The Effect of Different Fining Treatments on Phenolic and Aroma Composition of Grape Musts and Wines
Round 1
Reviewer 1 Report
line 77 hyperoxygenation ? or hyperoxidation ? choose one term, better
hyperoxygenation
line 78 : as before
line 86: total acidity with one decimal
line 86: what is? oNM ?
line 118: what is ?? oNM
line 132 : correct to titratable "acidity"
line 133: correct all the "acids" to "acid"
Table 1: add all the SD's where missing
alcohol : one decimal
Given the concentration of residual sugars, the wines are not dry. Any reason for incomplete fermentation ? What volume of must was fermented? Temperature? duration ? These details are missing in experimental design. Give more details about the fermentation process
Table 2, 3: add all the SD's where missing
Author Response
Dear Reviewer, thank you for reviewing the article and valuable comments. We have accepted all suggested corrections. We converted °NM to Brix values. We added the missing SD values to the tables. The methodology was improved. The explanation for the incomplete fermentation is added - basically, the grapes contained a high initial concentration of sugar, plus SO2 was added at the beginning.
Reviewer 2 Report
The aim of this study was to assess the ability of reducing the phenolic content of grape must and the resulting wine with selected fining agents, spontaneous oxidation and hyperoxidation of must. The focus of the study is interesting and important for winemakers, technicians, and researchers in oenology.
The abstract should be improved. In the first paragraph say ‟The study evaluates the effect of different fining treatments on the phenolic and aroma composition of grape musts and wines″ but also ‟The oxidative method, hyperoxygenation and fining agents…″ These sentences are not clear, it is not understood which treatments were compared and which effects were evaluated. Then, the authors refer to the results putting too much emphasis on the content of caftaric acid. I think they could mention other phenolic compounds as well.
The introduction correctly describes the different aspects involved in the subject of study.
Some aspects of the experimental design should be better described. How many grapes were used? How many repetitions were made of each treatment?
Some specific aspects should be reviewed. In my opinion, the expression ‟the content of titratable acids″ (lines 128, 132-133) is not correct. Instead, it should say ‟titratable acidity″ or ‟total acidity″. In addition, its contents must be expressed in g L-1 and not in ‟mg L-1″ (lines 128, 131).
In the description of the HPLC analysis, the authors indicate ‟HPLC with ultraviolet-visible spectroscopy″ (lines 180-181). I think it would be more correct to indicate directly HPLC-DAD.
In Results, the authors signaled ‟The oxidative and hyperoxygenation variants were quite effective in reducing phenols in the grape must, but unfortunately the concentration of phenols increased in the final wine in these variants″ (lines 227-230). I don't understand these results. Do the authors have any explanation for this?
In lines 237-238 says ‟Gallic acid is released by the hydrolysis of gallate esters of hydrolysable tannins and condensed tannin″. However, the grape and wine tannins are only hydrolysable tannins. I think this sentence should be revised.
In lines 285-286 says ‟Flavonoids are found mainly in grape seeds and skins evolving to polymeric flavonols, also known as tannins″. This phrase is wrong, the correct sentence must refer to flavanols. In successive paragraphs (lines 288, 295, 298, 301), flavanols continue to be confused with flavonols. In all cases the term FLAVANOLS should be used.
The conclusions are too general and vague. I think they should be better adjusted to the results obtained.
Author Response
Dear Reviewer, thank you for reviewing the article and valuable comments. We have accepted all suggested corrections. The abstract has been rewritten, and caftaric acid is highlighted in it for greater importance in oenology, as it is responsible for the browning of wine. We could not fit all phenolic substances into the abstract due to the length of the text. The methodological part was modified and supplemented. Titratable acids were corrected to titratable acidity. Additionally, thank you for the note, titratable acidity values should really be expressed in g.L-1, only YAN should have been expressed in mg.L-1.
In results, we can assume that the precipitation of the polyphenol by oxygen was not sufficient. A higher increase in polyphenolic substances in wine can be observed in the oxidative variant.
Sentence in lines 237-238 is corrected, thank you.
In lines 285-286 it was really confused, now its corrected, thank you.
Reviewer 3 Report
The authors provided an interesting study about the effects of fining treatments on the phenolics and VOCs compositions of must and wine. The methodology, results and discussion need improvement. Also the manuscript needs extensive English editing. Below are some comments to help improve the manuscript.
Line 9 evaluated not evaluates
Line 11 removal of what? Please state
Line 12 please delete “HPLC ()” since you did not used the abbreviation in subsequent sentence
Line 13-17 A lower concentration of caftaric acid was observed in hyperoxygenated (), oxidated ()……….
and the chitosan-treated musts (caftaric acid 44.40 mg·L-1) …….??????. Please rephrase
Line 17-21 please see above comment
Line 22 should be mentioned at Line 13. Also please mention the classes of volatiles after 24 ….. Also why singled out 1-propanol???? Any reason(s)
Line 30-31 one or more is mentioned twice please delete
Line 41 additives like??? Also reference is needed here
Line 43. Citation is needed
Iine 49 please expand and explain how these interactions occur etc
Line 71 please check and correct
Line 72 the expression of the resulting wine.?????
Line 73. hyperoxygenation???? What oxygen rate is deemed hyper? Please mention and cite appropriate literature
Line 75 to 80 please improve. Also statement about novelty should be in line 74.
Line 83 where the experiment was carried out doesnt add any value to the manuscript. Delete please
Line 83 The material ??? what is that? The grapes you mean??? If yes please rephrase
Line 86 9.13 g·L-1 please correct this throughout the manuscript
Line 87 proper sanitary procedures???? Like? Please state
Line 88 at what pressure etc please improve and add details.
Line 98 why do you need to oxygenate that long (5 hr)??? any reason? A statement is needed in this regard
Line 99 to 104 please improve the enhance clarity
Line l01 …. The products for???? What product are you talking about? The authors aren’t describing the methods section well.
Line 103 The samples of???? What of “Treated must ………….
Line 107 removed or terminated????
Line 111 produced ????
The authors should improve line 82 since it is the important part of the methodology. The current descriptions are poor and difficult to read/follow.
Line 117 to 118 please include cities
Line 195 please improve
Line 204 influenced not affects
Line 208 The presence of what????
Line 215-216 repetition from method
Line 226 …… according to the Folin–Ciocalteu method is in method why mention it again?
Figure 3 and 4 where are the post hoc letters? How do readers know which ones are significant etc??? please include
Table 2 and 3 please consider adding p values
Table 4 should be volatile organic compounds not volatile aroma compounds
Table 4 why are some compounds in mg.L-1 and others in mg.L-1. That reminds me …..how did the authors calculate the concentrations? Did they used calibration curves? If yes they should include in the VOCs section and also at what concentration. How did the manage to get the calibration curves samples to mimic that of the wines especially at higher alcohol content.
Author Response
Dear Reviewer, thank you for reviewing the article and valuable comments. We have accepted all suggested corrections and the methodological part has been improved. VOCs were determined according to our previously published article, where the measurement methodology is described in detail, including calibration curves and recovery factor values (appropriately cited in text).
Round 2
Reviewer 3 Report
The authors have improved the manuscript and i recommend accepting in the present form.
