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Medlar Jam Production (Mespilus germanica) with the Use of Sous Vide Method

Processes 2022, 10(8), 1584; https://doi.org/10.3390/pr10081584

by Bohuslava Tremlova

, Hana Koudelkova Mikulaskova, Daniela Slamova, Simona Dordevic

, Bojan Antonic, Johana Zemancova and Dani Dordevic^*

Reviewer 1: Anonymous

Reviewer 2:

Courage Sedem Dzah

Reviewer 3:

Furkan Türker Sarıcaoğlu

Processes 2022, 10(8), 1584; https://doi.org/10.3390/pr10081584

Submission received: 12 July 2022 / Revised: 6 August 2022 / Accepted: 8 August 2022 / Published: 12 August 2022

(This article belongs to the Section Food Process Engineering)

Round 1

Reviewer 1 Report

The manuscript entitled: Medlar Jam Production (Mespilus germanica) with the Use of 2 Sous-Vide Method has been improved.

My only concern is that graph 1, it should be analyzed better.

On the X axis it is important to establish the explicability of the the model in percentage. This should also be done in the Y axis.

In graph 1, please establish based on what variables the three clusters could be formed, and what would it the information that we can establish in this model. Which means, that if in graph 1 the variables of malic and oxalic acid are included, as well as the other variables such as polyphenol content, , FRAP, DPPH.

I would suggest that you could examine some of the articles published that used PCA component analysis.

Hasan, M. M., Sood, V., Erkinbaev, C., Paliwal, J., Suman, S., & Rodas-Gonzalez, A. (2021). Principal component analysis of lipid and protein oxidation products and their impact on color stability in bison longissimus lumborum and psoas major muscles. Meat Science, 178, 108523.

Wu, Z. X., Li, D. Y., Shen, M., Wang, Z. Y., Wang, Z. W., Liu, Y. X., ... & Zhou, D. Y. (2022). Effect of different sous-vide cooking conditions on textural properties, protein physiochemical properties and microstructure of scallop (Argopecten irradians) adductor muscle. Food Chemistry, 133470.

Sadek, O., Touhtouh, S., & Hajjaji, A. (2022). Development of a protocol for the rapid identification of solid materials using the principal component analysis (ACP) method: Case of phosphate fertilizers. Materials Today: Proceedings.

Author Response

Reviewer 1

The manuscript entitled: Medlar Jam Production (Mespilus germanica) with the Use of 2 Sous-Vide Method has been improved.

My only concern is that graph 1, it should be analyzed better.

On the X axis it is important to establish the explicability of the the model in percentage. This should also be done in the Y axis.

We revised the graph 1 and revised the comment. The principal component analysis was done in SPSS software and it is not possible to make a graph with percentage on x and y axis.

I would suggest that you could examine some of the articles published that used PCA component analysis.

We would like to express our thankfulness to the Reviewer for his time and patience.

With kind regards,

Authors.

Reviewer 2 Report

Thank you for the opportunity to review your manuscript on "Medlar Jam Production (Mespilus germanica) with the Use of 2 Sous-Vide Method". Although I find that the manuscript needs some more attention, I think it is good enough to be considered for publication should the following be taken into consideration.

1. You need to generally go through the manuscript to make some grammatical corrections.

2. The statement on line 76 and 77 should be ......"The experiment consisted 8 treatments based on the addition of pectin to samples; 4 samples contained added citrus pectin (1.5 g, produced by Grešík Valdemar) and the rest 4 were prepared without pectin". This is easier to understand.

3. Line 184- You should consider not using the words" extremely decremental". It is not scientific enough. I suggest " addition of pectin significantly decreased antioxidant property"

4. The following statements should be checked properly for technicality:

Line 184: This are your statements. I have made some corrections and I suggest the following instaed:

"This leads to the conclusion that, for traditional method, addition of the pectin is essential, but for sous-vide, it’s not necessary for improving antioxidant activity, according to the DPPH measurements. On the contrary, antioxidant activity reported according to the FRAP assay gave an opposite observation.

5. Line 188-189: Rephrase the statement as suggested. Add a little more information as I have indicated in the statement below.

