Gelatin- and Papaya-Based Biodegradable and Edible Packaging Films to Counter Plastic Waste Generation

Round 1

Reviewer 1 Report

Manuscript ID: materials-1565772

Gelatin and papaya based biodegradable and edible packaging films to counter plastic waste generation

Jaweria Ashfaq , Iftikhar Ahmed Channa, Asif Ahmed Shaikh, Ali Dad Chandio, Aqeel Ahmed Shah, Syed Sarim Imam, Sultan Alshehri and Mohammed M Ghoneim

 

Comments and Suggestions for Authors

 

In this manuscript, the commonly available household materials such as gelatin, soy protein, corn starch, and papaya are used to prepare cost-effective, biodegradable, and edible packaging film. The material in the manuscript contains relevant information that may be of interest to readers and is suitable for publication. However, the manuscript cannot be published in its current state and needs to be revised. Therefore, I suggest a major revision of the manuscript based on the following comments. In order to increase the quality of the paper and reach the demands of the Materials, it is recommended new measurements.

 

1. The variation in the glass transition temperature (T_g), melting temperature (T_m) and enthalpy (∆H) are best effective indicators of the compatibility, miscibility, and crystallinity of different biopolymers and blends. Show the differential scanning calorimetry (DSC) analysis of edible materials from various constituents to confirm the thermo-mechanical properties of these films.
2. State the characteristics of the nanoindenter (top of the indenter) and calculate the modulus of elasticity of edible films. Show characteristic force vs depth curve for nanoindentation measurement.

The authors write in Section 3.6. HARDNESS -Table S- 2 shows that the inclusion of DSP produces films with reduced surface roughness and hardness due to the enhanced molecular mobility between polysaccharide chains. Where is Table S- 2 and the results for surface roughness? Are there any images obtained from a microscope?

3. The authors have a problem with upper and lowercase letters, space: need to change (Nano hardness (Anton paar nano-indentation hardness tester), with a maximum load of 10.0 Mn, poison ratio is 0.30.), Tulamandi at el[16], Gelatin (blue line), Papaya (red line) and Soy Protein, 40̊C, Ebdible films,  as (nanohardness (Anton Paar nanoindentation, 10.0 mN, Poison ratio, Tulamandi et al. [16],  gelatin (blue line), papaya (red line) and soy protein, 40 °C, edible films, glycerin or glycerol????…

Correct some spelling and grammatical mistakes.

4. The authors write in Section 4. CONCLUSION - The combination of 10 g papaya puree and 9 g gelatin composite films showed extremely significant edible film qualities, according to the results. I suggest performing statistical analysis with these results, to evaluate if there are significant differences or include the standard deviation of the results.

 

 

Author Response

Reviewer No. 1

In this manuscript, the commonly available household materials such as gelatin, soy protein, corn starch, and papaya are used to prepare cost-effective, biodegradable, and edible packaging film. The material in the manuscript contains relevant information that may be of interest to readers and is suitable for publication. However, the manuscript cannot be published in its current state and needs to be revised. Therefore, I suggest a major revision of the manuscript based on the following comments. In order to increase the quality of the paper and reach the demands of the Materials, it is recommended new measurements.

 

1. The variation in the glass transition temperature (T_g), melting temperature (T_m) and enthalpy (∆H) are best effective indicators of the compatibility, miscibility, and crystallinity of different biopolymers and blends. Show the differential scanning calorimetry (DSC) analysis of edible materials from various constituents to confirm the thermo-mechanical properties of these films.

 

Response: Dear Reviewer we are thankful to you for your valuable suggestion, however it is to explain it here that reason we did not perform DSC is because we don’t have access to this particular equipment unfortunately.

 

1. State the characteristics of the nanoindenter (top of the indenter) and calculate the modulus of elasticity of edible films. Show characteristic force vs depth curve for nanoindentation measurement.

Response: Details of the nanoindentator have been added in the revised manuscript and modulus of elasticity and force vs depth curves are also provided in the revised manuscript.

1. The authors write in Section 3.6. HARDNESS -Table S- 2 shows that the inclusion of DSP produces films with reduced surface roughness and hardness due to the enhanced molecular mobility between polysaccharide chains. Where is Table S- 2 and the results for surface roughness? Are there any images obtained from a microscope?

Response: We are very much thankful to reviewer for the valuable suggestions. We have now modified the section 3.6 of original manuscript and added some more discussions and the modified section is highlighted in yellow.

 

1. The authors have a problem with upper and lowercase letters, space: need to change (Nano hardness (Anton paar nano-indentation hardness tester), with a maximum load of 10.0 Mn, poison ratio is 0.30.), Tulamandi at el[16], Gelatin (blue line), Papaya (red line) and Soy Protein, 40̊C, Ebdible films,  as (nanohardness (Anton Paar nanoindentation, 10.0 mN, Poison ratio, Tulamandi et al. [16],  gelatin (blue line), papaya (red line) and soy protein, 40 °C, edible films, glycerin or glycerol????…

 

Response: The authors are once again thankful to reviewers for highlighting the errors and mistakes. The text in the revised manuscript has been corrected as per suggestions of the reviewers.

