Degradation Kinetics of Betacyanins during the Pasteurization and Storage of Cactus Pear (Opuntia dillenii Haw.) Juice Using the Arrhenius, Eyring, and Ball Models

Round 1

Reviewer 1 Report

Overall, the manuscript is well-written and the authors managed to show the relevance of the used models to describe the thermal degradation of betacyanins from cactus pear (Opuntia dillenii Haw.) juice but several matters need to be further addressed in order for the manuscript to be accepted.

1. Regarding the English Grammar:

Some suggestions were made to the authors and these are shown in red.

Check your English Grammar properly.

• Use the forms “a”, “an” or “the” in order to define the word. Remember, in order to use A, AN, and THE properly, you must know whether or not a noun is a Count or Non-Count Noun.
• Check each verb to see if it has the right form and also check the tenses you want to use. Pay attention which tense you want to use if you have present tense for example, stick to this tense throughout the whole sentence.
• Use the correct form of the verb as requested by the used noun (Pay attention if the noun is countable or not).

2. Materials and methods - 2.2. Quantification of betacyanin.

The authors should state if the used method was adapted from another scientific study and add the corresponding study.

3. The authors determined only the content of betacyanins but it would have been interesting to determine this content compared to the total content of betalains. Furthermore there are several studies out there, who clearly specify the content of betacyanins in regards to the total content of betalains. Another important analysis would be to determine the antioxidant activity and the total content of polyphenols. Please, specify if these matters could be added to the manuscript.

4. Results and discussion - 3.1. Kinetics of Betacynins Degradation and model validation

The authors state a HPLC analysis but they do not provide the chromatographic profile of the juice sample. Also, they specify that three main betacyanins were identified in the juice such as betanin, isobetanin and neobetanin. How were these compounds determined and identified given the fact that very few standards are available nowadays? Please show a chromatogram and state the HPLC method in the Materials and methods part.

5. Why were all three models used to determine the thermal degradation of the targeted compounds when only two would've been suffice? The authors should add a phrase that clearly state the importance of using all three models.

6. Page 8, line 244 - The authors state the determination of betalains which is not the case in this study. Please correct the sentence and if it the case add the reference.

7. Why was Enterococcus faecalis chosen as the reference microorganism? Is it a common microorganism found in a juice sample? Please add this matter to the Introduction and state why is was this type of microorganism chosen. Furthermore, how was the presence of this bacteria determined? No such information is given throughout the whole manuscript.

Author Response

We thank reviewer for the valuable comments to improve the paper.

Answers to the Reviewer

Overall, the manuscript is well-written and the authors managed to show the relevance of the used models to describe the thermal degradation of betacyanins from cactus pear (Opuntia dillenii Haw.) juice but several matters need to be further addressed in order for the manuscript to be accepted.

Regarding English Grammar:

Some suggestions were made to the authors and these are shown in red.

Comment 1:Check your English Grammar properly.

• Use the forms “a”, “an” or “the” in order to define the word. Remember, in order to use A, AN, and THE properly, you must know whether or not a noun is a Count or Non-Count Noun.
• Check each verb to see if it has the right form and also check the tenses you want to use. Pay attention which tense you want to use if you have present tense for example, stick to this tense throughout the whole sentence.
• Use the correct form of the verb as requested by the used noun (Pay attention if the noun is countable or not).

 Answer 1: Thanks for the comments. English Grammar was checked according to the remarks in the whole text.

Comment 21:Materials and methods - 2.2. Quantification of betacyanin.

The authors should state if the used method was adapted from another scientific study and add the corresponding study.

Answer 2: The corresponding reference study was added in text see line 99.

Comment 3: The authors determined only the content of betacyanins but it would have been interesting to determine this content compared to the total content of betalains. Furthermore, there are several studies out there, who clearly specify the content of betacyanins in regards to the total content of betalains. Another important analysis would be to determine the antioxidant activity and the total content of polyphenols. Please, specify if these matters could be added to the manuscript.

Answer 3: We understand your remark, the identification of betacyanins was performed in a previous study [1], however, we think these matters are not relevant in the study. In fact, They will not provide more insight with regard to kinetic modeling which is, as specified in the introduction, the main objective of our paper. We are preparing another paper where the degradation of all specific betacyanin has been monitored. I think that your remark will btaken into account in that study.

Comment 4: Results and discussion - 3.1. Kinetics of Betacynins Degradation and model validation

The authors state a HPLC analysis but they do not provide the chromatographic profile of the juice sample. Also, they specify that three main betacyanins were identified in the juice such as betanin, isobetanin and neobetanin. How were these compounds determined and identified given the fact that very few standards are available nowadays? Please show a chromatogram and state the HPLC method in the Materials and methods part.

Answer 4: These are results come from one of our previous study on the same raw materials [1], where the composition of the samples was determined. Tamba et al, 2019, provided the corresponding chromatogram and also the HPLC method. They identified each chromatographic peak by assigning their visible spectral characteristics in comparison with standard (betanin and isobetanin only) and retention times.

However, Chromatographic method were not used in this present paper, this paragraph just gives information on the sample that come from a previous characterization. For more clarity some precisions were added line 187-192

Comment 5: Why were all three models used to determine the thermal degradation of the targeted compounds when only two would've been suffice? The authors should add a phrase that clearly state the importance of using all three models.

