Refractance Window Drying as an Alternative Method for Brewer’s Spent Grain Preservation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Abstract:

The abstract is incomplete as it lacks details on the drying temperature values and the type of experimental design. Additionally, mathematical models must be included.

 2. Materials and Methods

2.1. Raw Material: Indicate the amount of sample used for drying. 

Why were the samples frozen before drying?

 

Line 116: What was the criterion for determining the times in the CCD  design?  (Table 1)

 

Line 129: Place a bibliographic reference in "it is also imperative for food and biological materials to be dried to water activity levels below 0.600

 

Table 2. Drying kinetic models: 

line 144: Other error parameters must be evaluated for good model fit, such as the sum of the squared error (SSE),  mean square error (RMSE), and Chi-square (x2).

 

3.Results and Discussion 

line 225. There is no evidence of analysis of the results of the drying curves (MR). The effect of temperature on drying time is not indicated. It is not compared to other drying methods.

line 238. Table 4. The kinetic parameters of all the models must be presented with their respective errors, to show if the midilli model was the best. An interpretation must be given to the parameter K due to the effect of temperature.

 

Bibliographic references must be placed to compare the results of quality properties with other dried by other methods.

In the conclusions it is not necessary to place the symbols of the quality properties, since these have been defined previously.

 

I have a question: were the best results for quality properties obtained at humidity levels lower than 10%? Since when evaluating the time it is not evident what the respective humidity is. It is important to conclude in the best quality retentions but in dry samples less than 10% and aw less than 0.6.

 

There is no analysis of variance in the results.

 

 

 

 

 

 

Introduction:

In the introduction it is necessary to indicate whether the beer bagasse has been dried by other methods and what results were obtained.  It is possible that alternative methods may yield improved results.

 

 

 

 

Author Response

Below we reproduce the reviewers’ original comments, followed by our responses (R) in italics. Changes in the text in response to the reviewers have been highlighted, as solicited.

Reviewer #1:

Comments and suggestions for authors:

• Abstract: The abstract is incomplete as it lacks details on the drying temperature values and the type of experimental design. Additionally, mathematical models must be included.

 R: The drying temperature and time values, type of experimental design and kinetic mathematical models have been included in the revised version of the manuscript (new page 1).

 Materials and Methods

• 1. Raw Material: Indicate the amount of sample used for drying. 

 R: For each experiment, approximately 75.0 g of fresh brewer’s spent grain was utilized. This information can be found in the original version of the manuscript (New page 3).

 

• Why were the samples frozen before drying?

 R: The fresh samples were previously frozen and stored in a freezer (-18 ^oC) to prevent spoilage of the BSG caused by its high moisture content. This combined with its rich fiber and protein content, makes the material susceptible a rapid microbial growth.

• Line 116: What was the criterion for determining the times in the CCD  design?  (Table 1)

 R: The drying parameters (time and temperature) were selected based on preliminary experiments conducted with brewer's spent grain using a refractance window apparatus. Temperature values were determined considering the maximum temperature achievable with the equipment using hot water, and the drying times were established to ensure the attainment of low levels of moisture and water activity in the dried material.

 Line 129: Place a bibliographic reference in "it is also imperative for food and biological materials to be dried to water activity levels below 0.600

 R: Bibliographic references were included in the revised manuscript (new page 4).

 

Table 2. Drying kinetic models: 

• line 144: Other error parameters must be evaluated for good model fit, such as the sum of the squared error (SSE),  mean square error (RMSE), and Chi-square (x2).

R: The values of sum of the squared error (SSE), mean square error (RMS) and F-values of drying kinetic models were have been incorporated into the new Table 4 (new page 7).

3.Results and Discussion 

• line 225. There is no evidence of analysis of the results of the drying curves (MR). The effect of temperature on drying time is not indicated. It is not compared to other drying methods.

 R: Additional information regarding the statistical analysis of the results of the drying curves has been included in the text (New Table 4 on the new page 7).

• line 238. Table 4. The kinetic parameters of all the models must be presented with their respective errors, to show if the midilli model was the best. An interpretation must be given to the parameter K due to the effect of temperature.

 R: The kinetic parameters of all the models, along with their respective errors, have been included in the revised version of the manuscript (new Table 4, page 7). The interpretation of the effect of temperature on parameter K is in the text of the new page 7.