"The study conducted by Araya et al. (2009) 188 stated that the sous-vide method is a promising strategy for maintaining a number of parameters such as ...................................................in carrots [20]".

6. Lines 201-202: You mentioned this as the reason for the negative effect of pectin addition to jam:

"Based on data this reaction is not happening in significant amounts, for sous-vide method, probably due the insufficient oxidation."

Insufficient oxidation of what? The statement is vague. Is it of pectin or polyphenols. If for polyphenols, then how is it insufficient? And, in any case, oxidation is not good for preservation of antioxidant activity of biological materials. So, that statement does not help your discussion.

7. Line 273-274:

"In addition it seems that the main driver for changes of gallic acid is not the processing method, but temperature, due the direct correlation of temperature and the acid content."

This statement is not technically sound. Temperature is a condition which is an inextricable part of the processing method. Without temperature, there can be no jam preparation.

Also, why did you narrow down to talk about changes in gallic acid, especially when you did not measure its composition in your samples?

I suggest that you consider the fact that polyphenols in general are degraded easily beyond 60-65 degrees Celsius. Also, back that with studies done on the effects of temperature on polyphenol content and biological activity.

8. Lines 244-256 are not relevant to the subject being discussed. Please remove.

9. There is not enough discussion on why the traditional method has given higher TPC and antioxidant activity.

10. Table 3: If no significant differences were observed, then how did you use your alphabets in the Table? It is confusing because the alphabets show that there are significant differences although the data says otherwise.

11. Table 2: Why is it that treatment at 100 degrees without pectin had lower antioxidant activity, but all other treatments without pectin had higher antioxidant activity? It is an interesting observation and should be explained.

General remarks

The above errors and others need to be avoided. Also, do your best to use technical statements instead of flowery language and being too wordy.

I wish you all the best.

Thank you for the opportunity.

Author Response

Reviewer 2

You need to generally go through the manuscript to make some grammatical corrections.

The manuscript was revised grammatically.

The statement on line 76 and 77 should be ......"The experiment consisted 8 treatments based on the addition of pectin to samples; 4 samples contained added citrus pectin (1.5 g, produced by Grešík Valdemar) and the rest 4 were prepared without pectin". This is easier to understand.

We are thankful for this suggestion, the sentence was included.

Line 184- You should consider not using the words" extremely decremental". It is not scientific enough. I suggest " addition of pectin significantly decreased antioxidant property"

It was revised.

The following statements should be checked properly for technicality:

Line 184: This are your statements. I have made some corrections and I suggest the following instaed:

It was revised.

Line 188-189: Rephrase the statement as suggested. Add a little more information as I have indicated in the statement below.

It was revised.

Lines 201-202: You mentioned this as the reason for the negative effect of pectin addition to jam:

"Based on data this reaction is not happening in significant amounts, for sous-vide method, probably due the insufficient oxidation."

The statement was erased.

Line 273-274:

"In addition it seems that the main driver for changes of gallic acid is not the processing method, but temperature, due the direct correlation of temperature and the acid content."

This statement is not technically sound. Temperature is a condition which is an inextricable part of the processing method. Without temperature, there can be no jam preparation.

Also, why did you narrow down to talk about changes in gallic acid, especially when you did not measure its composition in your samples?

The comment was revised.

Lines 244-256 are not relevant to the subject being discussed. Please remove.

It was erased.

There is not enough discussion on why the traditional method has given higher TPC and antioxidant activity.

We tried to revise this section.

Table 3: If no significant differences were observed, then how did you use your alphabets in the Table? It is confusing because the alphabets show that there are significant differences although the data says otherwise.

It was a typing mistake; we apologize for it. The sentence was revised.

Table 2: Why is it that treatment at 100 degrees without pectin had lower antioxidant activity, but all other treatments without pectin had higher antioxidant activity? It is an interesting observation and should be explained.

We tried to revise this section.

General remarks

The above errors and others need to be avoided. Also, do your best to use technical statements instead of flowery language and being too wordy.

Thank you for Your comments and we tried to apply your suggestion as much as possible.

I wish you all the best.

Thank you for the opportunity.