 

Correct some spelling and grammatical mistakes.

Most of the spelling and grammatical mistakes are rectified in the revised manuscript.

1. The authors write in Section 4. CONCLUSION - The combination of 10 g papaya puree and 9 g gelatin composite films showed extremely significant edible film qualities, according to the results. I suggest performing statistical analysis with these results, to evaluate if there are significant differences or include the standard deviation of the results.

 

Response: In the revised manuscript, no of samples tested for each test, standard deviation and statistical analysis has been added in the relevant sections. We hope this is provides sufficient information to readers.

 

Reviewer 2 Report

Major comments:

1. In the Introduction, the authors present the main findings from a very similar study, regarding “film-forming solutions of various levels of papaya puree, gelatin, and skim soy protein”. Please express the novelty of the current work, emphasizing its innovative character, if any.
2. When detailing the experimental method, it is more convenient and easy to follow if concentrations/ratios are used to express the composition of the samples, rather than grams. Please modify accordingly in text and Table 1.
3. Please add the number of determinations for each sample and the used statistical evaluation method in the FILM CHARACTERIZATION section.
4. The results are merely presented, not properly discussed. Please add possible explanations for the observed changes. Please give an extended discussion on the obtained results, and correlate your findings with previous literature studies and prospective applications.
5. In all graphs and tables please specify the SD, mean value, the number of repetitions, statistical significance.
6. A general check-up and correction of the English language is mandatory! 

Minor comments:

Introduction:

1. “The quality of the food is the most important factor” … for what? Please continue.
2. Please correct/rephrase: “which is atoms regularly found”
3. Reference 16 is actually Tulamandi et.al., not Sridat et al.

Results:

4. Figure 2 title, please correct “Ebdible films”, “(indiacte with black nd red” and add/remove spaces between words.
5. The information from table 2 is redundant.
6. Figure 4 is referenced in the text before figure 3.
7. How were the values from Table 3 calculated? Please define “CA”.
8. In the CONTACT ANGLE section is stated that “Table 3 shows measurements of contact angles for various pure liquids in film samples” but Table 3 from the manuscript refers to “Optical and Barrier Properties of edible films”. Please correct.

Author Response

Reviewer No. 2

Major comments:

1. In the Introduction, the authors present the main findings from a very similar study, regarding “film-forming solutions of various levels of papaya puree, gelatin, and skim soy protein”. Please express the novelty of the current work, emphasizing its innovative character, if any.

 

Response: The authors are very much thankful to reviewer for this valuable comment. The novelity of this work has been explained in the revised manuscript. However, we briefly define it here as well: The previous work done by Tulamandi et al., developed edible films based on papaya and added gelatin and soy protein. However, in this work, our films are based on gelatin and we have added papaya and soy protein. Additionally, our focus was to promote the large scale production of edible films, hence we selected blade coating method. We hope this explanation is sufficient for the readers.

 

1. When detailing the experimental method, it is more convenient and easy to follow if concentrations/ratios are used to express the composition of the samples, rather than grams. Please modify accordingly in text and Table 1

 

Response: We are thankful for the reviewer for highlighting this point. In the revised manuscript we have changed the text as per reviewer’s comments.

 

 

1. Please add the number of determinations for each sample and the used statistical evaluation method in the FILM CHARACTERIZATION section.

Response: Number of experiments and statistical analysis has been added in the revised manuscript on the relevant parts.

 

1. The results are merely presented, not properly discussed. Please add possible explanations for the observed changes. Please give an extended discussion on the obtained results, and correlate your findings with previous literature studies and prospective applications.

 

Response: The authors feel sorry for this basic mistake. In the revised manuscript, we have tried to elaborate our discussions on obtained results to keep things simpler for the readers. For examples, we have completely re-written the section 3.6, we have defined the water contact angles in section 3.3, and added more detailed discussion in the section 3.5.

 

 

1. In all graphs and tables please specify the SD, mean value, the number of repetitions, statistical significance.

 

Response: Errors bars (Standard deviation) are added in the figures in the revised manuscript.

1. and correction of the English language is mandatory! 

Response; Most of the English related issues are resolved in the revised manuscript.

Minor comments:

Introduction:

1. “The quality of the food is the most important factor” … for what? Please continue.
2. Please correct/rephrase: “which is atoms regularly found” (IAC)
3. Reference 16 is actually Tulamandi et.al., not Sridat et al. (JA)

Response: All of these minor comments are addressed in the revised manuscript and corrrections are made as per the reviewer’s suggestions.

