Optimization of Texture-Modified Yellowfin Sole (Pleuronectes aspera) by Enzymatic Treatment and Superheated Steam Treating to Improve Quality Characteristics
Round 1
Reviewer 1 Report
The paper shows the use of enzymatic treatment as an alternative to thermal treatment when softening the texture of yellowfin fish, aiming at facilitating its consumption by elderly people. In addition to texture and sensory analyses, the amino acid and nutritional composition were determined. Microbiological and physicochemical analyses were performed to evaluate the enzymatic treatment and product shelf life. The paper is clearly written and well organized. However, I have some comments and questions before considering it for publication.
Regarding the Experimental Design:
* Why did authors choose “time” as an independent variable? Why not study enzyme’s ratio (Neutrase:Protamex) or incubation conditions?
* Why did you keep non-significant variables in the model instead of reparametrize it?
* Take care about the number of significant digits. Is it possible to express hardness as [kN/m2]?
* Table 3: Remove “<” symbol of “ <0.013” and “ <0.079” and always use lower case for p-value.
Line 216: do not write R2 values as “Y1 = 0.931, Y2 = 0.913”
Lines 233-235: since protease activity is usually described as “hydrolysis per time”, don’t you think this linear relationship between enzyme concentration and time should be already expected?
Lines 340-342: If you say that “the difference was not significant”, take care when suggesting that lipid peroxidation was inhibited by enzymatic treatment.
Lines 365-367: Hardness units are missing.
Finally, please, remove DCC from the paper and report the selection of condition in another way, such as referring to preliminary studies. Despite showing good correlation and F values, this design is depreciating the paper. In this kind of kinetic study, the use of “time” as an independent variable should be avoided. Other variables could be chosen, and then the responses could be studied over time.
Author Response
Please check the attached file including the responding letter for Reviewer 1.
Best regards
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Submitted manuscript is very well written and pleasant to read. The topic undertaken by the authors is very relevant as problems relating to aging society are becoming more and more important. The introduction is properly written and leads well the reader to the topic. Materials and methods are described accurately enough. The results are clearly presented and the discussion is lead well. I have only few minor remarks (please see detailed comments) that do not influence the overall value of the manuscript. Conclusions are supported by the results, therefore submitted manuscript can be recommended for publication in Processes.
Detailed comments:
Line 400-408 why values for non-enzyme processed sample are not provided? Moreover why it is implied that texture modification resulted in changes to TMA, as it could be also related to steam treatment.
Line 421-422 please rephrase, sentence to colloquial for research article.
Line 454-494 in my opinion the “reference” results and discussion related to that should be deleted. It is pointless and proves almost nothing. I suggest just discussing the nutritional value of texture modified fish similarly to protein composition and just referencing it to sum of acids form cited study.
Line 498-502 repetition of data, please delete.
Line 583-590 similar decrease in hardness after storage for all treatments could be the result of freezing (crystal formation).
Author Response
Response to Reviewer 2 Comments
Reviewer 2
Submitted manuscript is very well written and pleasant to read. The topic undertaken by the authors is very relevant as problems relating to aging society are becoming more and more important. The introduction is properly written and leads well the reader to the topic. Materials and methods are described accurately enough. The results are clearly presented and the discussion is lead well. I have only few minor remarks (please see detailed comments) that do not influence the overall value of the manuscript. Conclusions are supported by the results, therefore submitted manuscript can be recommended for publication in Processes.
Detailed comments:
- Line 400-408 why values for non-enzyme processed sample are not provided? Moreover why it is implied that texture modification resulted in changes to TMA, as it could be also related to steam treatment.
Response: Thank you for your attentive reading and comment. This is our mistake, so we added the TMA value of non-enzyme treated product in the revised manuscript. Also, we deleted the sentence “the texture modification process significantly inhibited the development of off-odors such as TMA, compared to raw fish.”
On the other hand, we could not find studies describing for the analysis of TMA content of superheated steam treated fish. Despite this, our previous study did report that superheated steam treated fish show TMAO levels much lower than the acceptable limit. Taking into consideration the relationship between TMAO and TMA, it is assumed that superheated steam treatment does considerably affect the TMA content of texture-modified yellowfin sole and non-enzyme processed product.
Mohibbullah, M., Won, N. E., Jeon, J. H., An, J. H., Park, Y., Kim, H., ... & Choi, J. S. (2018). Effect of superheated steam roasting with hot smoking treatment on improving physicochemical properties of the adductor muscle of pen shell (Atrina pectinate). Food science & Nutrition, 6(5), 1317-1327.
Thus, we have cited this study in the revised manuscript to better discuss the TMA value changes we registered and to possibly relate them to superheated steam treatment.
- Line 421-422 please rephrase, sentence to colloquial for research article.
Response: Thank you for pointing out this language slip. We revised the sentence (line 430) to “These results suggest that texture-modified yellowfin sole contains a quite balanced amino acid dietary profile.”
Furthermore, we re-checked and revised the whole manuscript for better academical language, formality, and clarity.
