Functionality and Applicability of Starch-Based Films: An Eco-Friendly Approach
, Sukhvinder Singh Purewal 2, Monica Trif 3,†, Sajid Maqsood 4, Manoj Kumar 5, Vishal Manjunatha 1 and Alexandru Vasile Rusu 6,*,†Round 1
Reviewer 1 Report
Manuscript 1289960
Journal Foods
Title Functionality and applicability of starch-based films: An eco-friendly approach
The review entitled “Functionality and applicability of starch-based films: An eco-friendly approach” describes the use of starch-based films in food packaging, focusing on methods of preparation, improved properties and applications of starch bio-composites. The review is interesting and well structured. However, several aspects hamper the acceptance in its present form. Please follow the comments in the file.
Comments for author File: 
Comments.pdf
Author Response
We are extremely thankful to the esteemed reviewer for their valuable comments on the manuscript and to the Editor for giving us an opportunity to improve the manuscript. As desired, we have now revised the manuscript as per the comment of editor and reviewers. The revised version has been highlighted in red to make things clearer. Please find below point wise response to the reviewer’s comments:
The review entitled “Functionality and applicability of starch-based films: An eco-friendly approach” describes the use of starch-based films in food packaging, focusing on methods of preparation, improved properties and applications of starch bio-composites. The review is interesting and well structured. However, several aspects hamper the acceptance in its present form. Please follow the comments
Response: Authors are thankful to the reviewer for the inspiring comments.
Comment: L51-64 Please better describe the properties of starch for food applications. Which are the sources of starch? Which are the physicochemical properties of starch? How many types of starch are used for food packaging?
Response: As per valuable suggestions of esteemed editor Introduction section has been modified. Thank you.
L73-97 Please add some examples of the application of solvent casting for the preparation of starch-based films in food packaging (active and intelligent packaging).
Response: Section has been enriched with the information. Thank you.
L123-127 Please add other examples of the application of extrusion for the preparation of starch-based films in food packaging (active and intelligent packaging). Thermoplastic starch films (TPS-films) are often prepared with extrusion process. Please add this information
Response: Section has been enriched with the information. Thank you.
L165-171 Please better describe starch modifications for improved water vapor barrier properties. Are there other strategies to improve water vapor barrier properties in starch-based films? Please enrich this section and add other examples.
Response: Water vapour permeability section has been elaborated. Thank you.
L190-194 Rewrite this part. It is confusing and not clear. Revise the English
Response: Thank you for your observation. The sentence is now modified.
L228-231 Which is the best amylose:amylopectin ratio for proper mechanical properties? Please add this information in the text.
Response: Needful done. Thank you.
L243-251 Please add the molecular description of the interactions among starch and nanoclays. How nanoclay addition does improve the mechanical behaviour of starch films? Please be more specific in your analysis.
Response: Needful done. Thank you.
Table 1, 2, 3 Please divide the tables in “Barrier properties (WVP and oxygen permeability)” and “Mechanical properties”. Two tables are suggested (instead of three).
Response: Tables have been revised. Thank you.
L260-306 Please add some examples of UV-light protection of starch-based films in the food sector.
Response: Information has been enriched with examples of UV-light protection of starch-based films in the food sector.
L312-338 Please add a discussion on the compostability of starch-based films. Biodegradability is different from compostability. Please highlight the difference and add some applications of starch-based films in composting.
Response: Needful done. Thank you.
Comment: L349-354 Please consider that this application refers to intelligent packaging systems. Please divide the section 4 in two subsections: “4.1 Applications as active packaging”, and “4.2 Applications as intelligent packaging”. Re-organize this section on the basis of this suggestion.
Response: As per suggestion, section 4 has been divided into 4.1 Active packaging and 4.2 Intelligent packaging. Thank you.
Comment: L352-354 Please rewrite this sentence. It is confusing.
Response: Thank you for your observation. The sentence is now modified.
Comment: L372-373 Please rewrite this sentence. It is not correct in English
Response: Thank you for your observation. The sentence is now modified.
Comment: L384 Replace from reducing with to reduce
Response: Thank you for your observation. The sentence is now modified.
Comment: L387-390 Please rewrite this sentence. It is not correct in English
Response: Thank you for your observation. The sentence is now modified.
Comment: L411-412 Please add the subsection “4.2 Applications as intelligent packaging”. Please expand this subsection with some examples using TPS/clay/natural extract with pH-sensing properties. The paper doi.org/10.1016/j.fpsl.2021.100676 can help you in your general analysis. Please use it to summarize the main findings on the use of TPS/clay/natural extract as intelligent packaging systems.
Response: The section has been expanded and enriched with more information. Thank you.
Comment: L403-411 The suggested paper is also useful to expand the part focused on antioxidant films based on starch-clay composites. Please enrich the part on the antioxidant properties of starch-clay bio-composite films.
