The Effects of Low-Input (Wild and Organic Farming) Conditions on the Nutritional Profile of Ziziphus jujuba Mill. Fruits from the Valencian Mediterranean

Round 1

Reviewer 1 Report

This manuscript focus on the nutritional and functional composition of three different Ziziphus jujuba fruits which are grown in low input conditions. This type of study highlight the nutritional importance of neglected crop species to bring it to the main stream of fruit market, which is highly appreciated. In general, this study is novel and provides new information about Z. jujuba fruits, which encourage other researchers to explore more in the future. In my opinion, abstract, introduction, M&M, results, discussion and conclusion is presented well however minor correction is required before merits the publication.

1. Line 8: in the key words – suggested to replace wild condition and organic farming by ‘low input farming’

2. Line 68 -76: suggested to remove this paragraph, which is not necessary in my opinion.

3. Line 89-91: ‘In this respect, proximal study, and quantification of bioactive substances, furthermore to other biochemical and morphological constituents, have been postponed.” Is suggested to remove from the manuscript.

4. Line 97: ‘High amounts of heat are required for fruiting.’ Suggested to add the information of average temperature, rainfall and relative humidity.

5. Line 105: authors must add the information about the inputs. The type of organic fertilizer, amount and times applied to the fruiting plants.

6. Line 190 and 205: Only reference is not enough. Suggested to add brief protocol of total sugar and total phenolic content in the manuscript.

Author Response

1. Line 8: in the key words – suggested to replace wild condition and organic farming by ‘low input farming’

Done.

Total polyphenols has been included as a new keyword, to meet a minimum of five.

2. Line 68 -76: suggested to remove this paragraph, which is not necessary in my opinion.

Clarification for the reviewer:

The paragraph that is complementary to the graphical abstract, which was attached as additional material, has been maintained. The reviewer could consider it when viewing it next to the graphical abstract.

3. Line 89-91: ‘In this respect, proximal study, and quantification of bioactive substances, furthermore to other biochemical and morphological constituents, have been postponed.” Is suggested to remove from the manuscript.

Changes have been made to this sentence. With the new wording it makes sense.

4. Line 97: ‘High amounts of heat are required for fruiting.’ Suggested to add the information of average temperature, rainfall and relative humidity.

Done (lines 100-104).

5. Line 105: authors must add the information about the inputs. The type of organic fertilizer, amount and times applied to the fruiting plants.

Done (lines 118-126).

6. Line 190 and 205: Only reference is not enough. Suggested to add brief protocol of total sugar and total phenolic content in the manuscript.

Done (lines 213-217 and 230-236).

Reviewer 2 Report

The jujube fruit broadly consumed in China，and currently, in Spain, it is considered a marginal crop and jujube fruits are undervalued with low economic importance. The present study was to evaluate the physicochemical and bioactive compounds of jujube fruits grown under low-input conditions (wild and organic farming) in the Mediterranean basin. It was found that low-input conditions influence the production of glucose (sweet fruits) and bioactive compounds, as well as the concentration of minerals. The present study was well organized, the data were well presented.      The jujube fruit broadly consumed in China，and currently, in Spain, it is considered a marginal crop and jujube fruits are undervalued with low economic importance. The present study was to evaluate the physicochemical and bioactive compounds of jujube fruits grown under low-input conditions (wild and organic farming) in the Mediterranean basin. It was found that low-input conditions influence the production of glucose (sweet fruits) and bioactive compounds, as well as the concentration of minerals. The present study was well organized, the data were well presented.   

Author Response

Reviewer 2 has not requested any modifications.

Reviewer 3 Report

This article explores the nutritional composition and biochemical properties of jujube fruit cultivated under low-input and organic conditions in the Mediterranean climate of Valencia. This well-executed research sheds light on a lesser-known but valuable fruit,Jujuba. The writing style and analyses employed are appropriate and engaging for readers. However, one significant concern is that the study examines the effects of cultivation using three different cultivars, which might lead to attributing observed differences to genetic variations among cultivars rather than cultivation conditions.

