A New Approach for the Utilization of Technical Egg Albumen Based on Acid–Thermal Coagulation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

The article " A new approach for the utilization of technical egg albumen based on acid-thermal coagulation" provides valuable data on the physicochemical and microbiological characteristics of TA and its potential as animal feed.

Here are my observations:

The introduction gives a broad background on egg processing waste and its regulatory context in the European Union. The introduction is heavily focused on general background information and could better articulate the specific research gap addressed by this study. Some statements lack proper citation (e.g., about the benefits of using TA as animal feed).

The Materials and Methods section offers a detailed explanation of the methods used for TA characterization, including proximate composition and amino acid profiling. Some experimental setups (e.g., the choice of citric and phosphoric acids) lack justification based on prior research or theoretical rationale. More detail on the statistical analysis (e.g., why one-way or two-way ANOVA was chosen) would improve transparency.

The result section is well-structured and presents the results, with clear use of figures and tables for proximate composition, amino acid profiling, and microbiological status. Statistical analysis is adequately applied to assess differences between treatments. Some figures are cluttered and could be simplified for better readability.

The Discussion section links the findings to the broader context of the circular economy and sustainable waste management and also highlights the potential industrial applicability of the method. The discussion tends to repeat results rather than offering a critical interpretation or comparison with similar studies. The authors do not address potential limitations of the acid-thermal coagulation method or explore alternative processing techniques. The novelty and broader implications of the study are not emphasized enough.

 

 

Author Response

We sincerely appreciate the reviewer's thoughtful comment and insight. Below are presented all of the comments and our replies.

Comment 1: The introduction gives a broad background on egg processing waste and its regulatory context in the European Union. The introduction is heavily focused on general background information and could better articulate the specific research gap addressed by this study. Some statements lack proper citation (e.g., about the benefits of using TA as animal feed).

Response 1: Thank yоu for pointing this out. We agree with this comment. Unfortunately, there is little information on using liquid egg waste products for feed. The sources we found are mentioned in line 63.

Comment 2: The Materials and Methods section offers a detailed explanation of the methods used for TA characterization, including proximate composition and amino acid profiling. Some experimental setups (e.g., the choice of citric and phosphoric acids) lack justification based on prior research or theoretical rationale. More detail on the statistical analysis (e.g., why one-way or two-way ANOVA was chosen) would improve transparency.

Response 2: Thank yоu for pointing this out. We agree and accordingly, add the following information to the text: "In our preliminary study, we used four different types of acids. From them the most suitable acids for pH correction are citric acid (CA) and phosphoric acid (PA) showed the best values ​​of the production indicators yield and pressing efficiency". 
Meanwhile the last sub-section of Material and Methods explains the used ANOVA methodologies - "One-way ANOVA was used to determine whether the variability of the results was due to chance or to the factor in the analysis – significant variation between both batches technical albumen. Two-way ANOVA was used to determine the significance of the factors influencing the parameters of the dried egg products from technical albumen - type of acid used and time of storage"

Comment 3: The result section is well-structured and presents the results, with clear use of figures and tables for proximate composition, amino acid profiling, and microbiological status. Statistical analysis is adequately applied to assess differences between treatments. Some figures are cluttered and could be simplified for better readability.

Response 3: Thank yоu for pointing this out. We agree that some of the figures are cluttered, but we provide more data so that the results can be compared.

Comment 4: The Discussion section links the findings to the broader context of the circular economy and sustainable waste management and also highlights the potential industrial applicability of the method. The discussion tends to repeat results rather than offering a critical interpretation or comparison with similar studies. The authors do not address potential limitations of the acid-thermal coagulation method or explore alternative processing techniques. The novelty and broader implications of the study are not emphasized enough.

Response 4: Thank yоu for pointing this out. We agree and add information about the new aspects of the method in the abstract and conclusion section:

Abstract: Proteins have the property at the isoelectric point of weakening their repulsive forces. This property is the basis of a TA recovery method using pretreatment to reduce moisture before drying.