We are thankful to the Reviewer for good comments and suggestions.

With kind regards,

Authors.

Reviewer 3 Report

Line 233: "authors confirm"

Line 270-274: It is stated in this section that there was no significant differences between samples with or without pectin. However, the Table 3 shows the different uppercases which means there are significant differences between samples. Please check and correct the Table or explanation.

Line 302-303: Please check the sentence.

The Results and Discussion section started with the subsection of Antioxidant activity. But, in this same subsection the orgainc acid content of medlar jam was given. Please create a new subsection for the disccussing of organic acid amount of samples.

In general, the authors gave too many literature for supporting their results. However, it is strongly recommended for a better readability that the manuscript should clarify the own results and make explanations why the results changed. In this paper, the literature information is explaining the results. In this case the readability is poored. I can recommend to authors that the papers in the literature should be used for only supporting your results and discussions. So, they do not need to give extra information about the other papers.

Please make some more explanations about PCA. What kind of significant information can be expressed from this figure?

Author Response

Reviewer 3

Line 233: "authors confirm"

It was a typing mistake; we apologize for it. The sentence was revised.

Line 302-303: Please check the sentence.

It was revised.

It was done.

The whole manuscript was revised and we tried to meet Your suggestions as much as possible.

Please make some more explanations about PCA. What kind of significant information can be expressed from this figure?

The figure was revised and PCA was more clarified.

We are thankful to the Reviewer for good comments and suggestions.

With kind regards,

Authors.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The article, despite providing some hints of originality, is far too simple to be considered for publication, being based on only 8 samples. The statistical analysis is unclear (how many replies did you use? How is it possible that -e.g.- 0.30 ±0.01 and 0.31±0.01 -table 4- are statistically different?) and the results are poorly discussed; for instance, you could provide an interpretation of the fact that overall, according to the PCA, there are not differences among the theses, but you have found statistical differences throughout the single analyses, or why traditional cooking revealed the highest values for antioxidant analyses and total phenols and the lowest for oxalic acid.

Author Response

Reviewer 1

Comments and Suggestions for Authors

The article, despite providing some hints of originality, is far too simple to be considered for publication, being based on only 8 samples.

We explained in the material and methods part that actually we are not speaking about 8 samples, but 8 types of vegetarian sausages included in the research.

The statistical analysis is unclear (how many replies did you use? How is it possible that -e.g.- 0.30 ±0.01 and 0.31±0.01 -table 4- are statistically different?) and the results are poorly discussed; for instance, you could provide an interpretation of the fact that overall, according to the PCA, there are not differences among the theses, but you have found statistical differences throughout the single analyses, or why traditional cooking revealed the highest values for antioxidant analyses and total phenols and the lowest for oxalic acid.

We added the information about the statistical analysis and we checked the statistical analysis conduction. We also tried to improve the discussion part as much as possible. We also conducted PCA analysis again and now results are easier to observe

We would like to express our thankfulness to the reviewer for her/his time.

With kind regards,

Authors.

Reviewer 2 Report

It is an intresting article, I suggest the following considerations.

In line 70, it is important to establish the location of Zlin.

In line 72, it is important to establish the conditions of vacuum.

Figure 1 is not clear. What is the percentage of explicability of the model? I suggest to improve the presentation and information.

I suggest that a greater discussion could be given o why with sous vide there were not high values of all the parameters studied. Explain the effect of heat transfer on the parameters studied, possibly explain if the fruit structure could have any effect. Possibly, you could include a visual aid or diagram of the explanation.

I suggest analyzing the following articles:

Soberanes, J. D., Buendía, H. E., Nájera, A. F., De la Rocha González, A., Vela, N. C., & Serrano, G. R. (2017). Product design of a ready to eat Sous vide marinated pork meat based on consumer acceptability and prebiotic index. Revista Mexicana de Ingeniería Química, 16(2), 491-501.

Kathuria, D., Dhiman, A. K., & Attri, S. (2022). Sous vide, a culinary technique for improving quality of food products: A review. Trends in Food Science & Technology, 119, 57-68.