Response: The section has been enriched with more information. Thank you.
Comment: Please add a conclusion section describing the main results of the review and future directions for the research in this field.
Response: As per suggestion, the conclusion and future directions have been added.
Comment: L427-652 Revise the reference numbering on the basis of the reviewer’s suggestions. Revise the numbering also in the text. Please pay attention to the numbering in the text and in the reference list. Thanks
Response: Needful done. Thank you.
Reviewer 2 Report
The manuscript has to be revised by a native English speaker since several style, grammar and spelling mistakes were detected through the text.
The review is quite complete, resume some physical, biodegradability properties and applications of starch based edible films. However, did not have a real novelty, there are others reviews with the same information. The authors should comment, in order to enrich the manuscript, if some properties could be affected due to the contact with different kinds of food products regarding high to a low water activity of foods. There are articles related to the swelling behavior of films in high relative humidity environments and the release of active components.
Some other aspects to must be attended:
line 59: What did you mean with "gel el conversion (biopolymer) ..? The authors must add some examples in the same way for b) thin edible films.
lines 109-110: The sentence is not clear... what do mean with the torque values of films?
line 137: Do you want to say modified starch as a hydrophobic compound??
Please, revised the WVP values and the units in text and Table 1. Starch films use to have permeabilities around 10-10 or 10-11 g/m s Pa). The authors must unify the WVP and OP units in order to compare among reported results. Why is there a specific table for WVP (Table 1) and such results appeared again in table 3? When a WVP value is reported, it must be along with the relative humidity gradient and temperature, since edible films are environmental conditions dependent. Please, add the lacking data.
lines 292-293: revise the meaning of the sentence.
4. Applications
Starch based films are hydrophilic materials, many of the examples exposed did not conclude about film's properties after contact with foods. The authors should comment if some properties could be affected during storage and how to solve such drawbacks.
In addition, authors must incorporate some conclusions and future trends expected for starch based packaging.
Author Response
We are extremely thankful to the esteemed reviewer for their valuable comments on the manuscript and to the Editor for giving us an opportunity to improve the manuscript. As desired, we have now revised the manuscript as per the comment of the reviewer. The revised version has been highlighted in red to make things clearer. Please find below point-wise response to the reviewer’s comments:
Comment: line 59: What did you mean with "gel conversion (biopolymer) ..? The authors must add some examples in the same way for b) thin edible films.
Response: Thanks for the observation. Needful done.
Comment: lines 109-110: The sentence is not clear... what do mean with the torque values of films?
Response: As per suggestion, the sentence has been modified and explained well. Thank you.
Comment: line 137: Do you want to say modified starch as a hydrophobic compound??
Response: Sentence has been revised. Thank you.
Comment: Please, revised the WVP values and the units in text and Table 1. Starch films use to have permeabilities around 10-10 or 10-11 g/m s Pa). The authors must unify the WVP and OP units in order to compare among reported results. Why is there a specific table for WVP (Table 1) and such results appeared again in table 3? When a WVP value is reported, it must be along with the relative humidity gradient and temperature since edible films are environmental conditions dependent. Please, add the lacking data.
Response: Thank you for the observation. To avoid repetition of data, Table 1 and 2 has been merged and WVP removed from the table 3. Information of relative humidity and temperature has been added. Further, the authors tried to make the changes in the units but were not confident about the conversion factor.
Comment: lines 292-293: revise the meaning of the sentence.
Response: The sentence has been revised. Thank you.
Comment: 4. Applications
Starch based films are hydrophilic materials, many of the examples exposed did not conclude about film's properties after contact with foods. The authors should comment if some properties could be affected during storage and how to solve such drawbacks. In addition, authors must incorporate some conclusions and future trends expected for starch-based packaging.
Response: As per suggestion, the application section has been modified and elaborated. Also, the conclusion part has been added. Thank you.
Round 2
Reviewer 1 Report
Manuscript: foods-1289960
Journal Foods
Title “Functionality and applicability of starch-based films: An eco-friendly approach”
Authors revised the original manuscript according to comments of Reviewer’s. The manuscript has been improved in comparison to original submission. However, several comments were partially addressed. The review needs a better discussion of several aspects throughout the manuscript. For this reason, a further major revision is suggested.
Please follow the comments in the file.
Comments for author File: Comments.pdf
Author Response
Dear Reviewers,
We, the co-authors, would like to let to thanks to for the comments and suggestions. As authors, we may not agree with a comment—this is the essence of the scientific debate, a natural part of the business. We implemented the text and answered to your queries. Hope you will agree with all our modifications/implementations.