Key Concerns in the Article:

1. The abstract is proportionally unbalanced. The importance of the topic (lines 14-18) can be summarized more succinctly, and more numerical results should be included in the abstract.
2. "SDGs" is not explained.
3. Line 90: Please clarify the intended meaning of this sentence: "furthermore to other biochemical and morphological constituents, have been postponed."
4. In the Materials and Methods section, please specify the climatic conditions of the sampling area.
5. Lines 102-112: Clarify whether the three different Jujuba trees are distinct cultivars, varieties, or local genotypes. Similar genotypes are necessary for accurate comparison between conditions due to potential genetic differences.
6. Regarding the timing of fruit harvest, it is also important that all fruits are harvested at a specific phenological stage (harvest time), for example, when they exhibit a 50% color change, rather than on a specific date. Considering Figure 1, it is evident that fruits from the third cultivar are still unripe, whereas those from the first cultivar have reached full maturity.
7. Line 169: Please explain the means of  phrase "The carbohydrate content was calculated by difference."
8. Lines 170-172: Provide details about how fat, carbohydrates, and protein content were measured.
9. Line 178: Specify the types of minerals analyzed.
10. Line 183: Explain the method of preparing the aqueous solution for the extraction, especially for the low-water-content jujube fruit.
11. In the Materials and Methods, section 2.2 "Chemical reagents," can removed and give more details about the extraction process and the type of solution used for measuring Bioactive Components  (methanolic extract, hydroalcoholic extracts, and which form of vitamin C was measured – fresh or powdered fruit).
12. In Table 1, "Diámeter" and "Geométric" should be corrected to "Diameter" and "Geometric."
13. Explain the high coefficient of variation observed in some averages (Line 526).
14. In the Results section, Table 3 raises a question about the mismatch between total sugar (5g) Vs carbohydrate (about 37 g) and total soluble solids (TSS) content (about 30). Is there another soluble carbohydrate compound in the fruit besides sugar?
15. Lines 401-408: Clarify the reasons for lower color variation in wild and third cultivars. Have they not reached full maturity?
16. Line 559-560: The statement "Jujube fruits under low-inputs conditions are an excellent source of vitamin C for the diet" contradicts the results in Figure 3. Line 501-502 states that jujube fruits grown under organic conditions and of small size have the highest concentration of vitamin C and total polyphenols, with a value of 100%

Author Response

1. The abstract is proportionally unbalanced. The importance of the topic (lines 14-18) can be summarized more succinctly, and more numerical results should be included in the abstract.

Done

2. "SDGs" is not explained.

This information was included in the graphical abstract. This graph was attached as additional material, but it will be included in the manuscript so that there are no errors.

3. Line 90: Please clarify the intended meaning of this sentence: "furthermore to other biochemical and morphological constituents, have been postponed."

This is a typographical error, changed to proposed in the manuscript.

4. In the Materials and Methods section, please specify the climatic conditions of the sampling area.

Done

5. Lines 102-112: Clarify whether the three different Jujuba trees are distinct cultivars, varieties, or local genotypes. Similar genotypes are necessary for accurate comparison between conditions due to potential genetic differences.

Clarification for the reviewer:

The text includes the following phrase "...three jujube cultivars (Z. jujuba Mill.) non-typified were selected...". It is possible that it is different genetic material, but its origin is unknown. Some authors (Li et al., 2007; Qi et al., 2022) classify the kinds based on fruit size. Although the influence of the cultivar is important, so are the growing conditions. Therefore, the manuscript includes size as a genetic reference and low-input conditions. The main objective being low inputs for the nutritional assessment of this paper.

 Li, J. W., Fan, L. P., Ding, S. D., & Ding, X. L. (2007). Nutritional composition of five cultivars of Chinese jujube. Food chemistry, 103(2), 454-460.

Qi, Z., Wu, X., Yang, Y., Wu, B., Fu, H. (2022). Discrimination of the red jujube varieties using a portable NIR spectrometer and fuzzy improved linear discriminant analysis. Foods, 11(5), 763.