Domínguez-Fernández, M., Yang, P. Y. T., Ludwig, I. A., Clifford, M. N., Cid, C., & Rodriguez-Mateos, A. (2022). In vivo study of the bioavailability and metabolic profile of (poly) phenols after sous-vide artichoke consumption. Food Chemistry, 367, 130620.

Kosewski, G., Górna, I., Bolesławska, I., Kowalówka, M., Więckowska, B., Główka, A. K., ... & Przysławski, J. (2018). Comparison of antioxidative properties of raw vegetables and thermally processed ones using the conventional and sous-vide methods. Food chemistry, 240, 1092-1096.

Lafarga, T., Viñas, I., Bobo, G., Simó, J., & Aguiló-Aguayo, I. (2018). Effect of steaming and sous vide processing on the total phenolic content, vitamin C and antioxidant potential of the genus Brassica. Innovative Food Science & Emerging Technologies, 47, 412-420.

Author Response

Reviewer 2

Comments and Suggestions for Authors

It is an intresting article, I suggest the following considerations.

Thank the Reviewer for the finding that our work is interesting.

In line 70, it is important to establish the location of Zlin.

We added the information about the location of Zlin.

In line 72, it is important to establish the conditions of vacuum.

The information was added.

Figure 1 is not clear. What is the percentage of explicability of the model? I suggest to improve the presentation and information.

We conducted the analysis again and now the Figure 1 is more clear with more clear findings, since we did not use the rotation.

I suggest analyzing the following articles:

Soberanes, J. D., Buendía, H. E., Nájera, A. F., De la Rocha González, A., Vela, N. C., & Serrano, G. R. (2017). Product design of a ready to eat Sous vide marinated pork meat based on consumer acceptability and prebiotic index. Revista Mexicana de Ingeniería Química, 16(2), 491-501.

Kathuria, D., Dhiman, A. K., & Attri, S. (2022). Sous vide, a culinary technique for improving quality of food products: A review. Trends in Food Science & Technology, 119, 57-68.

Domínguez-Fernández, M., Yang, P. Y. T., Ludwig, I. A., Clifford, M. N., Cid, C., & Rodriguez-Mateos, A. (2022). In vivo study of the bioavailability and metabolic profile of (poly) phenols after sous-vide artichoke consumption. Food Chemistry, 367, 130620.

Lafarga, T., Viñas, I., Bobo, G., Simó, J., & Aguiló-Aguayo, I. (2018). Effect of steaming and sous vide processing on the total phenolic content, vitamin C and antioxidant potential of the genus Brassica. Innovative Food Science & Emerging Technologies, 47, 412-420.

We are thankful to the Reviewer for these references. We included as many of these references as possible them in our manuscript and certainly now the discussion is improved.

We would like to express our thankfulness to the reviewer for her/his time.

With kind regards,

Authors.

Reviewer 3 Report

The article title is “Evaluation of Medlar Jam Production Technology (Mespilus germanica) Using the Sous-Vide Method”, but, the research was barely to evaluate the influence on chemical properties of fruit jams, without microbial characteristic, therefore, the title should be revised, otherwise, the supplement of the microbial studies would be necessary.
Statistical Evaluation would be checked carefully, in table 5, total polyphenol,

sample 5, 0.56±.01^e; sample 6，0.56±0.01f , the numbers was the same, but, statistically significant difference??? The same questions were indicated in other tables.

Line 351: Principal component analysis (PCA) did not supplied the detailed method.
Line 198-207, 228-241, 268-296, A large number of research results accumulated, the authors did not analysis and compared those data.

Author Response

Reviewer 3

Comments and Suggestions for Authors

The article title is “Evaluation of Medlar Jam Production Technology (Mespilus germanica) Using the Sous-Vide Method”, but, the research was barely to evaluate the influence on chemical properties of fruit jams, without microbial characteristic, therefore, the title should be revised, otherwise, the supplement of the microbial studies would be necessary.

The title was revised and shorten.

Statistical Evaluation would be checked carefully, in table 5, total polyphenol,

sample 5, 0.56±.01e; sample 6，0.56±0.01f , the numbers was the same, but, statistically significant difference??? The same questions were indicated in other tables.

