The article is poorly articulated; there is a lack of recent bibliography (e.g., 2011, 2013, 2015 are too old). I suggest using FAO as a reference source for publications on the topic and for sustainable practices. Sometimes there is a lack of sources. Figures/tables need revision since there is no correspondence between content and figures; in addition, the table description should be at the beginning of the table and not at the end. The language is good. I suggest implementing the part on sustainability since it is poorly analysed. In particular, I suggest implementing this section; in particular, tomato cultivation is not always sustainable; for example, in Spain, there is a huge problem of desertification due to their cultivation in greenhouses (Almeria). They are also very often used for analyses on new fertilizers.Also, it is better to specify that “sofrito” in a Greek traditional recipe, since it could be mistaken with the Italian “soffritto,”  which is only made with oil and garlic.Any reference to the technology used for the extractions presented should be inserted.In the Conclusion, the concept of biogas should be better analysed, also in the text.