• Bibliographic references must be placed to compare the results of quality properties with other dried by other methods.

 R: Bibliographic references have been included in the revised version of the manuscript [new pages 2, 10, 11, and reference list].

• In the conclusions it is not necessary to place the symbols of the quality properties, since these have been defined previously.

 R: The symbols of the quality properties have been removed of the text, as suggested by the reviewer (new pages 12 and 13)

 

• I have a question: were the best results for quality properties obtained at humidity levels lower than 10%? Since when evaluating the time it is not evident what the respective humidity is. It is important to conclude in the best quality retentions but in dry samples less than 10% and aw less than 0.6.

R: The experimental design was defined with the objective of analyzing the effects of different conditions of temperatures and processing times on the bioactive compounds of the BSG after the refractance window drying process. Thus, we expected to obtain conditions where overexposure or incomplete drying processes might occur. However, for all bioactive compounds evaluated, the best quality retentions occurred in experiments with adequate moisture levels (lower than 10%) and water activity (lower than 0.600), as detailed in Table 5.

 There is no analysis of variance in the results.

R: Analysis of variance for the drying kinetics and bioactive compounds content have been included in the revised version of the manuscript. The previous Table 4 has been changed and a new Table 6 has been included in the revised manuscript (New pages 7 and 12, respectively)

 

• Introduction: In the introduction it is necessary to indicate whether the beer bagasse has been dried by other methods and what results were obtained.  It is possible that alternative methods may yield improved results.

 R: Information about other drying methods to process the brewer’s spent grain were included in the text (New page 2).

We would like to thank the reviewer for the time spent on reviewing our manuscript helping us improving the article.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

1.       Abstract: quantitative information should be included to understand the main conclusion of research. For example, is RW better than freeze dry?

2.       Line 81: more information regarding brewer manufacturing should be provided, at least the key aspects.

3.       Materials and Methods: Is not there a control to compare outcomes of RW? It is an important gap in the research. Even there would have been to have two “controls”, e.g. “freeze dry” as the “best one” and “hot air” as the “worst one”.

4.       Line 184: organoleptic characteristics should be measured using sensorial evaluation tests. A subjective appreciation of the researcher is not recommended.

5.       Line 201: “preliminary test” or “preliminary results” are inadequate concepts. All experiments must have a concrete objective, and therefore to use the word “preliminary” is ambiguous and incorrect.

6.       Figure 3: image (a) has another magnification. Its barre is of 20 um, while (b), (c), and (d) 10 um. This difficult the comparison.

7.       Results showed in figures 5, 6, 7 and 8 can be shown all together in a table. I suggest change in this way.

8.       Regarding response surface results, a multi optimization analysis is mandatory. There is necessary to know the “unique” process conditions that satisfactorily maximize all response variables.

9.       After optimization analysis, it is common to prepare a “real sample” under these conditions to check results. It was not done.

In general, the idea of research is interesting and useful, but the study appears be “incomplete”.

Author Response

Below we reproduce the reviewers’ original comments, followed by our responses (R) in italics. Changes in the text in response to the reviewers have been highlighted, as solicited.

Reviewer #2:

Comments and suggestions for authors:

1. Abstract: quantitative information should be included to understand the main conclusion of research. For example, is RW better than freeze dry?

 R: Quantitative information has been incorporated in the revised Abstract of the manuscript (new page 1). A sentence highlighting the advantages of refractance window (RW) drying over freeze-drying has been incorporated into the revised text.

 

2. Line 81: more information regarding brewer manufacturing should be provided, at least the key aspects.

R: Additional information about the brewer's manufacturing process has been incorporated into the text (new pages 2 and 3).

 

3. Materials and Methods: Is not there a control to compare outcomes of RW? It is an important gap in the research. Even there would have been to have two “controls”, e.g. “freeze dry” as the “best one” and “hot air” as the “worst one”.

 R: This research exclusively assesses the behavior of brewer's spent grain (BSG) during the drying process using the refractance window methodology. We acknowledge the reviewer's suggestion to compare these results with other drying methods, and we plan to address this aspect in future studies. Thank you for your valuable input.

 

4. Line 184: organoleptic characteristics should be measured using sensorial evaluation tests. A subjective appreciation of the researcher is not recommended.

 

R Sensorial tests were not conducted in this research; however, the suggestion to incorporate such tests will be considered in future studies.

