Tropical Red Fruit Blends: The Effect of Combination of Additives on Foaming, Drying and Thermodynamic Properties
, Alexandre José de Melo Queiroz 2, João Paulo de Lima Ferreira 2, Francislaine Suelia dos Santos 2, Carolaine Gomes dos Reis 2, Lumara Tatiely Santos Amadeu 2, Antônio Gilson Barbosa de Lima 3, Josivanda Palmeira Gomes 2,*, Wilton Pereira da Silva 2, Patricio Borges Maracajá 4 and Caciana Cavalcanti Costa 2Round 1
Reviewer 1 Report
The authors explore an important area of research, the drying and powdering of fruit pulps, which may open up excellent opportunities for combining the beneficial phytonutrient and sensory properties of different blends, with longer shelf-life. Drying in a foam layer is an efficient, simple and inexpensive process that results in high quality dry products. In their research, blends of three tropical fruits (acerola, guava, pitanga) are being investigated to determine the drying kinetics and thermodynamic properties of products treated in different ways.
The title is sufficiently detailed and precise. The Abstract is informative but too long, it would be worth shortening. Key words are appropriate.
In the introduction, it is necessary to present previous international results of the drying method used in this research, with a more detailed comparison with other methods. The definition of the objective is appropriate.
Some parts of the text need to be clarified, such as "Suw.b.equently" and "aw.b.ence".
Subsections 2.1. Material; 2.2. Blending; 2.3. Foam formulations; 2.4. Foam Physical Properties; 2.5. Drying kinetics; 2.6. Effective Diffusivity; 2.7. Thermodynamic properties; 2.8. Statistical analysis are adequate, it would be worthwhile to add the formula for the (R2) value to the manuscript.
In the preparation of the blends, the fruits were added in a 1:1:1 ratio. What was the reason for this? It would be good to explain this in the manuscript. Why were these three stabilisers (arabic gum, guar gum, gelatine) chosen?
The foams were analysed over six mixing times (5, 10, 15, 20, 25 and 30 min) for density, volume expansion, stability and porosity. They were dried in forced-air ovens at temperatures of 50, 60, 70 and 80 °C with a layer thickness of 0.5 cm. Justification of the chosen layer thickness is also required. The mathematical models used for the experimental data on drying kinetics are appropriate.
The tabular presentation of the physical properties of the foam is adequate, but the title is inappropriate: Table 3. Average density values of the foams of the formulations (E1, E2 e E3) as a function of mixing time.
Table 6 is too large and I suggest that it be included as supplementary material.
One of the most important results of this study is that the researchers have convincingly demonstrated, using three different metrics (R2, DQM, ?2), that their models fit satisfactorily to experimental data on drying kinetics and can therefore be used to predict drying kinetic curves. Of the seven drying models tested, the Page model showed the best fit.
The drying kinetic curves of the foam layer are illustrative.
The thermodynamic results need to be compared with other international results.
The conclusion section is fair and accurate, it would be worthwhile to include further research in this section.
Author Response
Dear reviewer
The authors would like to thank you for correcting the manuscript, the requested revisions have been carried out.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments:
There are grammatical mistakes somewhere.
Somewhere, too long sentences are made. So, general English language improvement is needed.
Line 34 (Abstract): Please write properly ‘Suw.b.equently’
Line 37-39: Please rewrite with proper sense
Line 44: Please write properly‘Gibw.b. free energy’
Line 59: Please check spellings for ‘componentes’
Line 59-62: Please properly write, removing grammatical errors
Line 74: ‘so that’ does not make sense here. Please write properly.
Line 92: Please rewrite properly ‘were used’ in the beginning of sentence
Line 99-102: Please write the sentence properly. Also check ‘aw.b.ence’
Some recent and relevant citations may be added such as:
· Applications of biosurfactants in dairy industry In Applications of Next Generation Biosurfactants in the Food Sector. https://doi.org/10.1016/B978-0-12-824283-4.00024-1)
Author Response
Dear reviewer
The authors would like to thank you for correcting the manuscript, the requested revisions have been carried out.