Reviewer 1:
The manuscript was improved in English style and content. However, revise the following aspects previous to publication:
Previous request: " The authors should comment, in order to enrich the manuscript, if some properties could be affected due to the contact with different kinds of food products regarding high to a low water activity of foods. There are articles related to the swelling behavior of films in high relative humidity environments and the release of active components" has not been attended yet, please cite some bibliography related with this topic (See this article for general aspects: https://doi.org/10.1016/j.jfoodeng.2006.12.010 ).
We thank you the reviewer for suggestions. The reviewer suggestion to improve the manuscript by considering the mentioned properties is appreciated, but if we focus on such properties, the manuscript will become a „real occtopus“ and not anymore a focused manuscript, and such topic is of great importance and could be the base for another review. We will consider such a review in the next future. Thank you again fort he productive suggestions.
Line: 23: change alternate by alterntive...
Done. Thank you.
Line 72: change b) thin edible films by b) thin edible films from gel.
Done. Thank you.
Lines 72-75: I do not agree with the introduction of ceramic-based materials at this point. Please, center the explanation to the gelation of biopolymers.
The section has been improved, valuable references added. Thank you.
Lines 146 - 147: Please, change the sentence as follows: As screw speed is increased, the torque value of the extrusion process to obtain films, is decreased.
Since, according to reference, torque is a parameter that describes the extrusion process but it is not a property of films. Therefore, the phrase "torque of films" has no sense.
Done. Reference extra added. Thank you.
Reviewer 2 Report
The manuscript was improved in English style and content. However, revise the following aspects previous to publication:
Previous request: " The authors should comment, in order to enrich the manuscript, if some properties could be affected due to the contact with different kinds of food products regarding high to a low water activity of foods. There are articles related to the swelling behavior of films in high relative humidity environments and the release of active components" has not been attended yet, please cite some bibliography related with this topic (See this article for general aspects: https://doi.org/10.1016/j.jfoodeng.2006.12.010 ).
Line: 23: change alternate by alterntive...
Line 72: change b) thin edible films by b) thin edible films from gel.
Lines 72-75: I do not agree with the introduction of ceramic based materials at this point. Please, center the explanation to gelation of biopolymers.
Lines 146 - 147: Please, change the sentence as follows: As screw speed is increased, the torque value of the extrusion process to obtain films, is decreased.
Since, according to reference, torque is a parameter that describes the extrusion process but it is not a property of films. Therefore, the phrase "torque of films" has no sense.
Author Response
We, the co-authors, would like to let to thanks to for the comments and suggestions. As authors, we may not agree with a comment—this is the essence of the scientific debate, a natural part of the business. We implemented the text and answered to your queries. Hope you will agree with all our modifications/implementations.
Reviewer 2:
Authors revised the original manuscript according to comments of Reviewer’s. The manuscript has been improved in comparison to original submission. However, several comments were partially addressed. The review needs a better discussion of several aspects throughout the manuscript. For this reason, a further major revision is suggested.
Please follow the comments:
Abstract
The abstract should be rewritten. In particular L18-L22 could be shortened. The main findings and the main applications of starch-based films (active and intelligent packaging) in the food sector should be summarized. Moreover, the main procedures to prepare these films and the film modifications to enhance film properties should be mentioned. Please revise the abstract
The abstract has been rewritten. Thank you
L57-63 Revise this part. Authors should refer to the application of starch in the packaging material. In addition, the main procedures to modify starch (esterification, cross-linking, and oxidation) should be presented (L61) with the effect of these procedures on film properties. Please revise
We improved this part. Thank you.
L122-124 Revise this sentence. It is not correct in English. In particular, at L123-124 prolonged the packaged products? Probably extended the shelf-life of packed product!! Revise
Done. Thank you.
L122-134 The reviewer’s request was: “Please add some examples of the application of solvent casting for the preparation of starch-based films in food packaging (active and intelligent packaging).” Although some examples of active packaging application of starch-based films produced with the solvent casting method are reported, no examples of intelligent packaging application are discussed and included in this sub-section. Please add some examples. Thanks
Some examples have been added. Thank you.
L151 Please briefly describe the meaning of “torque value”. It helps readers. Thanks
L169-177 This part could be enriched with other examples of starch films modified with the inclusion of nanoclays and prepared with the extrusion process as active and intelligent packaging.
Some examples have been added. Thank you.
L177-178 A new section need to be included. Before the description of properties of starch-based films, a section describing the main methods for the modification of starch-based film is strongly suggested. These procedures include the addition of metal oxide nanoparticles (doi.org/10.1111/1541-4337.12727), the addition of nanoclays (doi.org/10.1016/j.fpsl.2021.100676), the blending with other biopolymers (doi.org/10.3390/polym13091396), the addition of cellulose nanocrystals (doi.org/10.1016/j.ijbiomac.2021.07.017). The suggested reviews should be all included in the new section as they are a good critical snapshot of the properties of starch films reinforced with nanoparticles, nanoclays, cellulose nanocrystals and blending with other biopolymers. Please describe in details the film properties improved after the addition of these fillers/biopolymers. Thanks
Authors thank the reviewer for valuable suggestion. As already the manuscript has been improved in several sections including some examples suggested by reviewer to be included in the a new section. We consider adding a new section will dublicate some of the information. Such a section could be a whole review paper. We hope the reviewer will agree with our decision.