Conclusion: It is necessary to carry out additional analyzes during storage in order to determine the possible shelf life of the feed raw material. Coagulation of the product causes a phase transition of the product from liquid to solid. This allows the use of more versatile, simpler and cheaper equipment for drying as compared to spray dryers. The method involves pre-dehydration of the material before drying, which can reduce energy consumption and the negative effect of heat on the product. Industrial tests should show the economic efficiency of this the method and whether it will be used by egg processors. Larger scale tests should show the energy consumed for coagulation and drying of the product.

Reviewer 2 Report

Comments and Suggestions for Authors

 

 

*Review

Line 17: “The highest yield was obtained when using citric acid 97.79%.” sounds confusing, kindly revise for clarity

Line 18: change “technical albumen” to TA for consistency

The word “we” is quite repeated kindly minimise or delete it in lines 11, 13, 14

Line 22: what is ABPs

Lines 20-22: “Microbiological contamination has decreased potential due to decrease of water activity to the extent that it meets the requirements of European legislation for the processing of ABPs and use as feed.” Kindly rewrite for clarity.

Abstract: The abstract sections lack the presentation of the study aim coupled with justifications for carrying out the research. It is highly recommended for revision to make the section coherent and scientific.

Line 10-11: “Technical albumen (TA) is a liquid waste from egg processing enterprises and occupies a 10 share of 10-15% of the waste.” Line 16: “Initially, TA is significantly microbiologically 16 contaminated.” and lines 56-57 “Technical albumen (TA) is a viable animal feed due to its excellent amino acid profile, energy content and presence of antimicrobial proteins”. These two sections present different definitions of “Technical albumen (TA)” in different context. Kindly check and revise for coherency.

line 69: correct “technical albumen” to TA since it has been introduced in line 56: “Technical albumen (TA)”. Hence subsequent sections must follow suit.

Line 65: the statement is vague. Authors should identify the key reason why citric acid (CA) and phosphoric acid (PA) are the most suitable acids for pH correction. Also, line 63 what makes the spray drying technology high investment costs as its major disadvantage. Kindly give details to make the study scientific.

Lines 66-67: “In this study, we characterized the technical albumen to evaluate the most suitable processing and production of dried egg products from it”. Can authors state the exact processing and production means of drying egg products proposed to utilize in the study at this section before the subsequent section of materials and methods.

Line 77: change “is” to “was”. Kindly report in past or if otherwise consider the appropriate tenses and use it entirely.

Line 80: “The technical protein was processed according to the method of Saraliev et al. [20] with modifications.” This statement should be cut and paste at the methodology section under a sub-heading “technical protein extraction”

In general the material section of the paper should focus on outlining the exact materials utilized in the study coupled with its various sources of out sourcing it to make the work more scientific.

Was the TA outsourced from a production plant or it was produced from a sourced chemical.

A clear view of TA as albumin liquid secure from egg treatment in the various processing houses and TA concept as an industrial byproduct source utilized as an animal feed is confusing. Kindly revise the entire manuscript to avoid discrepancies. Was the TA lyophilised to get an egg product? Because 165: Initially 5 g of dried egg product from technical albumen”. To an extent a schematic diagram should be added for understanding.

Sections 2.2. Methods: kindly number the various sub-sections embedded in bulleting’s such as “Proximate composition”, “Protein separation and identification”, “Amino acid profiling” and other sections where possible accordingly in the work entirely. Also, some sub-sections are italicised e.g. Iine 122: “pH determination”, line 127: “Color characteristic determination” kindly check and fix entirely where necessary.

Line 98: correct “As a protein marker was used the Precision Plus Protein Standards” as “As a protein marker was used as the Precision Plus Protein Standards”

Line 106: “derivatives of was carried out” complete the statement. Derivatives of what…… or delete the “of”

Line 123: correct “It is measured”

Line 128: correct “The color is determined”. Also, give details of viewing angle and other relevant information’s for executing the color test.

Line 140: correct “sample is homogenized”

Line 145: correct “status is represented”

Tables 2, 3, 6 and 7: change digits with comma (6,90a±0,06) to 6.90a±0.06

In General: The whole concept of TA is not well established. Authors are recommended to reveal the main concept of TA and revise the objectives of the study to match the comprehensive results and discussion section of the paper for coherency.