 

5. Line 201: “preliminary test” or “preliminary results” are inadequate concepts. All experiments must have a concrete objective, and therefore to use the word “preliminary” is ambiguous and incorrect.

 

R: The term "preliminary tests" has been replaced with "initial tests" in the revised version of the manuscript (new page 6).

 

6. Figure 3: image (a) has another magnification. Its barre is of 20 um, while (b), (c), and (d) 10 um. This difficult the comparison.

 

R: We acknowledge the reviewer's observation. There was an error in the scale bar of Figure 3(a). The figure has been corrected (new page 7).

 

7. Results showed in figures 5, 6, 7 and 8 can be shown all together in a table. I suggest change in this way.

 

R: The authors have chosen to retain Figures 5, 6, 7, and 8 in the revised version of the manuscript, as they are visually more appropriate for representing the results. However, Figure 9 has been removed and a new table added (Table 6)to facilitate the discussion of the results and their statistical analysis (new page 12).

 

8. Regarding response surface results, a multi optimization analysis is mandatory. There is necessary to know the “unique” process conditions that satisfactorily maximize all response variables.

 R: An optimization study is interesting, however considering the multiplicity of responses and their respective behaviors, as well as the potential diverse applications aimed at maximizing specific bioactive compounds, we have opted to identify the best conditions for each one.

 

9. After optimization analysis, it is common to prepare a “real sample” under these conditions to check results. It was not done.

 R: We agree with the reviewer, that multi-response optimization is also an interesting analysis.

 In general, the idea of research is interesting and useful, but the study appears be “incomplete”.

R: The aim of this study was to evaluate the use of an alternative drying method, specifically refractance window, for processing brewer’s spent grain (BSG). There are no existing studies in the literature that have assessed this technique with BSG. Therefore, we believe that this work can be extended in the future, considering the promising results obtained with RW, as presented in the text.

We would like to thank the reviewer for the time spent on reviewing our manuscript helping us improving the article.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Comments for author File: Comments.pdf

Author Response

Below we reproduce the reviewers’ original comments, followed by our responses (R) in italics. Changes in the text in response to the reviewers have been highlighted, as solicited.

Reviewer #3:

Comments and suggestions for authors:

1. A research paper presenting the possibility of using refractance window drying to dry waste from the brewing industry. The research was planned and carried out properly, only its interpretation needs to be supplemented in some places. In my opinion, the publication should be accepted with minor editorial corrections.

R: We appreciate the reviewer for providing positive feedback and recommend minor editorial corrections for acceptance. 

 

General comments

2. The introduction lacks a sentence on the BSG drying techniques that have been studied so far.

R: New information about BSG drying techniques have been incorporated into the revised version of the manuscript  (new page 2).

 

3. SEM images of the material studied should be better discussed. Why did the temperature change alter the BSG structure?

R: New information about the SEM images (Figure 3) have been included in the text (new page 6).

 

4. In the Conclusion paragraph, there should be no references to the literature and only a synthetic summary of the results obtained. In addition, the summary lacks a clear indication of the advantages of the studied drying method over other available techniques.

R The references have been removed from the Conclusion section, as suggested by the reviewer. Additionally, information about the advantages of the refractance window method over other available techniques has been added in the revised version of the conclusion section (new pages 12 and 13).

 

5. Line 44: Numbers in B vitamins should be in subscript.

R: The numbers in B vitamins have been corrected as suggested by the reviewer (new page 2).

 

6. Line 114 -115: Please explain on what basis exactly such drying parameters (time and temperature) were chosen. Was it preliminary research or literature data?

R: The drying parameters (time and temperature) were chosen based on preliminary experiments conducted with brewer's spent grain in a refractance window apparatus. The temperature values were evaluated based on the conditions of hot water achievable in the equipment, and the drying time periods were determined to be sufficient to reach low levels of moisture and water activity in the material.

 

7. Table 3: The humidity unit is in the header of the table so there is no point in adding it to each row.

R: The moisture units in Table 3 have been corrected as suggested (new page 6).

 

8. Figure 4: The quality of figure 4 should be improved.

R: The Figure 4 has been replaced by a new figure with improved quality (new Figure 4, new page 8) as suggested by the reviewer.

 

9. Line 259: Unnecessary parenthesis.

R: The parenthesis has been removed (new page 9).