6. Regarding the timing of fruit harvest, it is also important that all fruits are harvested at a specific phenological stage (harvest time), for example, when they exhibit a 50% color change, rather than on a specific date. Considering Figure 1, it is evident that fruits from the third cultivar are still unripe, whereas those from the first cultivar have reached full maturity.

Clarification for the reviewer:

The distance between the area of organically produced fruits and wild ones barely reaches 500 m (line 125), so the climatic conditions that influence the ripening of the fruits are very similar. Possible differences are due to genetic variation between cultivars. The criteria for harvesting the fruits of this work focused on the same date, where the fruits, although they have green veins, have a firm texture. The criteria for harvesting the fruits of this work focused on the same date, where the fruits, although they have green veins, have a firm texture.

7. Line 169: Please explain the means of phrase "The carbohydrate content was calculated by difference."

Carbohydrate = 100 – % (crude protein + crude fat + crude fiber + moisture + ash).

Included in the manuscript (line 192).

8. Lines 170-172: Provide details about how fat, carbohydrates, and protein content were measured.

Crude protein was obtained by multiplying the nitrogen value (determined by Kjeldhal method) by 6.25 (AOAC 984.13). (Included in the manuscript).

Crude fat was determined by extraction using petroleum ether as solvent (AOAC 983.23). (Included in the manuscript).

Carbohydrates are already explained in the previous point and included in the manuscript.

Details of the crude fiber have also been included.

9. Line 178: Specify the types of minerals analyzed.

Done

10. Line 183: Explain the method of preparing the aqueous solution for the extraction, especially for the low-water-content jujube fruit.

Done

Section 2.2 "Chemical reagents" has been changed to section 2.2 "Preparation of samples", including the methodology of the extracts. And modified section 2.1. “Plant material”.

11. In the Materials and Methods, section 2.2 "Chemical reagents," can removed and give more details about the extraction process and the type of solution used for measuring Bioactive Components (methanolic extract, hydroalcoholic extracts, and which form of vitamin C was measured – fresh or powdered fruit).

Done.

Section 2.2 "Chemical reagents" has been changed to section 2.2 "Preparation of samples", including the methodology of the extracts.

12. In Table 1, "Diámeter" and "Geométric" should be corrected to "Diameter" and "Geometric."

Done

13. Explain the high coefficient of variation observed in some averages (Line 526).

Done (lines 327-328).

14. In the Results section, Table 3 raises a question about the mismatch between total sugar (5g) Vs carbohydrate (about 37 g) and total soluble solids (TSS) content (about 30). Is there another soluble carbohydrate compound in the fruit besides sugar?

Response to reviewer:

Yes, mainly starch.

15. Lines 401-408: Clarify the reasons for lower color variation in wild and third cultivars. Have they not reached full maturity?

Jujube are non-climacteric fruits and can be consumed in a wide range of ripening stages. The variation in the harvest and the possible stages of fruit maturity may be the cause of the differences found.

Included in the manuscript (lines 438-440).

16. Line 559-560: The statement "Jujube fruits under low-inputs conditions are an excellent source of vitamin C for the diet" contradicts the results in Figure 3. Line 501-502 states that jujube fruits grown under organic conditions and of small size have the highest concentration of vitamin C and total polyphenols, with a value of 100%

Response to reviewer:

The statement "Jujube fruits under low-input conditions are an excellent source of vitamin C for the diet" refers to the set of fruits studied under low-input conditions (organic and wild conditions) in the manuscript. This explains that the three types of fruits are positioned at the base of the pyramid, although individually ACP fruits are the ones with the highest concentration, but it is not contradicted.

Reviewer 4 Report

please see attachment 

Comments for author File: Comments.pdf

Author Response

The title has been shortened at the suggestion of the reviewer 4.

Reviewer 4 indicates using the abbreviation Horticulturae, but it does not exist.

The conclusions has been shortened at the suggestion of the reviewer 4.

Round 2

Reviewer 3 Report

it can be accepted