Effects of Heat Treatment and Tea Polyphenols on the Structure and Properties of Polyvinyl Alcohol Nanofiber Films for Food Packaging

Round 1

Reviewer 1 Report

The whole manuscript needs to be checked for grammar (especially abstract, introduction and results). Need to rewrite a lot. Page 2. Line 72-73. “Thus, recent research has focused on the development of physical crosslinking and polymer blending, which are safer, more convenient and lower cost approaches compared to others.”

Compared to what? The whole paragraph consisted of polymer blending, mixing inorganic materials, and cross linking. Authors need to properly categorize safer and dangerous methods. Also, need a complete grammar check.

Introduction - The authors need to give a brief overview of the natural antioxidant tea Also, some description on other natural antioxidants. (apart from a single sentence which mentions about tea phenols Line 81-82) Need to give the full form of CS (line 46 page 2) Why did you use a crosshead speed of 20mm/min. Have you met any of the ASTM standards? Is the initial distance here means gauge length? Please explain in a better way. Line 218 Page 6. Where is PVA/TP-8:2 in FTIR spectra figure? Line 234-240. The study cites the increase in sample crystallinity by heat treatment and the introduction of tea phenols and compares them with the results of water resistance and mechanical strength or elongation (line 286). Please add the crystallinity index values for the samples using XRD or any other method. This could give better comparison with results. Figure 5. Please add the stress-strain curves for different set of samples from tensile testing. This could give an idea on the toughness which is very important for packaging.

Author Response

Comments and Suggestions for Authors 1：

The whole manuscript needs to be checked for grammar (especially abstract, introduction and results). Need to rewrite a lot. Page 2. Line 72-73. “Thus, recent research has focused on the development of physical crosslinking and polymer blending, which are safer, more convenient and lower cost approaches compared to others.”

Re: The abstract, introduction and results and some incorrect descriptions of the manuscript were revised. Thanks.

 

Compared to what? The whole paragraph consisted of polymer blending, mixing inorganic materials, and cross linking. Authors need to properly categorize safer and dangerous methods. Also, need a complete grammar check.

Re: The grammar has been revised throughout. Thanks.

 

Introduction - The authors need to give a brief overview of the natural antioxidant tea Also, some description on other natural antioxidants. (apart from a single sentence which mentions about tea phenols Line 81-82).

Re: The background of TP was added. Thanks.

 

Need to give the full form of CS (line 46 page 2)

Re: Done. Thanks.

 

Why did you use a crosshead speed of 20mm/min. Have you met any of the ASTM standards? Is the initial distance here means gauge length? Please explain in a better way.

Re: We corrected the wrong description. Thanks.

 

Line 218 Page 6. Where is PVA/TP-8:2 in FTIR spectra figure?

Re: Fig. 3 was replaced. Thanks.

 

Line 234-240. The study cites the increase in sample crystallinity by heat treatment and the introduction of tea phenols and compares them with the results of water resistance and mechanical strength or elongation (line 286). Please add the crystallinity index values for the samples using XRD or any other method. This could give better comparison with results.

Re: Due to the limited experimental conditions, the XRD data cannot be obtained temporarily. So the inaccurate description has been removed. Thanks.

 

Figure 5. Please add the stress-strain curves for different set of samples from tensile testing. This could give an idea on the toughness which is very important for packaging.

Re: Added. Thanks.

Reviewer 2 Report

The authors have studied the effect of heat treatment and tea polyphenols on polyvinyl nanofiber films prepared by electrospinning.

Title: Actually from the title it looks that the manuscript regards only the influence of heat on films. So please change the title. 

Materials and methods: Besides film color, the authors should also study the film transparency and how they act as barrier for the UV for a food sector application (Please see the paper : Glycerol-plasticized films obtained from whey proteins denatured at alkaline pH_ Abdalrazeq et al. 2019)

Antimicrobial experiments: which is the weight of a film? A rectangle of 20 mm X 20 (and it shoud be a square) mm seems to heavy to be 100 mg)

Morphology analysis: Did the authors show the cross-section or the surface of the films? Fig 1 what is written on  the y-axis? 

In Fig. 5 and 7 why  it wasn't study the effect of heat treatment on the investigated characteristics? 

Introduction : the authors can review the following papers: Sagneli et al. (2017) All-natural bio-plastics using starch-betaglucan composites. Carbohydrate Polymers 172, 15 Pages 237-24. 

 

Author Response

Comments and Suggestions for Authors 2：

The authors have studied the effect of heat treatment and tea polyphenols on polyvinyl nanofiber films prepared by electrospinning. Title: Actually from the title it looks that the manuscript regards only the influence of heat on films. So please change the title.

Re: The title was changed. Thanks.

 

 

Materials and methods: Besides film color, the authors should also study the film transparency and how they act as barrier for the UV for a food sector application (Please see the paper : Glycerol-plasticized films obtained from whey proteins denatured at alkaline pH_ Abdalrazeq et al. 2019)

Re: PVA/TP films have no barrier for the UV, so only the film transparency and the reference were added. Thanks.

 

 

Antimicrobial experiments: which is the weight of a film? A rectangle of 20 mm X 20 (and it shoud be a square) mm seems to heavy to be 100 mg)

Re: Yes, you are right. Some inaccurate descriptions were modified. The weight of each sample for antimicrobial experiment is 100 mg. Thanks.

 

Morphology analysis: Did the authors show the cross-section or the surface of the films? Fig 1 what is written on the y-axis?

Re: The typical cross-section of the film was added and Fig. 1 was revised. Thanks.

 

In Fig. 5 and 7 why  it wasn't study the effect of heat treatment on the investigated characteristics?

Re: Our purposes is to design barrier coatings in food packaging have the ability to block water, we found that water resistance was improved by heat treatment, indicating that the nanofiber films without the heat treatment would not suitable for food packaging. Hence, the mechanical properties and antibacterial efficiency of the nanofiber films only with heat treatment were explored. Thanks.

 

Introduction : the authors can review the following papers: Sagneli et al. (2017) All-natural bio-plastics using starch-betaglucan composites. Carbohydrate Polymers 172, 15 Pages 237-24.

Re: Added. Thanks.

Round 2

Reviewer 1 Report

Please go through minor grammar mistakes and also fine/minor spell check required