The statistical differences are observed due to the 4 numbers behind zero, that is the reason why the statistical significances (p < 0.05) were observed.

Line 351: Principal component analysis (PCA) did not supplied the detailed method.

Principal component was revised and done again without rotations. Now it is possible to better see samples.

Line 198-207, 228-241, 268-296, A large number of research results accumulated, the authors did not analysis and compared those data.

More citations were added and the results and discussion part was revised.

We would like to express our thankfulness to the reviewer for her/his time.

With kind regards,

Authors.

Reviewer 4 Report

Having taken time to go through the scope and aim of this special call, I find your manuscript inappropriate for the readership of this journal within the context of the special issue. The following are the reasons:

1. Your paper does not match any of the following scopes:

-The accumulation of byproducts from plant foodstuff production;

-The identification of byproducts from plant foodstuff production;

-The chemical, physical, and microbiological profile of plant foodstuff byproducts;

-The possibility to use plant foodstuff byproducts in other edible matrices as well as in inedible industrial matrices.

-The ecological issues concerning byproducts gained from plant foodstuff production.

2. Your paper is about processing of jam from Medlar fruit. It says nothing about byproducts. This is the aim of your paper: "The present work focused on assessing antioxidant properties of common medlar (Mespilus germanica L.) jam produced by sous-vide technology". You used the whole fruits to process jam. If you had only used the peels or any other portion which could qualify to be a byproduct, then it may have fallen into scope.

3. The DPPH and TPC assays used are too basic without further characterization. You could have also added some basic nutritional analysis or HPLC identification to know the types of phenols responsible for antioxidant property and their quantities.

4. There is no novelty displayed in the manuscript. Nothing new and no new methods and findings.

On the basis given, I do not recommend further review or consideration of this manuscript. It is completely out of scope.

Author Response

Reviewer 4

Comments and Suggestions for Authors

Your paper does not match any of the following scopes:

-The accumulation of byproducts from plant foodstuff production;

-The identification of byproducts from plant foodstuff production;

-The chemical, physical, and microbiological profile of plant foodstuff byproducts;

-The possibility to use plant foodstuff byproducts in other edible matrices as well as in inedible industrial matrices.

-The ecological issues concerning byproducts gained from plant foodstuff production.

Medlar fruits are usually not used in any kind of production, especially in the Czech Republic, and they represent the waste. In that point of view we submitted our work to this special issue.

Your paper is about processing of jam from Medlar fruit. It says nothing about byproducts. This is the aim of your paper: "The present work focused on assessing antioxidant properties of common medlar (Mespilus germanica L.) jam produced by sous-vide technology". You used the whole fruits to process jam. If you had only used the peels or any other portion which could qualify to be a byproduct, then it may have fallen into scope.

We revised the aim of the study. Medlar fruit serve in the garden very often as a waste material for compost.

The DPPH and TPC assays used are too basic without further characterization. You could have also added some basic nutritional analysis or HPLC identification to know the types of phenols responsible for antioxidant property and their quantities.

We applied methods that we are using in the laboratory. We also tried to conduct polyphenolic profile determination on HPLC with DAD detector, but we did not receive the results due to some reason. Otherwise, this method we are often preforming in our laboratory.

There is no novelty displayed in the manuscript. Nothing new and no new methods and findings.

We would like to stress out that there are not so many articles dealing with the production of fruit jam from medlar fruit, especially not with the use of sous-vide technology.

On the basis given, I do not recommend further review or consideration of this manuscript. It is completely out of scope.

We would like to express our thankfulness to the reviewer for her/his time.

With kind regards,

Authors.

Round 2

Reviewer 1 Report

I have read the revisions made, but I remain of the opinion that the article is too simple and offers conclusions of little scientific relevance. The distinction between 8 samples and "8 types of vegetarian sausages" is pointless, as you used the same raw material (cooked at 4 different temperatures and prepared with 2 different procedures -traditional and sous-vide- with or without pectin); not to mention that you used yourself the term "sample" in the text. At the same time, you analyzed 3 to 5 replies of the same sample, so that you had only a small -overall- statistical sample.

