Review Reports - Bioactive Compounds in the Residue Obtained from Fruits of Some Cultivars of Lonicera caerulea

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Manuscript "Compounds with antioxidant activity in the residue obtained from fruits of some cultivars of Lonicera caerulea" is well written and provides valuable information about phytochemical composition of residue obtained from fruits of some cultivars of L. caerulea. It should be interesting for the readers of this journal.

I have some minor comments:

1. Line 133: correct 350C to 35^oC.

2. You mentioned calibration curves of catechin, epicatechin, rutin, ellagic acid, daidzein, quercetin, caffeic acid, coumaric acid, chlorogenic acid, isoquercetin in section 2.2.7. There is no more information about ellagic acid, daidzein, quercetin, caffeic acid, and coumaric acid content in fruits of L. caerulea in the manuscript. In addition to this, please, add information how the other compounds (neochlorogenic acid and cryptochlorogenic acid) were identified.

3. Section 2.2.8: Why two-way ANOVA was applied? What two independent factors were evaluated?

4. What does abbreviation "RSA" mean (Section 2.2.8)?

5. Please, include information about extractions (methanolic and aqueous extracts) in the section 2. Materials and Methods.

6. I have some doubts that the same method was applied for determining total content of different biologically active compounds (phenolic compounds and tannins) Section 2.2.1 and 2.2.2.

7. Figures 1-4: A) I recommend to add error bars on the graphs.

B) Please, explain the mean of different letters.

8. Lonicera should be in italic. Also, it would be more accurate if you named the species (L. caerulea), not just the genus, and when mentioned in the text for the first time it should be written "Lonicera caerulae L."

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The document is interesting due to use of by-products, however, in the title is mentioned that compounds with antioxidant activity were evaluated, and only bioactive compounds are shown. How the authors could demonstrate that these compounds have antioxidant capacity? Some methods should be evaluated, for example, DPPH, ORAC, FRAP, etc.

The results are poor for the publication in this journal. Some comments on the document are described below.

Abstract

Some units of the bioactive compounds should be mentioned. For example. Phenolic compounds (mg GAE/100 g), etc.

Introduction

The authors did not mention the importance of the residue obtained after juice production from Lonicera cultivars. They do not mention the amount of by-products generated.

Materials

The authors mentioned that dehydrated residue was finely granulated with a grinder. What was the particle size? This is important in the extraction and quantification of bioactive compounds.

They did not mention the reagents used in the experiment.

Methods

The same titles should be used in the document.

2.2.1. Determination of total content of phenolic compounds

2.2.2. To determine the total content of tannins

The authors don not mention the name of equipments used.

In the point 2.2.2 Content of tannins is mentioned an aqueous extract and before in phenolic compounds mentioned that methanolic extract was used. Then, what solvent was use?

Authors should use the international system of units and write chemical formulas correctly (NaHCO3).

Results

The statistical information in tables (1, 2, 3 and 4) is not important. For example, median, range, maximum and minimum.

Line 160. The authors mention “compounds with biological activity (Table 1)”, this is not demonstrated in the document, only compounds present in the by-products and it is not mentioned if these compounds are found in peels, pulp, or seeds).

Table 4 mentions that Pearson correlation was used and this is not mentioned in the methodology.

The quality of figures (1-4) is poor, and there is no standard deviation.

Conclusions

These are similar that to the abstract.

Comments on the Quality of English Language

No comments

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript is a descriptive study of the phenolic and flavonoid compounds, anthocyanins, carotenoids, and vitamin content in the dry powder derived from the residue of select Lonicera cultivars.

Table 1 and 2 provide the values of various compounds in dehydrated Lonicera residue. It is imperative to elucidate whether the mean values presented correspond to the aggregation of data acquired from the three distinct cultivars, constituting nine data points (three from each cultivar). The significance of presenting these mean values is questioned, especially when the cultivars were characterized individually.

Furthermore, discrepancies are noted on page 4, where, for example, the total phenolic compounds of Loni and Cera cultivars are reported as 6664.40 mg/100g and 9619.46 mg/100g, respectively. These values do not align with those depicted in figure 1 for the same cultivars. This situation is observed in all parameters. Additionally, it is recommended that the authors incorporate standard deviation bars in Figures 1 and 2.

In addressing the comparison between fresh Lonicera and dehydrated Lonicera residue, it is advised to use values based on dry basis for fresh Lonicera fruits. The current comparison on a per 100 grams basis is deemed misleading due to the disparate nature of the products—one being a fresh product (fruit) and the other a dry product (residue).

Minor comment:

Page 4, line 167: please, correct the name of the cultivar in the sentence:“1858.88 ('Cera') and 2940.00 mg 100 g^-1 ('Cera')”