of the processes analysed in the manuscript. I suggest considering my comment, grouping the results into appropriate sections, presenting the results graphically, and replacing some of the tables included in the paper this way.

4. The reader of a scientific review article also expects a discussion at the end of the article and conclusions summarising it and the entire content of the manuscript. The chapter entitled "Major obstacles for widespread industrial utilisation of TPW as the source of bioac-tive compounds" can be treated as a partial Discussion. However, there is missing the chapter entitled "Conclusions". Please complete this significant shortcoming.

 

5. The manuscript should be shorter for publication as an article in a scientific journal. The authors could have shortened it considerably, considering my comments on the graphical aspect and the possibility of presenting the content more concisely but informatively.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The broader industrial exploitation of Tomato Processing Waste TPW is currently hindered by challenges in scaling up extraction processes from laboratory research to industrial applications. While green extraction methods offer a sustainable solution, optimizing these processes to maximize yields and preserve the quality of the extracted compounds is critical. Techniques such as RSM and emerging modeling approaches are promising, but their application in TPW extraction remains in the early stages but the processing and pretreatment of raw materials can significantly impact the overall yields and characteristics of the targeted compounds, particularly pectin, emphasizing the need for more in-depth research in this area. These  challenges will require a concerted effort to improve the efficiency, scalability, and environmental sustainability of extraction methods. Integrating these processes into a biorefinery model could further enhance the economic and ecological feasibility of TPW valorization. In this context, the application of  LCA will be crucial for assessing environmental impacts and guiding the development of  more sustainable practices. Significant efforts are still required to bridge the gap between research and industrial implementation, thereby enabling the full valorization of TPW in alignment with circular economy principles.

This is valuable review paper. It could be published after minor revision as below.

 

General Remarks

 

-          Abstract  

Please do not use an abbreviation in the abstract or provide the full name.

-          Correct please page numbers

 

Detailed remarks

 

1.        Page 2 - …”Green extraction techniques such as UAE and MAE”… this should be defined based on proper references.

2.        Page 6 - …”As summarized in Table 1, various green extraction technologies for obtaining carotenoid-rich extracts from TPW have been developed”… These green technologies should be defined and marked in Table 1.

3.        Table – 1,2,3,4 should be self-explaining. Please add additive proper information.

Author Response

Please see the attachment.

Author Response File: Author Response.docx