Author Response

I have read the revisions made, but I remain of the opinion that the article is too simple and offers conclusions of little scientific relevance. The distinction between 8 samples and "8 types of vegetarian sausages" is pointless, as you used the same raw material (cooked at 4 different temperatures and prepared with 2 different procedures -traditional and sous-vide- with or without pectin); not to mention that you used yourself the term "sample" in the text. At the same time, you analyzed 3 to 5 replies of the same sample, so that you had only a small -overall- statistical sample.

We would like to stress out one more time that we produced 8 types of medlar fruit jam, where we applied sous-vide technology. To investigate the role of sous-vide technology we applied different temperature regimes. We also produced the jam from this not traditional fruits in the traditional way. We still think that our research would be a good starting point for future investigations.

We would also like to thank to reviewer for the honest opinion and suggestions,

With kind regards,

Authors.

Reviewer 2 Report

All of the issues were addressed, however, there is something that could be improved.

PCA results should be analyzed better, it is important to establish the percentage that could be explain with this model, in particular in each axis, and probably describe in a better way what is this graph trying to establish. Does it include all of the parameters analyzed? if so, why aren't they shown in the graph. Please explain in detail.

Author Response

All of the issues were addressed, however, there is something that could be improved.

The additional information about PCA results were added.

We would also like to thank to reviewer for the honest opinion and suggestions,

With kind regards,

Authors.

Reviewer 3 Report

1. Statistical Evaluation would be checked carefully, in table 5, total polyphenol,

sample 5, 0.56±.01e; sample 6，0.56±0.01f , the numbers was the same, but, statistically significant difference??? The same questions were indicated in other tables.

The statistical differences are observed due to the 4 numbers behind zero, that is the reason why the statistical significances (p < 0.05) were observed.

The data should been shown in the 4 numbers behind zero

2. Line 351: Principal component analysis (PCA) did not supplied the detailed method.

Principal component was revised and done again without rotations. Now it is possible to better see samples.

How to do PCA ?

Author Response

Statistical Evaluation would be checked carefully, in table 5, total polyphenol,

sample 5, 0.56±.01e; sample 6，0.56±0.01f , the numbers was the same, but, statistically significant difference??? The same questions were indicated in other tables.

The statistical differences are observed due to the 4 numbers behind zero, that is the reason why the statistical significances (p < 0.05) were observed. That is the reason for the same number.

Line 351: Principal component analysis (PCA) did not supplied the detailed method.

Principal component was revised and done again without rotations. Now it is possible to better see samples.

We would also like to thank to reviewer for the honest opinion and suggestions,

With kind regards,

Authors.

Reviewer 4 Report

The authors have tried to respond to earlier comments satisfactorily to some extent. But going through the entire work again, there quite a lot of very important issues that need to be dealt with.

Abstract

Line 11-12. The aim of the research was to evaluate the influence of sous-vide technology on chemical properties of fruit jams produced with medlar fruit (Mespilus germanica L.), the fruit that are often displaced and represent the waste in the garden. This part is not needed.

Line 17-19. Among sous-vide processed samples with the highest (p < 0.05) antioxidant activity were processed at 80 °C and they contained pectin; the results were the following: total polyphenol content 0.56 ± 0.01 mg gallic acid/kg; FRAP 0.32 ± 0.01 µmol Trolox/g; DPPH 21.39 ± 0.33 %.

-What is the pectin content about here? No method in the work mentioned pectin content analysis and what is the relevance? In any case, pectin is involved and used in jam production.

-Your units of measurement are not uniform. You have reported TPC in mg/kg but FRAP per g. Why not maintain consistency? Moreover, FRAP values are extremely too low to be realistic.

Line 21-22. The obtained results showed how fruit jam production with the use of sous-vide technology can affect chemical properties of this food commodity. This statement is not entirely true because TPC and antioxidant activity by DPPH and FRAP do not tell you about the how the technology affects chemical properties of the product. Lots of simple chemical evaluations such as titratable acidity, total solids, brix, pH etc have not been determined to properly characterize your jam. These are key parameters used to identify jams.

Line 96- How did you use gallic acid in this assay? It has not been shown.

