Impact of Zinc Oxide Nano Particles, Poly Vinyl Alcohol, and Natural Polymers on Quality Characteristics of Nanocomposite Film

Round 1

Reviewer 1 Report

This work deals with the effect of ZnO nanoparticles addition to a bio-polymeric mixture on the phisico-chemical properties of achieved biodegradable films. Although the topic is worth investigating, on my behalf there are several flaws that cannot be neglected and hence I suggest rejection of the paper in its present form.

Nevertheless, I would like to leave some suggestions to the authors which might be helpful while proceeding with another submission elsewhere:

Major comments:

- There are several mistakes (including punctuation, grammar, and format) throughout the whole manuscript. Please check the whole file and correct mistakes;

- I suggest the authors to employ a commercial polishing service to improve the quality and readability of the English language.

- Information is almost always disconnected so that it becomes hard to understand the points.

- The title must be revised. It does not clearly embodies the aim of this work.

 

Specific comments to different manuscript sections:

"Abstract" section

Line 12: which is the object of the "modification"?

Lines 10 - 25: the abstract must be rewritten following this order --> background, aim of the work, materials and methods, results, and conclusion.

Lines 22-24: it would be better to shift the content of these lines upward, as the main substrates must be mentioned at the beginning for clarity purposes.

 

"Introduction" section

Line 30: is there any reason for which the target of this study is only milk?

Lines 34 - 36: what about the safety issues related to the presence of nanoparticles within packaging materials?

Lines 42 - 43: "that can act as an excellent oxygen barrier property", this is true only at very low levels of RH.

Lines 30 - 66: overall, it seems that the introduction section lacks of flowing and readability, as well as the aim and novelty of this work are not suitably justified.

 

"Materials and Methods" section

 Line 70: which is the amount of proteins in either WPC or WPI?

Paragraph 2.1: cities/nations of cited companies selling products/equipment must be reported.

Line 75: why did the authors choose this packaging configuration? Does it emerge from optimization in previous studies?

Lines 141 - 142: what do the authors refer to when saying "six measurements were taken at different points..."?

Line 144: the method for water permeability measurement must be reported in case one would replicate the experiments.

Line 158: which was the width of the tested strips? Did the authors join any ASTM standard? Moreover, the authors must be aware of the fact that using a force as unit of measurement could not enable comparison among considered samples in terms of tensile properties, since their own thicknesses play an important role in the behavior under mechanical stress.

Lines 159 - 161: which kind of probe was used to pierce the samples?

Lines 166 - 168: this part sounds awkward and unclear.

Paragraph 2.7.2: which was the p-value the authors set to perform the statistical analysis?

 

"Results and discussion" section

In general, no explanation neither argumentation is inferred in the whole chapter. This aspect dramatically curbs the quality of the paper.

Figure 2: the legends within this figure are redundant (either at the top or at the bottom)

Lines 186 - 187: which role? please, motivate this sentence.

Figure 3b lacks of the unit of measurement for the y-axis.

Paragraph 3.6.2: considering a previous comment, it would have been better to express the results of the tensile tests in MPa rather than in N in order to better elucidate the role, if any, of ZnO nanoparticles on the mechanical properties of nanocomposite films

Figure 6: it is quite tricky to follow the statistical analysis in this histograms chart.

In my opinion, the conclusion section is a "mere copy" of what the authors have collected within the paper, without any personal hint on how the work can be improved, as well as on which could be the food categories this kind of packaging is suitable for. 

Author Response

PLEASE SEE THE ATTACHMENT 

Author Response File: Author Response.pdf

Reviewer 2 Report

In the present work, the author reported the preparation of nanocomposite film using corn starch, whey protein concentrate, whey protein isolate, carrageenan, PVA, glycerol and ZnO nanoparticles. The following issues have to be addressed:

• In all manuscript, keep the same format for “poly vinyl alcohol”, because it is write as “Poly Vinyl Alcohol” or “poly vinyl alcohol” or “Polyvinyl alcohol” (line 352).

• At Introduction, specify also other type of nanoparticles used for synthesis of nanocomposite film to highlight the chosen Zinc Oxide (ZnO).

• At “3.1. Properties of different type of slurries”, remove 3.1.1. Viscosity, 3.1.2. pH, etc.

• When describe this chapter, start with: The properties of different type of slurries such as viscosity, pH, PDI, Zeta Potential, and  Z-Average are presented in Figure 2”.

• Modify “Figure 2. Properties of different types of slurries used for film formation.” with “Figure 2. Properties of different types of slurries used for film formation: (a) viscosity, (b) pH, (c) PDI, (d) Zeta Potential, and (e) Z-Average.”

• Remove the name Fig. 2A, Fig. 2B, etc, inside of each figures.

• In case of Figure 2A, correct the abbreviation for samples (a, b, c).