 

10. Line 389: Please move equation number 6 higher so that it does not end the paragraph.

R: The number of equation 6 has been moved to the end of the paragraph (new page 13).

The authors are grateful for the reviewer's observations and suggestions.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors corrected the manuscript, but I have a comment and a question.

Comment:

I consider for future work that if the material is going to dry, it is not necessary to freeze it. On the one hand additional costs and on the other hand, loss of quality.

 

Question: table 4, line 404 has errors:

 

On the one hand, the parameters to evaluate the best model are analysis of variance, they are statistical tests. The analysis of variance (ANOVA) is another analysis that determines whether there are statistically significant differences between the means of various groups in an experiment.

 

On the other hand, the F-value parameter is a measure that helps determine if there are statistically significant differences between the means of various groups in an experiment, that is, it is part of the ANOVA. In this case, this parameter does not apply to the models.

 

I recommend reviewing

 

Finally, I am struck by the very high values of the SSE and RMSE statistical parameters; they are normally close to zero for R2 values greater than 0.98. I recommend reviewing

Author Response

REPLY TO THE REVIEWERS COMMENTS (Round 2 – Minor Revisions)

 “Refractance window drying as alternative method for brewer’s spent grain preservation” (applbiosci-2763376)

Below we reproduce the reviewers’ original comments, followed by our responses (R) in italics. Changes in the text in response to the reviewers have been highlighted (in blue).

 

Reviewer #1:

Comments and suggestions for authors:

The authors corrected the manuscript, but I have a comment and a question.

1. I consider for future work that if the material is going to dry, it is not necessary to freeze it. On the one hand additional costs and on the other hand, loss of quality.

R: We appreciate the reviewer’s comments. However, the high moisture of the BSG, coupled with its physicochemical composition, renders the material susceptible to rapid microbial growth and spoilage in a few hours at room temperature. If the material was not frozen, all experiments would have to be carried out sequentially and as quickly as possible, what is technically impossible to accomplish.

 

2. Question: table 4, line 404 has errors: On the one hand, the parameters to evaluate the best model are analysis of variance, they are statistical tests. The analysis of variance (ANOVA) is another analysis that determines whether there are statistically significant differences between the means of various groups in an experiment.

R: Tables 4 and 6 have been corrected (new pages 7 and 13). The ANOVA for difference between means is another interesting possibility, however in this work we choose to conduct a multifactorial regression analysis.

 

3. On the other hand, the F-value parameter is a measure that helps determine if there are statistically significant differences between the means of various groups in an experiment, that is, it is part of the ANOVA. In this case, this parameter does not apply to the models. I recommend reviewing

R: In a regression, the F-Value can also be used to quantify the fit quality. We remove the F-Value in Tables 4 and 6 (new pages 7 and 13).

 

4. Finally, I am struck by the very high values of the SSE and RMSE statistical parameters; they are normally close to zero for R2 values greater than 0.98. I recommend reviewing

R: The SSE and RMSE statistical parameters in Tables 4 and 6 have been reviewed and corrected as request by the reviewer (new pages 7 and 13).

 

The authors are grateful for the reviewer's observations and suggestions.

 

 

Related Papers Published in MDPI Journals (Round 2)

Silva, N.C.; Freitas, L.V.D.; Silva, T.C.; Duarte, C.R.; Barrozo, M.A.S. Use of Refractance Window Drying as an Alternative Method for Processing the Microalga Spirulina platensis. Molecules 2023, 28, 720. doi: 10.3390/molecules28020720

Zalpouri, R.; Singh, M.; Kaur, P.; Kaur, A.; Gaikwad, K.K.; Singh, A. Drying Kinetics, Physicochemical and Thermal Analysis of Onion Puree Dried Using a Refractance Window Dryer. Processes 2023, 11, 700. doi: 10.3390/pr11030700

Gutiérrez-Barrutia, M.B.; del Castillo, M.D.; Arcia, P.; Cozzano, S. Feasibility of Extruded Brewer’s Spent Grain as a Food Ingredient for a Healthy, Safe, and Sustainable Human Diet. Foods 2022, 11, 1403. doi: 10.3390/foods11101403

Núñez, H.; Jaques, A.; Belmonte, K.; Córdova, A.; Lafuente, G.; Ramírez, C. Effect of CO₂ Laser Microperforation Pretreatment on the Dehydration of Apple Slices during Refractive Window Drying. Foods 2023, 12, 2187. doi: 10.3390/foods12112187

Iadecola, R.; Ciccoritti, R.; Ceccantoni, B.; Bellincontro, A.; Amoriello, T. Optimization of Phenolic Compound Extraction from Brewers’ Spent Grain Using Ultrasound Technologies Coupled with Response Surface Methodology. Sustainability 2022, 14, 3309. doi: 10.3390/su14063309

R: These articles were included in the revised manuscript, as requested (new references 33, 30, 10, 31, and 14, respectively).