Answer 5: Ball and Arrhenius represent classical approaches even if they are close, they have different implications in terms of thermodynamic. The fact that ball model gives better simulations than the two others which are quite different shows that it was relevant to use 3 models. The difference between the models was specified in the introduction see line 73-82

Comment 6. Page 8, line 244 - The authors state the determination of betalains which is not the case in this study. Please correct the sentence and if it the case add the reference.

Answer 6: Thanks for the comment. Corrections were made see line 244 and 245

Comment 7. Why was Enterococcus faecalis chosen as the reference microorganism? Is it a common microorganism found in a juice sample? Please add this matter to the Introduction and state why is was this type of microorganism chosen. Furthermore, how was the presence of this bacteria determined? No such information is given throughout the whole manuscript.

Answer 7: The choice of Enterococcus faecalis is justified in the material and method line 170-178. Enterococcus faecalis is a common sign of spoilage of food products moreover, it has great resistance to heat treatment. We use the thermal parameters of Enterococcus faecalis available in the literature to calculate the optimal time/temperature combination. Enterococcus faecalis being resistant to temperature, these simulations happen to be “worst-case scenario”. No microbiological analyses were performed.

Reviewer 2 Report

Paper title: Degradation kinetics of betacyanins during pasteurization and storage of cactus pear (Opuntia dillenii Haw.) juice using the Arrhenius, Eyring, and Ball Models described by Joseph Bassama et al.

This study aims to compare the classical empirical approaches (Arrhenius and Ball models) and an approach based on statistical thermodynamics. This paper is interesting and presents some interesting information for the industry.

L 43- betalamic acid

L 83-89 – should be more preciously described, especially: “This study … “ – add some information about plant material, name

L 96 – homogenized – add some more information about equipment, parameters, producer, etc

L 99 – Cactus juice (2 ml)

L 97- After samples were stored at -18°C until the day of the experiment. – what mean, how long?

- the basic information about chemical composition should be described in M&M section

- Table 1 – what mean 65.6(0.5) – what mean 0.5 ? is a standard deviation?

3.2 Model Predictions … – Authors should add more discussion for this section

Fig 4. – how Authors explain that sample stored at 45oC present some fluctuation between 20-20-40 and 50 days during storage – additionally information for this sample because basic trends Authors describe and discussed with literature.

The conclusion section should present some final value which authors propose to used in real industry for storage period and conditions.

Author Response

Answers to the Reviewer 1

This study aims to compare the classical empirical approaches (Arrhenius and Ball models) and an approach based on statistical thermodynamics. This paper is interesting and presents some interesting information for the industry.

Comment 1: L 43- betalamic acid

Answer 1: Corrections were made. See line 43.

Comment 2: L 83-89 – should be more preciously described, especially: “This study … “ – add some information about plant material, name

Answer 2: The paragraph was edited see line 83-90

Comment 3: L 96 – homogenized – add some more information about equipment, parameters, producer, etc

Answer 3: Corrections were made. See line 97

Comment 4: L 99 – Cactus juice (2 ml)

Answer 4: Corrections were made. See line 101

Comment 5:L 97- After samples were stored at -18°C until the day of the experiment. – what mean, how long?

Answer 5: Precisions were added. See line 99

Comment 6:- the basic information about chemical composition should be described in M&M section

Answer 6: We don’t understand what Chemical composition are you asking for ? does it concern the raw material ?? If it is the case, physico-chemical composition of the raw material is presented in table 1 in the result and discussion section. See line 189-197.

Comment 7:- Table 1 – what mean 65.6(0.5) – what mean 0.5 ? is a standard deviation?

Answer 7: 0.5 is the confidence interval at p= 95%

Comment 8: 3.2 Model Predictions … – Authors should add more discussion for this section

Answer 8: Precisions was added to section line 246-250 and 251-252.

Comment 9: Fig 4. – how Authors explain that sample stored at 45oC present some fluctuation between 20-20-40 and 50 days during storage – additionally information for this sample because basic trends Authors describe and discussed with literature.

Answer 9: That’s a good remark however, we do not have a real answer to this question. A statement was added concerning this at line 278-291. We assume this is due to an experimental error on the sample particularly at 40 days of storage because this type of trend was not reported in the literature.

Comment 10: The conclusion section should present some final value which authors propose to used in real industry for storage period and conditions.

Answer 10: The conclusion was edited. See line 215-218.

Author Response File: Author Response.docx

Reviewer 3 Report

Dear Editor,
The manuscript by Bassama concerns degradation kinetics of betacyanins during pasteurization and storage of cactus pear juice. The authors have well studied the kinetic degradation of betacyanins over temperatures ranging from 60 to 90 °C for Cactus pear juice. Also, calculated the rate constant for betacyanins degradation and isothermal kinetic parameters according to Arrhenius, Eyring, and Ball models. These are interesting findings and much attractive to the readers. Therefore the manuscript could be acceptable for Beverages.

Author Response

Comment 1: The manuscript by Bassama concerns degradation kinetics of betacyanins during pasteurization and storage of cactus pear juice. The authors have well studied the kinetic degradation of betacyanins over temperatures ranging from 60 to 90 °C for Cactus pear juice. Also, calculated the rate constant for betacyanins degradation and isothermal kinetic parameters according to Arrhenius, Eyring, and Ball models. These are interesting findings and much attractive to the readers. Therefore the manuscript could be acceptable for Beverages.

Answer 1: Thank you

Round 2

Reviewer 1 Report

The authors answered all of the comments and the manuscript was improved significantly. I still recommend for future studies to always specify the references used for the papers from which the authors might have used the undertaken methods or the results. Nonetheless, I recommend the publication of the article in its current form.