Comparison of the Nutritional Composition of Quinoa (Chenopodium quinoa Willd.) Inflorescences, Green Leaves, and Grains

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript presents an important contribution to the food science field, studying and comparing the potential nutritional value of parts of quinoa plants (green leaves, grains, and inflorescences). The authors made interesting progress in the analysis of quinoa inflorescences. However, they must adjust many points in the document. The authors did a great job with the proximate analysis of different parts of the plant. However, they used three different varieties, with no comments about them. Table S1 shows varietal differences and interactions in the variety x part of the plant. There are also small details that the authors must correct. I hope the following comments will help the authors to improve their manuscript:

**Title: It is not bad, but I suggest a more direct writing, for example, “Comparison of the nutritional composition of quinoa (Chenopodium quinoa Willd.) inflorescences, green leaves, and grains.”

**Abstract: OK

**Keywords: The authors used keywords too broad. It will harm the visibility of the document by the use of terms like “nutrients,” “leaves,” and “grains.” I suggest using terms like “essential amino acids,” “proximate analysis,” “neglected and underutilized crop,” and “nutritional value.”

1. Introduction

-The current flow is:

Nutritional importance of quinoa > More nutritional importance of quinoa and the lack of studies on the nutritional value of the quinoa inflorescence and infructescence > Nutritional importance of the quinoa infructescence > Flowers and inflorescence of different species as important sources of primary and secondary metabolites > Lack of knowledge of the nutritional value of quinoa inflorescence

The flow is not good. The authors must rewrite the introductions, writing one idea in one paragraph. I would suggest the following flow as an example:

Economic value of quinoa (harvested area and yield, for example) > Nutritional value of quinoa grains > Nutritional value of other parts of the plant (sprouts, green leaves, infructescences) > Lack of knowledge on quinoa inflorescence nutritional value and the objectives of this work

2. Materials and methods

2.1. Study Location, Plant Material, Experimental Design, Field Preparation, and Seed Sowing

-Please explain the used NPK (regular one, slow-released; NPK 10-10-10, 04-14-08, 20-10-10, for example).

-Please explain how much water the plants got per hour with the drip irrigation.

-What was the concentration of the sprayed Sevin, and how many times was it used on the plants?

-There is no need to explain when the grains were harvested in this section because, in the next section, the authors will explain when they collected the inflorescences, leaves, and grains. Please remove the last two sentences of the document or transfer the information to the next section.

2.2. Sample Collection and Preparation

-The authors collected 500 g of leaves and 50 g of grains but did not explain the weight of the collected inflorescences. Please inform the mass or range of mass of collected inflorescences.

2.3. Chemical Analysis: OK

2.4. Statistical Analy: OK

3. Results and Discussion: OK

3.1. Proximate Analysis

-The authors must not only discuss the results among inflorescences, grains, and leavers, but also for the varieties. Quinoa has a richer genetic diversity than major crops (https://doi.org/10.3389/fsufs.2022.960159), so varietal differences are likely to occur. If the authors discuss this in the document, they will fortify their manuscript and may increase the likelihood of citations.

-The authors present the results on a dry basis. However, there is a statistical difference in the moisture on the leaves. Did the authors check if there are statistical differences on a wet basis? I advise adding the wet basis statistical analysis on the supplementary material. If there are differences in the analyses, please discuss them. If not, comment that the other analysis is in the supplementary materials.

-Line 215: The lysine content is 1.1 g, but in Table 2, it is 1.31 g. Please correct the wrong information.

-Line 216: The authors claim that “Generally, green leaves are deficient in methionine…” but the authors do not present results of the methionine content in leaves of other crops. Please present the missing data and discuss the results.

-The results of this work are in the range of the works of Pathan et al. (2019) and Nowak et al. (2015) for the data in Table 1 and Table 2 for the EAA in the leaves. However, the values of EAA for grains are much smaller than reported by Nowak et al. (2015) in Table 2, which may be up to ten times greater than the highest values of this study. Please recheck the values from Nowak et al. (2015) to check if they made any conversion or presented data related to grams of protein, not grams of the part, or something else. The authors must double-check this difference.

3.2. Mineral

-Line 244: What is the mineral with 9623 mg, and is this value related to which part of the plant? The value is not present in the table 3.

3.3. Principal Component Analysis (PCA)

-Please explain in more detail how the PCA contributes to better visualize the data. The PCA repeats the information from tables 1, 2, and 3.

3.4. Correlation of Traits

-The correlations are interesting, but the authors could discuss more about them. For example, may the proteins rich in proline also be rich in K, P, and Mg? May the fibers be rich in pectins, as an explanation for the r=0.77? The authors must give their biochemical insights, which will guide the next steps of the research and, maybe, further publications.