Line 110- How did you use trolox in this assay? It has not been shown

Line 126-135- The DPPH assay used was not good enough to determine antioxidant activity because DPPH does not dissolve well in ethanol. Moreover, the authors did not even use absolute ethanol which makes the situation worse. The best solvent for DPPH is methanol as it gives the best absorbance. That may explain the extremely low values. There are many very good exmaples of studies that have used the DPPH assay. Why not follow and cite their methods instead?

Line 140-142. Samples for the determination of organic acids were prepared from 10 g of mass and 50 mL of distilled water, after centrifugation, the samples were filtered and then the supernatant was used for the analysis. This statement does not help at all. There are a number of issues here:

a. You cannot add 10g sample to 50 mL water, centrifuge, filter and use supernatant for HPLC without further purification or treatment of supernatant. It needs to go through refinement for HPLC else the column will be choked and can't run. So, this is not clear.

b. You have not described your mobile phases in the work. What solvents did you use?

c. What was your elution method?

Line 146-147. 4 mM sulfuric acid and Agilent ChemStation software (Agilent, Santa Clara, CA, USA, revision: B.04.02) were applied for the mobile phase.

-This statement does not make meaning. You used 4mM sulfuric acid and Chemstation software for mobile phase??? How?

Line 150- The resulting values of the individual analyses (all samples were analyzed 3 to 5 times) were shown in tables as the mean ± standard deviation

- This is not statistically sound. You should chose if you want to have tests done in triplicates or done 5 times. State specifically which you used and stick to it.

Line 157-176. All that you have stated there have nothing to do with your study and should not appear there in results. If anything, they may be in your introduction.

In your results, discuss same concepts together. Do not separate them. For example, if you are discussing antioxidant activity, put all antioxidant activity results together and discuss them and compare all treatments. Do not discuss DPPH separately and FRAP separately as though they were measuring different properties. You could put DPPH and FRAP in one Table. What is the relationship between TPC and antioxidant activity, between temperature and TPC and antioxidant activity, between organic acid contents and TPC and antioxidant activity. Some form of correlational analysis could also help your discussion.

In all, I think the study is not well structured, the scientific approaches are not sound enough technically.

The entire manuscript needs critical English Language proofreading.

This work cannot be published in its current form. It must be reworked on and well-presented.

Thank you for giving me the opportunity to review your work.

All the best

Author Response

The authors have tried to respond to earlier comments satisfactorily to some extent. But going through the entire work again, there quite a lot of very important issues that need to be dealt with.

Abstract

This part was revised.

-What is the pectin content about here? No method in the work mentioned pectin content analysis and what is the relevance? In any case, pectin is involved and used in jam production.

We did not determine pectin content in our work. We were adding pectin to our samples.

-Your units of measurement are not uniform. You have reported TPC in mg/kg but FRAP per g. Why not maintain consistency? Moreover, FRAP values are extremely too low to be realistic.

It is an ordinary praxe to represents different methods in different units.

We agree with the reviewer that additional analysis could have been applied, but in our research we did the mentioned analysis.

Line 96- How did you use gallic acid in this assay? It has not been shown.

Gallic acid we used as the standard for the determination of total polyphenol content.

Line 110- How did you use trolox in this assay?

It was used as the standard for the determination of FRAP antioxidant property.

We agree with the reviewer that different solvents can be used for the extraction, but in our laboratory we mainly used ethanol.

You cannot add 10g sample to 50 mL water, centrifuge, filter and use supernatant for HPLC without further purification or treatment of supernatant. It needs to go through refinement for HPLC else the column will be choked and can't run. So, this is not clear.

It was revised, we used microfilter.

You have not described your mobile phases in the work. What solvents did you use?

The information was added.

What was your elution method?

It is revised and written that we used isocratic elution method.

Line 146-147. 4 mM sulfuric acid and Agilent ChemStation software (Agilent, Santa Clara, CA, USA, revision: B.04.02) were applied for the mobile phase.

-This statement does not make meaning. You used 4mM sulfuric acid and Chemstation software for mobile phase??? How? ?

We apologize for this mistake, it was revised.