Author Response File: Author Response.pdf
Reviewer 3 Report
The study focuses on the effects of the addition of albumin (as a foaming agent) and stabilisers (xanthan gum, guar gum, and gelatine) to fruit blends on foaming, drying, and thermodynamics properties. The study lacks novelty, and the findings are preliminary. The manuscript is not ready for publication since it has a lot of spelling and grammatical mistakes.
Some general comments on the study:
1. Why were 6% albumin and 1% stabiliser used in this study? Are these based on a previous study, or are these findings just preliminary data? A better experiment design should include various levels for these two additives (Line 221, 226). The use of fixed % for albumin and stabiliser is the biggest flaw of this study.
2. Without optimisation in this study, it is not suitable to claim the best/optimal mixing time (Line 39, 212). The lack of an optimisation tool is also one of the flaws of this study.
3. Ripe fruits were used (Line 99). Please define in terms of months.
4. The maximum speed is not properly measured. Will the maximum speed (Line 115) of the domestic mixer influence the results/findings of this study? If yes, can this experiment be replicated?
5. How do the authors ensure the thickness is 0.5 cm?
6. Is it common to use 80°C for drying? Will it be too high? Will it cause any detrimental changes in the heat-sensitive compounds in the fruits, e.g., vitamin C and polyphenols?
7. What is the rationale for testing all the seven mathematical models, since it was stated (in Line 341-351) that the Page model is the best?
8. Line 354 and Fig. 2: How do the authors observe the different behaviour of the formulations during drying?
Some specific comments on the manuscript:
1. I strongly suggest the authors send the manuscript for professional proofreading services. Get assistance from a professional instead or a native English speaker.
2. The abstract is too lengthy. Line 21 to 27 is about on introduction. Replace these sentences with the rationale of the study.
3. Line 33: Replace “30min” with “30 min”. Space between number and unit, except for %. Please check throughout the manuscript for similar mistakes, e.g., Line 105.
4. Line 37-39: Restructure. Same issue with Line 43-44, 59-62.
5. Line 42: Significant?
6. Line 44: Spelling mistake. Please check throughout the manuscript for spelling mistakes, e.g., Line 59, 92, 99, 185, 201, 225, 237, 452.
7. Line 45: Why do the authors need to redefine E2 again? The sample names were redefined multiple times in the manuscript. I suggest authors define these names twice: in the abstract and in the methodology.
8. Keywords: Use common names instead of scientific names.
9. Line 97: Authors need to provide more information on the gelatine used, e.g., Bloom value, source, and type of gelatine.
10. Line 106: Please check the freezer temperature.
11. Line 107: How was the thawing process done?
12. Line 111-112: Please check.
13. Line 108: Please provide the complete equipment info (brand, model, city, country). Please check throughout the manuscript to ensure complete equipment info was provided.
14. Line 133: How can we calculate the stability? The equation given is for the drainage ratio. The authors should explain using foam stability rather than drainage ratio. Fig. 1 should be constructed for foaming stability.
15. Line 145: What are the pre-determined time intervals?
16. Equation 4: Please check.
17. Line 203-205: Authors only stated the results and results from other existing studies. However, the authors did not discuss (1) the reason for the trend observed with mixing time for E1 and E3, (2) the reason for the trend observed with mixing time for E2, and (3) the reason for the difference in the trend observed between E2 with E1 and E3. Similar comments for other properties (e.g., Line 233-235).
18. Line 228-230: The densities reported here are >0.79 g/cm3. Are these similar to the findings in this study? How do the authors relate this statement to the finding in this study?
19. Line 245: The reference used is from 1999. Avoid using references over 10 years, as they are hard to confirm the validity of the findings reported.
20. Line 259-261: Avoid having a single sentence as a paragraph.
21. Line 289-292: Restructure
22. Line 298-301: Since optimisation was not conducted, the claim made is not valid.
23. Table 5: Why were standard deviations not provided? What is E1/50?
24. Table 5: Water content in w.b. and d.b. were provided. Please provide both equations used to calculate water content in w.b. and d.b. Also, please provide the equation to calculate powder yield in the methodology.