-Did the authors perform the correlation with all the values of all the varieties and all treatments? I advise performing the correlation analysis for different parts of the plants, grouping the varieties, and then for different varieties, grouping the plant parts. If the authors observe the same trend, there is no need to add extra information to the document. If the authors detect a negative correlation for a particular case with a positive correlation in the general condition, they should add this information to the supplementary materials.

4. Conclusions

-Lines 330-331: The authors claim that “However, quinoa green leaves contain higher amounts of protein, fat, and all essential amino acids and minerals than quinoa inflorescences.” However, this is not true because the inflorescences have Mg content significantly different from the leaves. Please fix this detail.

-Lines 333-334: The authors wrote “Our preliminary findings indicate that quinoa stems bearing inflorescence exhibit significant potential as forage for livestock feeding.” Nevertheless, there is no data in the whole manuscript about the proximate analysis of the stem. Although this claim is unsupported by the data, the authors may suggest this topic for further research.

-I suggest adding biochemical analysis of secondary metabolites, oligopeptides, and functional carbohydrates from the inflorescences as future research.

Author Response

Please see attached response. Thank you. 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript of Pathan et al. reports the nutritional comparison of quinoa inflorescences with leaves and grain. I think the study is a good addition to the literature, even though the novelty of the study is limited to only quinoa plant. The manuscript has been written and presented very well and the study has generated a lot of data. That being said there are some minor issues that need to be addressed to improve the quality of the publication. Some of the comments or suggestions are given below-

1.     In the proximate analysis of the Result and Discussion section (page 5, line #208-217), the authors may think about incorporating the amino acid composition of inflorescence of other plants, if available, to compare with amino acid composition of quinoa inflorescence.

2.     In page#6, the line#244 is missing the mineral name “Mg” and also there is a typo in the amount of mineral content (please see  the attached manuscript)

3.     In M&M section, the subheading 2.1 can be divided into two subheadings as “2.1 Study location and Plant Materials and 2.2 Field Preparation, seed sowing and experimental design” to improve the flow of reading.

4.     Please also look carefully at the attached manuscript to see the reviewer’s specific suggestions and other corrections/typos that were not mentioned here.

Comments for author File: Comments.pdf

Author Response

Please see attached response. Thank you. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors greatly improved the text. A few details must be fixed. I hope my comments are helpful:

**Title: OK

**Abstract: OK

**Keywords: OK

1. Introduction

The current flow is:

History and trading of quinoa > Nutritional values of quinoa grains > Nutritional importance of other parts of the quinoa plant > Objective of this work

The flow is adequate, and there is no need to alter the paragraphs.

-Line 34: Please clarify that the paragraph is about quinoa grains. Therefore, I recommend “Quinoa grains are gluten-free and…”

-Line 44: Please define all abbreviations the first time they appear in the text, even common abbreviations like NASA.

2. Materials and Methods

2.1. Study Location, Plant Material, Experimental Design, Field Preparation, and Seed Sowing

-Please use “L” as the unit for liter, not “l.”

2.2. Sample Collection and Preparation: OK

2.3. Chemical Analysis: OK

2.4. Statistical Analysis:

3. Results and Discussion: OK

3.1. Proximate Analysis: OK

3.2. Mineral: OK

3.3. Principal Component Analysis (PCA)

-Line 262: Please check if the authors meant “proximate” in the sentence.

-Figure 2: In the caption, please clarify that Figure 2a is the PCA for Pro, Ash, Fib, Carb, and Fat while Figure 2b is the PCA for Ca, K, Fe, Mg, P, and Zn.

3.4. Correlation of Traits: OK

4. Conclusions: OK

**Supplementary Materials: OK

**Data Availability Statement

-Line 349: Typo: “Raw”, not “row.”

**Author Contributions:

-Please follow the CRediT roles for the author contributions: https://credit.niso.org/

**Funding: OK

**Institutional Review Board Statement: OK

**Informed Consent Statement: OK

**Acknowledgments: OK

**Conflicts of interest: OK

**References:

-Reference 12: Please use lowercase for nouns in the article title as the authors did in the other references.

-Reference 19: Please use lowercase for nouns in the article title as the authors did in the other references.

-Reference 31: Please use lowercase for nouns in the article title as the authors did in the other references.

-Reference 33: Please use lowercase for nouns in the article title as the authors did in the other references.

-Reference 39: Please use lowercase for nouns in the article title as the authors did in the other references.

**Supplementary material: OK

Author Response

Please see attached file. 

Author Response File: Author Response.pdf