 

 

 

 

Comments for author File: Comments.pdf

Author Response

We sincerely appreciate the reviewer's thoughtful comment and insight. Below are presented all of the comments and our replies.

Comment 1: Line 17: “The highest yield was obtained when using citric acid 97.79%.” sounds confusing, kindly revise for clarity

Response 1: Thank yоu for pointing this out. We agree with this comment. I change the text in line 19, and the sentence is: A better yield was obtained when using citric acid 97.79% instead of phosphoric acid.

Comment 2: Line 18: change “technical albumen” to TA for consistency.

Response 2: Thank yоu for pointing this out. We agree with this comment. I change the text in Abstract in this way in line 16 and 20.

Comment 3: Line 22: what is ABPs

Response 3: Thank yоu for pointing this out. We agree with this comment. I add animal by-products in line 24

Comment 4: Lines 20-22: “Microbiological contamination has decreased potential due to decrease of water activity to the extent that it meets the requirements of European legislation for the processing of ABPs and use as feed.” Kindly rewrite for clarity.

Response 4: Thank yоu for pointing this out. We agree with this comment and change the sentence line 22-25

Comment 5: Abstract: The abstract sections lack the presentation of the study aim coupled with justifications for carrying out the research. It is highly recommended for revision to make the section coherent and scientific.

Response 5: Thank yоu for pointing this out. We agree with this comment and added new sentences in the abstract line 11-13

Comment 6: Line 10-11: “Technical albumen (TA) is a liquid waste from egg processing enterprises and occupies a 10 share of 10-15% of the waste.” Line 16: “Initially, TA is significantly microbiologically 16 contaminated.” and lines 56-57 “Technical albumen (TA) is a viable animal feed due to its excellent amino acid profile, energy content and presence of antimicrobial proteins”. These two sections present different definitions of “Technical albumen (TA)” in different context. Kindly check and revise for coherency.

Response 6: Thank yоu for pointing this out. We agree with this comment. TA is a waste product and is significantly microbiologically contaminated and therefore not intended for human consumption. However, this waste contains the mentioned substances, which, however, can only be used if the product undergoes appropriate treatment. We change the sentence in line 60.

Comment 7: Line 69: correct “technical albumen” to TA since it has been introduced in line 56: “Technical albumen (TA)”. Hence subsequent sections must follow suit.

Response 7: Thank yоu for pointing this out. We agree with this comment. I change the text in whole text in this way in line 77,83,223,233,392,425,445,446,451 and 520.

Comment 8: Line 65: the statement is vague. Authors should identify the key reason why citric acid (CA) and phosphoric acid (PA) are the most suitable acids for pH correction. Also, line 63 what makes the spray drying technology high investment costs as its major disadvantage. Kindly give details to make the study scientific.

Response 8: Thank yоu for pointing this out. We agree with this comment. I have added additional information from our previous studies, why we choose these acids in line 70-73. I also change the sentence on line 66-67 to make the source of information clear.

Comment 9: Lines 66-67: “In this study, we characterized the technical albumen to evaluate the most suitable processing and production of dried egg products from it”. Can authors state the exact processing and production means of drying egg products proposed to utilize in the study at this section before the subsequent section of materials and methods.

Response 9: Thank yоu for pointing this out. We agree with this comment. I add additional information about the principle of the method in lines 74-76. Readers can find the scheme of the method in our previous open access study which we cite as number [20].

Comment 10: Line 77: change “is” to “was”. Kindly report in past or if otherwise consider the appropriate tenses and use it entirely.

Response 10:  Thank yоu for pointing this out. We agree with this comment. I made the change in line 87

Comment 11: Line 80: “The technical protein was processed according to the method of Saraliev et al. [20] with modifications.” This statement should be cut and paste at the methodology section under a sub-heading “technical protein extraction”

Response 11 : Thank yоu for pointing this out. We agree with this comment. I made the desired change in line 98-103

Comment 12: Was the TA outsourced from a production plant or it was produced from a sourced chemical.