25. Line 322: Lack of discussion.
26. Table 6: I would suggest authors only provide data from the Page model. Data for other models can be provided as supplementary data.
27. Line 325: Which table?
28. Line 347-351: Restructure
29. Fig. 2: Please identify which figures are for E1, E2, and E3.
30. Line 390-396: Restructure
31. Line 395: What is the meaning of constated? Please reconfirm the Ea value.
32. Line 408-410: Why do authors think it is necessary to redefine E2 and E3?
33. References: Please check the format. There are some inconsistencies in the format for the references, e.g., the abbreviation for the journal name (Line 483, 494, 496, 498, 513, 515, 517, 522, 524, etc..), scientific name (Line 503, 516, 519, 536, 557, etc..), authors’ name (Line 510, 562).
Author Response
Dear reviewer
The authors would like to thank you for correcting the manuscript, the requested revisions have been carried out.
Author Response File: Author Response.pdf
Reviewer 4 Report
The present research deal with effect of foaming agents on foam mat drying characteristics. Foam mat drying is an efficient drying method with several advantages such as increased drying rate due to higher surface area, energy efficiency and cost effectiveness. Research methodology is well designed and results are explained sufficiently. The following comments are suggested for further improvement of the manuscript.
Abstract
Line 21 – 27 is unnecessary in introduction. Authors shall explain this within two lines.
Abstract is extensively written with many sentences from introductory section, please revise.
Line 34: “Suw.b.equently” – correct it.
Introduction
Line 53-57: Sentence is too long to read.
Line 74: “So that”, replace with “Therefore”.
There should be one paragraph on importance of fruits (Acerola, guava and pitanga) used in this study. Authors shall write this in terms of their nutritional composition and health benefits.
Review of literature is not written. There shall be a separate paragraph on previous study on use of foam mat drying and effect of processing parameters on drying rate and correlate it with expected new knowledge.
Authors shall write a statement of knowledge gap and define the hypothesis.
Materials and Methods
Line 92: Sentence is incomplete.
Line 99: “aw.b.ence”, correct it.
Results
Line 201: “25 e 30 min”, correct everywhere.
Line 203-204: Authors stated, “significant increases in density occurred when the duration of mixing times was increased”, however from table 2, the increasing trend in densities was only in the case of E2. Explain this.
Line 206: “E2 e E3”, correct it everywhere.
Table 3: What is the meaning “aA, bB, …”? Write in caption.
Line 260: Explain how the raw material chemical composition in present study is affecting the volumetric expansion.
Authors have explained the obtained numerical data in term of effect of different foaming agents. However which properties of Arabic gum, guar gum and gelatin are responsible for these effects and difference between these materials shall be discussed.
Figure 1: Figure quality can be increased.
Model validation part is missing. Authors shall validate the best fitted model.
Conclusion
Authors shall write about the significance of the study and how these research finding are helpful, industrial applications.
Author Response
The authors thank you for your attention in correcting the manuscript and accepted all requested corrections.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
The authors have amended the manuscript. The manuscript is ready. However, there are still some corrections to be made.
1. Line 157-158: Italic scientific names. Please make sure all scientific names are properly written.
2. Line 166: Some additives come in various forms/types/strengths. Could you provide more information on the additives used, e.g. Bloom no. and Type of gelatin, unless the results are the same regardless of the forms//types/strengths?
3. Line 185 & 190-191: Please identify which study the methods were based on. Could you provide more information if it is based on preliminary or unpublished studies?
4. Fig. 1: For the y-axis, reduce the scale to only 2 decimal places. Provide the standard deviation and statistical comparison.
5. Fig. 2: For the y-axis, use "." instead of ",".
6. All abbreviations (including sample names) must be explained/defined in every figure (and table).
7. Please check the format of the references. Use a consistent format and comply with the format of the journal. Check on the scientific name.
Author Response
Dear reviewer
All requested revisions were carried out.
The authors appreciate your help in improving our manuscript. We hope that everything is ok.
