Egyptian Citrus Essential Oils Recovered from Lemon, Orange, and Mandarin Peels: Phytochemical and Biological Value

Round 1

Reviewer 1 Report

-       In line 24, please define what GNPS-MN means?

-       In line 27 and 28, define DPPH and NO.

-       Throughout the article, write citrus in italics.

-       In section 2.3; An alkanes standard must be injected to calculate the linear retention indices and then determine the composition of the essential oil I recommend also using: Adams, R.P. Identification of Essential Oil Components by Gas Chromatography/Mass Spectrometry, 4th ed.; for the identification of the chemical composition of the essential oil.

-       I recommend obtain the retention linear indices in order to make a correct chemical identification of the essential oils.

Author Response

Dear Reviewer, please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The reviewed manuscript presents a comprehensive and well-organized study regarding the use of citrus peel waste to obtain essential oils. The scientific approach and detailed phytochemical analysis of the resulting products provide valuable insight into their uses.

The main research objective was to investigate the phytochemical and biological value of Egyptian citrus essential oils recovered from lemon, orange and tangerine peels, and to explore their potential applications.

The topic taken up by the authors is both original and relevant.  It sheds light on the potential uses and benefits of essential oils originated from citrus waste, which contributes to the sustainable use of citrus industry by-products.

The authors use advanced techniques such as mass spectrometry (GC/MS) and molecular cross-linking to analyze the volatile components of essential oils and provide detailed insight into their composition and biological activity, including antioxidant, antimicrobial, antifungal and anti-inflammatory properties, thus providing valuable information on the potential medicinal uses of these essential oils. The emphasis on sustainable consumption and use of citrus peel waste is in line with the Sustainable Development Goals (SDGs) and promotes the concept of a circular economy.

In my opinion, the authors should provide more detailed information on the identification of species purchased from the local market. Is the material used in the study homogeneous species or hybrids or breeding varieties? How many samples were used in this study?

Providing detailed information on the reproducibility of essential oil extraction and analysis methods would increase the credibility of this study. Were the analyses single or multiple?

The conclusions presented by the authors highlight the potential applications of essential oils obtained from citrus fruit waste in food preservation, cosmetics and pharmaceutical preparations.

References are appropriate and relevant to the research topic.

Documentation in the form of tables and figures facilitated the review of the study's results.

An element of novelty in this study is the use of citrus fruit waste to extract essential oils. This study also highlights the value of these essential oils as a natural and sustainable alternative to synthetic compounds.

In my opinion, limitations of this study include sample size and scope. The authors chose only one location from which to obtain material for the study and only three species. A wider range of citrus species or varieties could have provided a more comprehensive understanding of the phytochemical composition and biological activity of essential oils from Egyptian citrus. Environmental and economic considerations are also important. This study may not fully address the environmental and economic implications of large-scale production and use of citrus essential oils. Considerations such as the environmental impact of increased citrus waste disposal and the economic efficiency of commercial production may be the subject of further research.

The manuscript is well structured.  The language is appropriate to the scientific context, effectively conveying the concepts and findings and presenting the research results obtained.

Author Response

Dear Reviewer, Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I see that you have made the suggested changes. I only ask that in Table 1, Kovats indices are not correct (they are only used in isothermal conditions) the correct thing is linear retention indices, please change.

Author Response

Dear reviewer, thank you for the comment. Please see the attachment. 

Author Response File: Author Response.pdf