Results:

1. Figure 2 title, please correct “Ebdible films”, “(indiacte with black nd red” and add/remove spaces between words. (JA)
2. The information from table 2 is redundant. (JA)
3. Figure 4 is referenced in the text before figure 3.
4. How were the values from Table 3 calculated? Please define “CA”.
5. In the CONTACT ANGLE section is stated that “Table 3 shows measurements of contact angles for various pure liquids in film samples” but Table 3 from the manuscript refers to “Optical and Barrier Properties of edible films”. Please correct.

Response: All of these minor comments are addressed in the revised manuscript and corrections are made as per the reviewer’s suggestions.

Reviewer 3 Report

 

1. There are different types of gelatin. The authors should add more details about what kind of gelatin they used in this study.
2. 'Error! Reference source not found.' appears many times in the ms.
3. Figure 5, the unit of contact angle should be added.
4. Figure 7, the quality of this figure should be improved to a higher level.
5. ‘These types of biopolymers help to make edible and degradable films [22].' More recent studies (doi.org/10.1016/j.actbio.2020.11.037; doi.org/10.1021/acs.langmuir.1c00550) should be included to support such claim.

Author Response

Reviewer No. 3

1. There are different types of gelatin. The authors should add more details about what kind of gelatin they used in this study.

Response: Few of the types of the gelatin are discussed in the revised manuscript and the type used in this work is also mentioned now.

 

2. 'Error! Reference source not found.' appears many times in the ms.

Response: this problem has been corrected in the revised manuscript.

3. Figure 5, the unit of contact angle should be added.

Response; The unit of contact angle has been added in the figure 5.

4. Figure 7, the quality of this figure should be improved to a higher level.

The authors are confused regarding the quality enhancement of Figure 7.. We are sorry but we exactly did not get the point, as in what sense the quality should be enhance in Figure 7.. However, the authors have enhanced the quality of the Figure 8.

5. ‘These types of biopolymers help to make edible and degradable films [22].' More recent studies (doi.org/10.1016/j.actbio.2020.11.037; doi.org/10.1021/acs.langmuir.1c00550) should be included to support such claim.

Response; These studies are cited in the revised manuscript.

Reviewer 4 Report

The manuscript "Gelatin and papaya based biodegradable and edible packaging films to counter plastic waste generation" is interesting and suitable for publication in terms of its central theme, the theme of solid waste generation is an important topic to be addressed in the area of ​​materials, this work may be published after minor corrections:

a) The citation pattern should be revised, for example, where we have "polymers, and its hydrophilicity [13] inherent [15]." it should be indicated [13,15].
b) In the introduction some more current researches and an introduction on solid agro-industrial waste should be inserted, consider the following papers: 10.1016/j.clema.2021.100040; 10.22034/GJESM.2022.02.10; 10.1016/j.cscm.2021.e00839.
c) The general formatting of the paper must be revised, see the publication rules, such as subtitle size, line numbering, subtitles, °C symbol in item 2.2, and various other errors throughout the paper;
d) Some subtopics of the methodology are short, think about merging them!!!
e) Review some units, try to work with MPa;
f) The statistical methodology must be revised and better explained by the authors;
g) The conclusion is not adequate, please rewrite and make it clearer to readers.

Author Response

Reviewer No. 4

The manuscript "Gelatin and papaya based biodegradable and edible packaging films to counter plastic waste generation" is interesting and suitable for publication in terms of its central theme, the theme of solid waste generation is an important topic to be addressed in the area of ​​materials, this work may be published after minor corrections:

a) The citation pattern should be revised, for example, where we have "polymers, and its hydrophilicity [13] inherent [15]." it should be indicated [13,15].

Response: The citation pattern has been corrected in the revised manuscript.

b) In the introduction some more current researches and an introduction on solid agro-industrial waste should be inserted, consider the following papers: 10.1016/j.clema.2021.100040; 10.22034/GJESM.2022.02.10; 10.1016/j.cscm.2021.e00839.

Response: these studies along with some more recent works are cited in the revised manuscript. We are thankful for the reviewers for mentioning these useful studies.

c) The general formatting of the paper must be revised, see the publication rules, such as subtitle size, line numbering, subtitles, °C symbol in item 2.2, and various other errors throughout the paper;

Response: General formatting rules have been followed in the revised manuscript along with corrections as mentioned by the respected reviewer.

d) Some subtopics of the methodology are short, think about merging them!!!

Response: We are very much thankful to reviewers for their valuable suggestions, we have now merged section 2.3.4 and 2.3.5 sections (as per original version).

e) Review some units, try to work with MPa;

Response; We have now converted most of the values in MPs.

f) The statistical methodology must be revised and better explained by the authors;

Response: Statistical methodology has been defined in the revised manuscript and explained in the relevant sections.

g) The conclusion is not adequate, please rewrite and make it clearer to readers.

The conclusion section has been fully re-written to make things easier for the readers.

Round 2

Reviewer 1 Report

The authors applied the necessary corrections.

Reviewer 2 Report

The authors managed to improve the quality of the manuscript and can be published after proofreading.