High Pressure Processing Has Variable Effects on Protein-Related and Sensory Properties of Cold and Hot Smoked Rainbow Trout

Round 1

Reviewer 1 Report

The manuscript is generally well written, focusing on an interesting fundamental research point, the effect of high pressure on protein status and general quality parameters on rainbow trout, cold and hot smoked. The research strategy was well planned and executed with care and scientific pertinence.

 

However, the work is somehow lacking a possible more practical application possibility. I can foresee that the real reason to do this work was probably the interest of using high pressure to inactivate microorganisms in the two products studied, since they basically undergo no microbial inactivation step, particularly the cold smoked, while the hot smoked might have suffered some inactivation while being smoked, to improve the microbial safety of the two products. If this is the case, the author should state this and discuss this point in the in the scope of the paper. If not, the authors should indicate and discuss this is a possibility. This would increase the value of the paper in my opinion.

 

 

I suggest the authors indicate the water activity of both products studied (cold and hot smoked rainbow trout), because this parameter might be different in the two products and should have an influence on the results obtained and should be useful to explain and discuss the results observed.

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

This paper describes the high pressure treatment of hot and cold smoked rainbow trout. The effect of the high pressure treatment has been evaluated by biochemical methods and also by sensory panels.

High pressure treatment is a green alternative for food processing. There is a need for studying pressure induced changes in composition and sensory values. The topic of the paper is up to date and it should be published.

But there are some questions to be clarified before:

1. P2L53 The effects of pressure on proteins is shortly mentioned here. I think a more detailed description would be desirable. The unfolding, dissociation etc. need different pressure ranges, and some of the changes like aggregation are observable only after pressure treatment. Some references would also be useful for this sentence as well.

2. P2L69: What do the authors mean by "changes in amino acid profile"? Actually pressure is not able to disrupt covalent bonds, therefore the amino acids cannot be modifies by pressure. Even their sequence annot be modified, since it would need breaking covalent bonds.

3. P3. L99-109: Why did the authors use samples for in vitro digestion and for consumer evaluation from different sources?

4 P3L113:  If the pressure was increased really with 1 MPa/s, 10 minutes were needed to reach 600 MPa. Although low pressurizing rate is good for avoiding adiabatic heating, 10 minutes seems to be long in comparison with 3 minute holding time. 

5. same position: depressurizing in less than 1 sec would lead to huge adiabatic cooling effect. Did the authors observe freezing of the sample due to this effect? If yes, how could this influence the results?

6. P6 Table 1: In the caption should be mentioned if it is the standard error or standard deviation or something else (confidence interval) is given in the table.

7. P8Table2: In line "soft" and row "CSRT-400" the  letter "c" is obviously a mistake, since no other c is in this row.

8. P10 Table 4. Why did the authors show only the result of the PCA analysis for the CSRT and not for HSRT?

9. How can I see the effect of the pressure from the PCA analysis? Had the pressure no effect?

10. P12L408 "release of free amino acids by HPP" It is unbelievable for me since high pressure breaks only secondary and not primary bonds. (See remark 2!)

 

I hope the authors can answer these questions and make appropriate changes in the manuscript. After such correction it will be suitable for publishing.

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The MS is now in condition to be published.

 

Author Response

Dear Reviewer,

we thank the Reviewer for the recommendation of publication.

On behalf of authores,

Jenni Korhonen

Reviewer 2 Report

The answers from the authors are satisfactory.

I have two comments:

5. It is quite unbeliavable that there was no adiabatic coolig during the fast depressurzation, but I accept that the prolduct was not frozen.

 

8. The reason for not publishing the PCA results for CSRT samples should be menitoned shortly in the text!

 

After this correction the manuscript is acceptable.

Author Response

Dear Reviewer,

thank you for the comments. We have now added the reason for not publishing the PCA results for CSRT samples, and it is mentioned in the text in lines 248-250 and on line 491.

We thank the Reviewer for recommending the manuscript for publication.

On behalf of the authors,

Jenni Korhonen