 

 

Assistant Editor Corrections:

We noticed that some sections/sentences still had significant overlap with previously published articles, and we would therefore request the rephrasing to decrease the similarity part again.

R: The sections/sentences were rephrasing, as requested by the Assistant Editor.

 

Reviewer 2 Report

Comments and Suggestions for Authors

I feel that my main suggestions were not attend.

Quantitative outcomes supporting conclusions are still absent in the abstract. To say that a condition is “better” than another one is insufficient. We need to know how much!

Response surface methodology (RSM) is used to find the optimal conditions that maximize or minimize to a response (or to reach a specific value). It is done using the contour graph and an algorithm for optimization. Nothing in shown in the paper. To choose the best treatment of the runs is not part of a study of optimization using RSM.

Quantitative comparison with other drying methos is absent.

Finally, subjective conclusions are shown, which is inappropriate. In concrete, there is said “Notably, there were no instances of browning or carbonization regions, which are positive characteristics of the refractance window drying method”. Clearly, this is not a conclusion supported by research’s outcomes.

Author Response

REPLY TO THE REVIEWERS COMMENTS (Round 2 – Minor Revisions)

 “Refractance window drying as alternative method for brewer’s spent grain preservation” (applbiosci-2763376)

Below we reproduce the reviewers’ original comments, followed by our responses (R) in italics. Changes in the text in response to the reviewers have been highlighted (in blue).

 

Reviewer #2:

Comments and suggestions for authors:

1. I feel that my main suggestions were not attend.

 R: The authors thank the reviewer for their contributions and inform that they tried to attend as many of its considerations as possible to improve the manuscript.

 

2. Quantitative outcomes supporting conclusions are still absent in the abstract. To say that a condition is “better” than another one is insufficient. We need to know how much!

 R: Quantitative information has been included in the Abstract, as requested by the reviewer.

 

3. Response surface methodology (RSM) is used to find the optimal conditions that maximize or minimize to a response (or to reach a specific value). It is done using the contour graph and an algorithm for optimization. Nothing in shown in the paper. To choose the best treatment of the runs is not part of a study of optimization using RSM.

 R: The Response Surface methodology (RSM) was used in this study to identify the range of the experimental variables values (temperature and drying time) that produced the dried samples with the highest values of the bioactive compounds studied (or as close as possible those observed in the fresh material), i.e, the best range of the operational conditions that guaranteed a final product with good quality. The contour graphs and comments about them were included in the revised version of the manuscript (new Figure 9, new page 11, and comments in new pages 5, 9, 11, 12 and 13).

 

4. Quantitative comparison with other drying methods is absent.

 R: This research exclusively assesses the behavior of brewer's spent grain (BSG) during the drying process using the refractance window methodology. We acknowledge the reviewer's suggestion to compare these results with other drying methods, and we plan to address this aspect in future studies. Thank you for your valuable input.

 

5. Finally, subjective conclusions are shown, which is inappropriate. In concrete, there is said “Notably, there were no instances of browning or carbonization regions, which are positive characteristics of the refractance window drying method”. Clearly, this is not a conclusion supported by research’s outcomes.

 R: Quantitative information is now available in the Conclusion section (new page 13). The sentence reported above was removed, as request by the reviewer (new page 14).

 

We would like to thank the reviewer for the considerations.