• Move the Figure 2 after the discussion for Z-Average (line 210).

• At “3.2. Properties of different type of films”, correct the chapter like as chapter 3.1.

• When describe this chapter, start with: The properties of different type of films such as film thickness, light transmittance, water activity, water vapor permeability (WVP), film solubility, tensile strength, and puncturing strength are shown in Figure 3”.

• Move the Figure 3 after the discussion for Puncturing strength (line 268)

• At “3.3. Colour”, correct the chapter like as chapter 3.1.

English improvement is required. Some examples but not all are as the following:

Page 2, line 78, modify “which corn starch @2.5%was” with “which corn starch (2.5%) was”

Page 3, line 102, modify “drying of the film. [Fig 1A &Fig 1B)” with “drying of the film (Fig. 1A & Fig. 1B).”

Comments for author File: Comments.docx

Author Response

PLEASE SEE THE ATTACHMENT 

Author Response File: Author Response.pdf

Reviewer 3 Report

In my opinion the article needs major improvements.

Some examples of improvements are presented below:

-          The abstract should not have more than 200 words

-          Row 17 – Please explain d-nm.

-          Row 21 - I suggest to replace the „Gram +ve” with Gram positive. „Bacillus cereus”  in italic please.

-          Row 22 - I suggest to replace the „Gram -ve” with Gram negative. „Escherichia coli”  in italic please.

-          Keywords: synthetic - I suggest to use the lowercase n. I suggest removing the dot after the PVA acronym.

-          Row 64 - I suggest removing the dot after weight. I suggest checking the entire article, looking at the punctuation.

-          Acronyms/Abbreviations should be defined only when it appears for the first time in the text. Then only the acronym is used in the text.

-          Row 98 – Ultrasonicator - Is capital U necessary?

-          Row 99 - demonstrated by Sivakumar et al. [16,17] - I suggest you pay attention to the second square bracket, and punctuation as well.

-          Row 99 - film. [Fig 1A &Fig 1B) -  I suggest you pay attention to the punctuation and the spaces between words. Correct would be: film (Figures 1a and 1b).  Please check the punctuation throughout the article.

-          Row 103 - Please use acronym.

-          Rows 115 , 119, 125 – Is @ necessary?

-          Row 130 – nanocomposite (optimized).

-          Please check the spaces between words throughout the article.

-          Figure 2A. Please use the SI unit of viscosity.

-          Is pH so important? I don't see changes that exceed 0.5 pH units.

-          Figure 2 should be rearranged (colors, scale, borders, uppercase letters - lowercase letters?, d.nm?, etc.)

-          Figure 3 should be rearranged (scale, borders, uppercase letters - lowercase letters?, Light transmittance units, etc.)

-          Row 130 - Please check the spaces between words throughout the article. I suggest you pay attention to a_w.

-          Figure 4 should be rearranged.

-          Row 292 - Scanning Electron Microscopy

-          Figure 5a – Quanta 10 μm? Should be better 50 μm.

-          Figure 7 is not understood (which is a, which is D). Please pay attention.

-          References should be prepared in accordance with the requirements of the journal.

Author Response

PLEASE SEE THE ATTACHMENT

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I am glad to recognize the efforts put in place by the authors in improving the quality and readability of the paper according to the suggestions made by the Reviewer. Anyway, still some minor issues are present and need to be solved prior to accept the paper for publication.

- Paragraph 2.6. The equation for the calculation of WVP must be numbered.

- The authors have to number the subsections related with the properties of different type of slurries (i.e., 3.1.1. Viscosity, 3.1.2. pH, etc.). The same comment applies for the properties of films (3.2.1. Film thickness, 3.2.2. Light transmittance, etc.)

- Figure 2: there's a superposition between error bars and letters expressing statistical differences.

- Figure 3: are the authors sure that the WVP of composite + PVA is significantly sifferent from that of the bare composite? Moreover, also in this case there is overlapping between error bars and letters expressing statistical differences.

- Figure 4: for clarity purposes, sample legends must be placed above the x-axis.

- Conclusion section: which would be the difficulties in bringing this technology to industrial scale?

 

 

Author Response

PLEASE SEE THE ATTACHMENT

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Sirs,

The manuscript was improved and it can be published in this form.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

In my opinion, the article should be published.

However, relate to:

-          Please write the names of the microorganisms either using the full name (e.g. Bacillus cereus) or the short one (e.g. E. coli).  (Abstract)

-          Please explain MAC

-          I suggest you pay attention to the punctuation and the spaces between words (e.g. of significance. (p <0.05). Is the point after signficance necessary?; 3.4. Scanning Electron Microscopy(SEM) o

-          In the name of figures 5 and 6 you have a dot at the end, but in the others you don't.

Author Response

PLEASE SEE THE ATTACHMENT

Author Response File: Author Response.pdf