Response 12: Thank yоu for pointing this out. We agree with this comment. I add sentences in line 84-85 from which it is understood that the TA originates from a production plant.

Comment 13: A clear view of TA as albumin liquid secure from egg treatment in the various processing houses and TA concept as an industrial byproduct source utilized as an animal feed is confusing. Kindly revise the entire manuscript to avoid discrepancies. Was the TA lyophilised to get an egg product? Because 165: Initially 5 g of dried egg product from technical albumen”. To an extent a schematic diagram should be added for understanding.

Response 13: Thank yоu for pointing this out. We agree with this comment. From Line 98 we provide a much clearer description of the processing and how and why. “2.2.1.1.            TA extraction

The  TA was processed according to the method of Saraliev et al. [20] with modi-fications. Citric and phosphoric acid were used for pH correction. Part of the acidified samples were additionally treated with n-hexane to extract the fats. Separation of fats from the samples treated with n-hexane and treated with citric acid (CADF) and phosphoric acid (PADF) is carried out in function before the coagulation process. The obtained coagulates are pressed to evaluated the pressing efficacy followed by drying in a hot rack oven at 80 ℃ for 6 hours according to COMMISSION REGULATION (EU) No 142/2011 [21].”

Comment 14: Sections 2.2. Methods: kindly number the various sub-sections embedded in bulleting’s such as “Proximate composition”, “Protein separation and identification”, “Amino acid profiling” and other sections where possible accordingly in the work entirely. Also, some sub-sections are italicised e.g. Iine 122: “pH determination”, line 127: “Color characteristic determination” kindly check and fix entirely where necessary.

Response 14: Thank yоu for pointing this out. We agree with this comment. I numbered the subsections in line 98,104,111,118,139,144,148,155,167,172,179,189.

Comment 15: Line 98: correct “As a protein marker was used the Precision Plus Protein Standards” as “As a protein marker was used as the Precision Plus Protein Standards”

Response 15: Thank yоu for pointing this out. We agree with this comment. The change was made in line 116.

Comment 16: Line 106: “derivatives of was carried out” complete the statement. Derivatives of what…… or delete the “of”

Response 16:  Thank yоu for pointing this out. We agree with this comment. The change was made in line 123.

Comment 17: Line 123: correct “It is measured”

Response 17:  Thank yоu for pointing this out. We agree with this comment. The change was made in line 140.

Comment 18: Line 128: correct “The color is determined”. Also, give details of viewing angle and other relevant information’s for executing the color test.

Response 18:  Thank yоu for pointing this out. We agree with this comment. The information is added in the methodology for color determination.

Comment 19: Line 140: correct “sample is homogenized”

Response 19:  Thank yоu for pointing this out. We agree with this comment. The change was made in line 157.

Comment 20: Line 145: correct “status is represented”

Response 20:  Thank yоu for pointing this out. We agree with this comment. The change was made in line 162.

Comment 21: Tables 2, 3, 6 and 7: change digits with comma (6,90a±0,06) to 6.90a±0.06

Response 21:  Thank yоu for pointing this out. We agree with this comment. I changed tables 2, 3, 6 and 7 according to the model shown.

 

Reviewer 3 Report

Comments and Suggestions for Authors

In this study, the authors introduced a novel Technical Albumen (TA) processing method, employing thermal-acid coagulation with citric and phosphoric acids as an alternative to spray drying. Through the analysis of physicochemical and microbiological parameters, they detailed the raw TA and the resulting finished product. The issues that require further clarification and modification are as follows:

1. Line 56: The authors did not provide a sufficient introduction to the significance of "Technical Albumen (TA)" as the subject of the study. This may lead to confusion for the readers.
2. Last paragraph of the Introduction: The significance and potential applications of this study are missing. It is recommended that the authors include this information.
3. Figure 1: The terms "batch 1 (TA1) & 2 (TA2)" are used, but the authors did not provide an explanation of what these batches represent. Please clarify this in the figure legend.
4. Table 2: The authors should verify whether the p-value in the last row of data is correct. For example, the two data points for Tryptophan (3.00 ^a ±0.21 and 4.55 ^a ±0.19) appear to differ significantly, yet the p-value is 0.935071, which seems contradictory. Please check and correct this.
5. Figure 3: What do the values 5.1, 5.0, and 4.9 on the y-axis represent? Are these pH values? Please clarify this in the figure legend.
6. Tables 5, 6, and 7: The values should be presented as "5.32 ^a,x ±0.01" instead of "5,32 ^a,x ±0,01". Please check and correct the formatting. Also, clarify what the "x" and "y" represent in these tables.
7. Figure 5: Is there a significant difference between the values of the same sample at 24 hours and 1 month? It is recommended that the authors indicate this difference in the figure.
8. Conclusions: The conclusion should summarize the entire study and include prospects for future work. It is suggested that the authors revise this section to include relevant data.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

We sincerely appreciate the reviewer's thoughtful comment and insight. Below are presented all of the comments and our replies.

Comment 1: Line 56: The authors did not provide a sufficient introduction to the significance of "Technical Albumen (TA)" as the subject of the study. This may lead to confusion for the readers.

Response 1: Thank yоu for pointing this out. We agree with this comment. The amount of TA as waste from egg processing is significant. I add the information that it is second in quantity among waste, in line 52.

Comment 2: Last paragraph of the Introduction: The significance and potential applications of this study are missing. It is recommended that the authors include this information.

Response 2: Thank yоu for pointing this out. We agree with this comment. I added information in lines 73-76 about the benefits of applying the method and research.

Comment 3: Figure 1: The terms "batch 1 (TA1) & 2 (TA2)" are used, but the authors did not provide an explanation of what these batches represent. Please clarify this in the figure legend.

Response 3: Thank yоu for pointing this out. We agree with this comment. In the Material section, we have added a detailed description of the origin of both batches. Lines 87-89

Comment 4 Table 2: The authors should verify whether the p-value in the last row of data is correct. For example, the two data points for Tryptophan (3.00 ^a ±0.21 and 4.55 ^a ±0.19) appear to differ significantly, yet the p-value is 0.935071, which seems contradictory. Please check and correct this

Response 4: Thank yоu for pointing this out. We agree with this comment. We double check it and we found a mistake. The correction is marked in the text.

“Tryptophan    3.00±0.21          3.55a±0.19       0.935071” The second value is 3.55 not 4.55.

Comment 5: Figure 3: What do the values 5.1, 5.0, and 4.9 on the y-axis represent? Are these pH values? Please clarify this in the figure legend.

Response 5: Thank yоu for pointing this out. We agree with this comment, and corrected the legend of Figure 3 Line  271.

Comment 6: Tables 5, 6, and 7: The values should be presented as "5.32 a,x ±0.01" instead of "5,32 a,x ±0,01". Please check and correct the formatting. Also, clarify what the "x" and "y" represent in these tables.

Response 6: Thank yоu for pointing this out. We agree with this comment. I corrected tables 2, 3, 5, 6, 7 according to the model shown. Also, added the missing information about "x" and "y".  “Results are presented as Means±SEM; superscripts a,b,c,d indicate significant (P ≤ 0.05) differences between the dried technical albumen products for each parameter separately, while. superscripts x,y indicate significant (P ≤ 0.05) differences between time periods.”

Comment 7: Figure 5: Is there a significant difference between the values of the same sample at 24 hours and 1 month? It is recommended that the authors indicate this difference in the figure.

Response 7: Thank yоu for pointing this out. We agree with this comment. Additional information is added into the figure.

Comment 8: Conclusions: The conclusion should summarize the entire study and include prospects for future work. It is suggested that the authors revise this section to include relevant data.

Response 8: Thank yоu for pointing this out. We agree with this comment. We have added additional information with a summary of the results and guidelines for future research. Lines 530-538.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The article has been improved and is ready for publication. 

Reviewer 2 Report

Comments and Suggestions for Authors

Thanks for considering the suggestions and revising the paper accordingly.

Kindly change the description beneath Figure 3: ph to pH

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have made the necessary changes, I recommend accept the manuscript.