Life-Cycle Assessment of Biofortified Productions: The Case of Selenium Potato

Review

Our changes

In the 2.2 section ("Selenium Potato Life Cycle Assessment"), authors might cite and describe ReCipe midpoint method and the Ecoinvent V 3.6 database. Besides they do not cite any study concerning agricultural products where this method (ReCiPe midpoint) is widely adopted, as they state in the paper.

Recipe midpoint method was chosen. It has a difference in the unit of the indicator for each category. This is because a reference substance has been introduced, so that the characterization factor is a dimensionless number that expresses the strength of an amount of a substance relative to that of the reference substance. For all emission-based impact categories and resource scarcity, this is a kg reference substance to one specific environmental compartment, while for land use it is the area and time integrated for one type of land use [34]. In agricultural product studies it is the most widely used due to the large number of indicators relating to this topic [35-36].

In the Figure 4, I suggest title is changed deleting the terms "evaluation of", since it deals with the system boundary of the potato LCA.

System boundary in the LCA of elenium potatoes

The inventory analysis is not clearly described or, at least, its description is very concise to be fully understood.

Primary data from field surveys carried out with the help of the farmer and secondary data were used for the analysis. The latter refer to fertiliser and fuel production processes. These data were obtained from the Ecoinvent V 3.6 database [38]; in addition, both primary and secondary data were referred to the functional unit. The Ecoinvent database facilitates the application of LCA through the availability of a generic consistent background LCI data system, in fact the lack of these can have a strong impact on the quality of LCA studies [39

The "Results and Discussion" section in my opinion is focused too much on the observed differences in the environmental performances between conventional and selenium potato and do not comment the observed impact levels in absolute terms in a separate way. Therefore they go into details whithout looking at the findings from an adequate distance.

results and discussion have been improved

There is a misprint, since I noticed a sentence which has been written twice, although not completely. Lines from 250 to 252 should be removed till the full stop after the word "control". 

has been corrected

Conclusions drawn in the final section are not supported by results

The most important results were obtained in the categories: Global worming, Stratospheric ozone depletion, Terrestrial acidification, Freshwater ecotoxicity, Marine ecotoxicity, Human carcinogenic toxicity, Human non-carcinogenic toxicity, but in relation to the importance of the impact categories considered also in other cases the cultivation of selenium potato brings its advantage to environmental sustainability. The main benefits from a social, economic and environmental point of view make the cultivation of selenium potatoes more sustainable than the conventional method. Overall, the selenium potato as a bio-fortified product obtained to satisfy the modern health-conscious consumer has shown a significant reduction in input, demonstrating in our case study greater environmental sustainability

There are many shortcuts, symbols and notations without sufficient explanation which makes it harder to understand the results. I suggest to put a table in the material and methods section which collects all the shortcuts used in the text, with proper explanations (for example CO2, CFC11, kBq Co-60, NOx etc.). These shortcuts are self-explanatory for researchers but the topic could be valuable for non-experts in this field as well.

a table with explanations has been included

The percentages differences in the results section take value on a high range, from 0.63% up to some 40%. It would be beneficial to distinguish between large and small effects. For example, a 0.5% effect seems marginal for me. Please highlight the importance of these effects in the text.

the importance of percentages in the text has been indicated

Please indicate the potential problems and disadvantages of the research in a few sentences. The part before the Conclusions seems like a good place for this. My concern here is that some of effect (for example the calculated effect on climate change) could be measured very imprecisely, so results are highly indicative in these cases.

The study presents some disadvantages related to the chosen crop, such as the limited number of farms analysed because only they are present in the area considered and the lack of a certified protocol on the cultivation process of the selenium potato replaced at the moment only by operational indications. In order to exceed these methodological weakness the intention is to implement a new research increasing the number of farms under investigation and adopting the protocol of the Consortium "Patata Italiana di Qualità" which is being developed

Abstract: the figure is unnecessary in the abstract in my opinion and usually placed in the text

the figure is the graphical abstract

Line 27: dot is missing after

has been corrected

Line 29: Please provide the missing symbols for iron and zinc.

iron (Fe), zinc (Zn)

Figure 1: “BOFORTIFICTAION” should be “BIOFORTIFICATION

has been corrected

Line 70-75 and line 98-120: This section belongs rather to the introduction than in the Materials and methods section.

has been corrected

Figure 2: Please provide source for the figure

Source: our picture

Line 157: Source is missing for the Ecoinvent V 3.6 database

The latter refer to fertiliser and fuel production processes. These data were obtained from the Ecoinvent V 3.6 database [38]

Line 250-254: There is some repetition in the text. The sentence in line 252 is basically a rephrasing of the previous sentence

has been corrected

Line 300: You write: “The results confirm that “health” products indirectly always have a lower impact”. Please lighten this statement. This research proved this statement only for the Se potato, not for all products

The results confirm that "health" products, such as the Selenium potato, indirectly have a lower impact

Table 1: this table should contain the difference between Se Potato and Conv. Potato in a comparable manner.

has been corrected

Figure 5: The y-axis contains comma after the numbers, which is unnecessary (“80,” for example). Furthermore, y-axis range should be between 0-100% in my opinion, since no values cross the 100% threshold.

has been corrected