- Line 454-494 in my opinion the “reference” results and discussion related to that should be deleted. It is pointless and proves almost nothing. I suggest just discussing the nutritional value of texture modified fish similarly to protein composition and just referencing it to sum of acids form cited study.
Response: Thank you for this thought; after careful consideration, we have deleted the “reference” data from Table 8 and the related sentences from the main text of the revised manuscript, respectively. Furthermore, we added some considerations about the nutritional value of fatty acids in texture-modified yellowfin sole (lines 478-483).
- Line 498-502 repetition of data, please delete.
Response: Thank you for pointing out this redundancy; we have now deleted the repeated information, as it was already presented in Table 9.
- Line 583-590 similar decrease in hardness after storage for all treatments could be the result of freezing (crystal formation).
Response: Thank you for your suggestion; we further consulter the literature and revised the paragraph to “All storage groups showed a similar decrease in hardness after storage days and this is considered the result of freezing. Dalvi-Isfahan et al. (2016) [57] reviewed some studies and concluded that the tenderness of meat increases with freezing and thawing, as the decrease of hardness for frozen meat is related to the loss of structural integrity caused by ice crystal formation (Leygoni et al. 2012) [58].” (lines 573-577)
As you can see, we also added the relevant references related to that.
As we believe this is an important line of reasoning for our discussion, thank you again for pointing this out! Our manuscript certainly benefited from your attention.
Thank you for your valuable comments on our manuscript. We have modified our manuscript according to your suggestions and we ask that the revised manuscript be re-examined and considered for publication.
Round 2
Reviewer 1 Report
Dear authors,
Thank you for clarifying some issues, although I still have some comments:
1-6-9. I understand that, in this case, pH and T are not your options. However, instead of performing a preliminary study of enzyme ratio, you could study “enzyme ratio” versus “enzyme concentration” over time. When you perform a CCRD, you are not only studying linear and quadratic effects of variables but also the interaction between them.
Many studies have been using “time” as an independent variable, but it do not mean it is a good strategy in kinetical study. And, because of this, we should take care before continuing disseminating it. Even not comfortable, I will reject the whole study, but take care next time.
2. If you are saying that only linear terms (x1 and x2) are statistically significative, and you remove other terms, a planar surface is expected. Curvature is due to quadratic terms. Interaction terms (i.e., x1x2, x1x3, or x2x3) would also cause some inflection.
You can keep the non-significative terms you consider necessary by explaining your reasons. However, in this kind of process, you could consider 90% confidence level (then x2^2 would be significative).
3. Ok
4. Ok, but I’ve noticed you had deleted “<” from all cases. Please note you should write “<0.001” if the p-value is under “0.001”, but writing “<0.013” or “<0.079” do not make any sense. Please, check again p-value typing (it is still “P-value” there)
5. Ok (or write it in another way)
7. Ok
8. Ok
Author Response
Letter responding to the reviewer’s comments for processes-1174130
Reviewer 1
1-6-9. I understand that, in this case, pH and T are not your options. However, instead of performing a preliminary study of enzyme ratio, you could study “enzyme ratio” versus “enzyme concentration” over time. When you perform a CCRD, you are not only studying linear and quadratic effects of variables but also the interaction between them.
Many studies have been using “time” as an independent variable, but it do not mean it is a good strategy in kinetical study. And, because of this, we should take care before continuing disseminating it. Even not comfortable, I will reject the whole study, but take care next time.
Response: Thank you for your comment and we considerably agree with your opinions. In response to your comment, we have added “This study has consistently focused on investigating the responses that differs from enzyme concentration over time. Further researches are needed to put enzyme ratio as in-dependent variable to the CCD.” to the revised manuscript. On the next research, we will try to take your suggestions and perform the experiment in accordance with the improved design.
- 2. If you are saying that only linear terms (x1 and x2) are statistically significative, and you remove other terms, a planar surface is expected. Curvature is due to quadratic terms. Interaction terms (i.e., x1x2, x1x3, or x2x3) would also cause some inflection.
You can keep the non-significative terms you consider necessary by explaining your reasons. However, in this kind of process, you could consider 90% confidence level (then x2^2 would be significative).
Response: Thank you for your comment. We basically understand what your comment means. As you mentioned, we keep the all coefficients in the model because they are necessary for explaining that this study is purposed to be practical research for actual production line. We will keep taking care this point on the next research.
- 4. Ok, but I’ve noticed you had deleted “<” from all cases. Please note you should write “<0.001” if the p-value is under “0.001”, but writing “<0.013” or “<0.079” do not make any sense. Please, check again p-value typing (it is still “P-value” there)
Response: Thank you for your comment. We have carefully rewritten “<” symbol according to the p-value (0.05) in the Table 3 to the revised manuscript.
Thank you for your valuable comments on our manuscript. We have modified our manuscript according to your suggestions and we ask that the revised manuscript be re-examined and considered for publication.
Author Response File: Author Response.pdf