 

Related Papers Published in MDPI Journals (Round 2)

Silva, N.C.; Freitas, L.V.D.; Silva, T.C.; Duarte, C.R.; Barrozo, M.A.S. Use of Refractance Window Drying as an Alternative Method for Processing the Microalga Spirulina platensis. Molecules 2023, 28, 720. doi: 10.3390/molecules28020720

Zalpouri, R.; Singh, M.; Kaur, P.; Kaur, A.; Gaikwad, K.K.; Singh, A. Drying Kinetics, Physicochemical and Thermal Analysis of Onion Puree Dried Using a Refractance Window Dryer. Processes 2023, 11, 700. doi: 10.3390/pr11030700

Gutiérrez-Barrutia, M.B.; del Castillo, M.D.; Arcia, P.; Cozzano, S. Feasibility of Extruded Brewer’s Spent Grain as a Food Ingredient for a Healthy, Safe, and Sustainable Human Diet. Foods 2022, 11, 1403. doi: 10.3390/foods11101403

Núñez, H.; Jaques, A.; Belmonte, K.; Córdova, A.; Lafuente, G.; Ramírez, C. Effect of CO₂ Laser Microperforation Pretreatment on the Dehydration of Apple Slices during Refractive Window Drying. Foods 2023, 12, 2187. doi: 10.3390/foods12112187

Iadecola, R.; Ciccoritti, R.; Ceccantoni, B.; Bellincontro, A.; Amoriello, T. Optimization of Phenolic Compound Extraction from Brewers’ Spent Grain Using Ultrasound Technologies Coupled with Response Surface Methodology. Sustainability 2022, 14, 3309. doi: 10.3390/su14063309

R: These articles were included in the revised manuscript, as requested (new references 33, 30, 10, 31, and 14, respectively).

 

Assistant Editor Corrections:

We noticed that some sections/sentences still had significant overlap with previously published articles, and we would therefore request the rephrasing to decrease the similarity part again.

R: The sections/sentences were rephrasing, as requested by the Assistant Editor.

Reviewer 3 Report

Comments and Suggestions for Authors

Manuscript can be accepted in the prestent form.

Author Response

REPLY TO THE REVIEWERS COMMENTS (Round 2 – Minor Revisions)

 “Refractance window drying as alternative method for brewer’s spent grain preservation” (applbiosci-2763376)

Below we reproduce the reviewers’ original comments, followed by our responses (R) in italics. Changes in the text in response to the reviewers have been highlighted (in blue).

 

Reviewer #3:

Comments and suggestions for authors:

Manuscript can be accepted in the present form.

We would like to thank the reviewer for the time spent on reviewing our manuscript helping us improving the article.

 

 Related Papers Published in MDPI Journals (Round 2)

Silva, N.C.; Freitas, L.V.D.; Silva, T.C.; Duarte, C.R.; Barrozo, M.A.S. Use of Refractance Window Drying as an Alternative Method for Processing the Microalga Spirulina platensis. Molecules 2023, 28, 720. doi: 10.3390/molecules28020720

Zalpouri, R.; Singh, M.; Kaur, P.; Kaur, A.; Gaikwad, K.K.; Singh, A. Drying Kinetics, Physicochemical and Thermal Analysis of Onion Puree Dried Using a Refractance Window Dryer. Processes 2023, 11, 700. doi: 10.3390/pr11030700

Gutiérrez-Barrutia, M.B.; del Castillo, M.D.; Arcia, P.; Cozzano, S. Feasibility of Extruded Brewer’s Spent Grain as a Food Ingredient for a Healthy, Safe, and Sustainable Human Diet. Foods 2022, 11, 1403. doi: 10.3390/foods11101403

Núñez, H.; Jaques, A.; Belmonte, K.; Córdova, A.; Lafuente, G.; Ramírez, C. Effect of CO₂ Laser Microperforation Pretreatment on the Dehydration of Apple Slices during Refractive Window Drying. Foods 2023, 12, 2187. doi: 10.3390/foods12112187

Iadecola, R.; Ciccoritti, R.; Ceccantoni, B.; Bellincontro, A.; Amoriello, T. Optimization of Phenolic Compound Extraction from Brewers’ Spent Grain Using Ultrasound Technologies Coupled with Response Surface Methodology. Sustainability 2022, 14, 3309. doi: 10.3390/su14063309

R: These articles were included in the revised manuscript, as requested (new references 33, 30, 10, 31, and 14, respectively).

 

Assistant Editor Corrections:

We noticed that some sections/sentences still had significant overlap with previously published articles, and we would therefore request the rephrasing to decrease the similarity part again.

R: The sections/sentences were rephrasing, as requested by the Assistant Editor.