L223-230 Please add other examples of starch modification affecting WVP. I could suggest esterification or cross-linking. Which is the effect of these procedures on WVP of starch-based films? Please discuss and enrich this part
Some examples have been added. Thank you.
L227 Replace “Further, Zamudio‐Flores et al. [37] (2007)” with “Further, Zamudio‐Flores et al. (2007) [XX]”
Done. Thank you.
L230-232 Delete. It is not important in this section
Done. Thank you.
L255-257 Please rewrite this part. It is confusing. Several starch-based films are modified with the addition of essential oils or essential oil compounds (thymol, carvacrol and so on). Which is the effect of essential oil addition on oxygen permeability? Please discuss this aspect in this section with relevant references. Thanks
Improved. Thank you.
L256-257 What do you mean with “rise of oxygen solubility in the oil”? Which oil? Please be clear in the writing and your statements.
Done. Thank you.
L294-296 Is this ratio affected by the starch type? Please discuss this aspect in the text
Improved. Thank you.
L317-324 The reviewer’s request was: “Please add the molecular description of the interactions among starch and nanoclays. How nanoclay addition does improve the mechanical behaviour of starch films? Please be more specific in your analysis.” Authors discussed the work of Wu et al. (2009) “Investigation into the performance and mechanism of SiO2 nanoparticles and starch composite films.”
The discussion of this work is ok but the reviewer’s request was the discussion of the mechanical properties of starch-based films added with nanoclays (e.g., halloysite nanotubes, montmorillonite, layered double hydroxides and so on). Please add some papers dealing with this aspect at L317-324.
Improved and references added. Thank you.
L380-386 Delete this part. It is out of the scope of the review.
Done. Thank you.
L380-392 Please add some examples of UV-light barrier properties of starch-based films modified with nanoclays, fibers, cellulose nanocrystals, or blended with other biopolymers. There are several examples in literature. Please include these examples in this section. Thanks
Some examples added. Thank you.
L430 Which nanoclays were used by Ojogbo et al.? Please be more specific. Revise
Done. Thank you.
L450 oil? Again, which oil? Revise and be more specific
Done. Thank you
L466-473 Totally rewrite this part. Several sentences are confusing or not complete. Please be clear and concise. Please use short sentences
Done. Thank you.
L488 Please replace effects with growth.
Done. Thank you.
L516 Please explain the meaning of TBHQ. Tertiary butylhydroquinone should be mentioned. Thanks
Done. Thank you.
L520 Delete “while also reducing the generation of olive by-products.”
Done. Thank you.
L522 Delete “and antimicrobial effect against E. coli and S. aureus of these novel active films”
Done. Thank you.
L518-522 Please better discuss the paper of Garcia et al. Which is the antioxidant effect of this novel active film? Garcia et al. reported: “The scavenging capacities of starch-based films incorporated with OE significantly increased (p < 0.05) with the OE concentration. Thus, as OE content increased higher DPPH, ABTS and FRAP values were obtained, which may be linked with the antioxidant activity of the extract and the presence of bioactive compounds in the edible films, such as phenolic acids, from OE.” Please re-elaborate this part that need to be included at L518-522. Please do not copy in order to avoid plagiarism
Done. Thnak you.
L529-541 The 4.2 Section is short in comparison to 4.1 Section. In my opinion, the intelligent packaging applications are not less important than active packaging applications. Do you agree?
For this reason, the 4.2 section needs revision and better discussion. Some examples of pH sensing properties of starch films added with metal oxide nanoparticles could be discussed (e.g., doi.org/10.1016/j.ijbiomac.2019.06.018; DOI: 10.1039/D0RA05986B). In addition, other intelligent properties of starch-based films could be introduced and discussed (e.g., humidity sensors doi.org/10.1166/jbns.2018.1518). Moreover, if no applications of starch-based films as oxygen sensing material are available this topic could be suggested for future investigations. Revise this part following the reviewer’s suggestions.
The section 4.2 intelligent packaging has been improved. Thank you.
L595-868 Revise the reference numbering on the basis of the reviewer’s suggestions. Revise the numbering also in the text. Please pay attention to the numbering in the text and in the reference list. Thanks
Done. Thank you.
This reviewer congratulates with all authors for the work done and the improvement of the manuscript. Following all the suggestions this review will be accepted and published in “Foods”. Congratulation
We thank the reviewer for the time and advices/suggestions to improve the manuscript. We hope the revised version will be accepted and published.
Author Response File: 
Author Response.docx