Line 150- The resulting values of the individual analyses (all samples were analyzed 3 to 5 times) were shown in tables as the mean ± standard deviation

- This is not statistically sound. You should chose if you want to have tests done in triplicates or done 5 times. State specifically which you used and stick to it.

It was revised.

Line 157-176. All that you have stated there have nothing to do with your study and should not appear there in results. If anything, they may be in your introduction.

It was revised.

We put DPPH and FRAP methods in one Table. It is obvious that the polyphenolic content positively correlates with higher antioxidant activity measured by DPPH and FRAP methods.

In all, I think the study is not well structured, the scientific approaches are not sound enough technically. The entire manuscript needs critical English Language proofreading. This work cannot be published in its current form. It must be reworked on and well-presented.

We are thankful to the reviewer for good comments and suggestions. We tried to revised our manuscript as good as possible.

With kind regards,

Authors.

Round 3

Reviewer 1 Report

I have read the same article three times; some discussions have changed and the description of the methods has been expanded, but the experiment is exactly the same, this is why I cannot change my opinion. The trial is not wrong, it is merely way too simple -in my opinion- to deserve a publication in a high-if journal.

A curiosity, in table 2 how is it possible that 0.44 is not statistically different from 0.31, but 0.32 is statistically different from 0.30?

Reviewer 4 Report

Thanks for the opportunity to review your paper. You have tried to respond to some of the comments, and you still have a lot to do if this manuscript is to be further processed.

The lack of line numbers in the revised manuscript makes it difficult to review. However, the following have been noticed and need to be addressed:

Abstract

1. Total phenol content is not method, it is a test of determination of phenols. So, it must be appropriately defined in the abstract.

2. 2,2-diphenyl-1-picrylhydrazyl (DPPH) is a chemical, not a method and cannot be captured as such. State the method, not just the chemical.

3. This statement “Among sous-vide processed samples with the highest (p < 0.05) antioxidant activity were processed at 80 °C and they contained pectin;” does not seem to be understandable. Please rephrase.

4. total polyphenol content 0.56 ± 0.01 mg gallic acid/kg as reported in the abstract is extremely low for a jam. Please, do you have a control measurement?

Introduction

1. The last statement of your introduction says this “The research was focused on assessing antioxidant properties of common medlar (Mespilus germanica L.) jam produced by sous-vide technology.”. Did the study really only consider the antioxidant property of the jam? I think you need to include the TPC determination.

Materials and methods

1. This statement “In this way was prepared 8 types of experimentally produced Medlar jam samples were and four of them were also added 1.5 g of pectin” does not really come out clear. It is difficult to understand.

2. How did you select the temperatures 60, 70 and 80 degree Celsius? What if the best product was to be made at 83.5 degree Celsius? How would you know?

Results

1. This statement “But for traditional method absence of pectin was extremely decremental to antioxidant activity. Which leads to the conclusion that for traditional method addition of the pectin is essential, but for sous-vide it’s not necessary and should not be added to achieve optimal results.” is not entirely true. You seem to only be making this conclusion based on your DPPH data and not FRAP. FRAP data is saying otherwise because sample 8 had the highest antioxidant property without pectin but had the lowest for DPPH.

2. This statement “Similar findings were also introduced in study by, Araya et al. 2009 confirms that the sous-vide method is a promising strategy for maintaining a number of parameters in carrots [20].” cannot be correct. From all indications in this study, sous-vide method has rather given the lowest antioxidant activity for both FRAP and DPPH assays. So, your conclusions and discussions are not supported by your own data.

General remarks

Having gone through the entire work, it is very simple but the authors have not been able to present it well enough. Also, the authors have not done a good work to discuss their results well with scientific backing and explanation of concepts. Also, conclusions drawn from data are not supported by the data themselves. That is not good for the reputation of Processes and MDPI.

Article Menu

Medlar Jam Production (Mespilus germanica) with the Use of Sous Vide Method

Domínguez-Fernández, M., Yang, P. Y. T., Ludwig, I. A., Clifford, M. N., Cid, C., & Rodriguez-Mateos, A. (2022). In vivo study of the bioavailability and metabolic profile of (poly) phenols after sous-vide artichoke consumption. Food Chemistry, 367, 130620.

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