Improving the Technological and Nutritive Properties of Gluten-Free Bread by Fresh Curd Cheese Enrichment
Round 1
Reviewer 1 Report
Detailed recommendation:
Key words: please add “gluten, enrichment” to the list
Abstract: please add some data to the abstract
To the Introduction, add more information about gluten, its role in the creation of dough, the qualities of gluten-free bread and the possibility of enriching such bread.
Materials: add more information about used flours (dry matter content, falling number etc.)
What was proportion of used components?
Methods: please better described methods of nutrition analysis
Could you in conclusions show what adding of cheese is the best?
In how many replicates were the determinations made?
Author Response
Response to reviewer comment´s 1
All changes along the manuscript were highlighted with a green tone.
Keywords:
The suggested words were included in the keywords.
Abstract:
Some data was included in the abstract section as suggested.
Introduction:
The addition of more information about gluten in terms of structure and bread quality was included in the introduction section, as suggested.
Materials:
The detailed flours chemical composition was removed from this manuscript as kindly asked by the Editors, due to the similarity found with other published papers of our research group. However, the sentence “Detailed chemical composition of the gluten-free flours used as described earlier by other authors [16]" was included in the raw materials section.
Components proportion:
Replacements were based on a gluten-free flours basis, substituting the dry extract of each curd cheese percentage on 100 g of flour [16]. This information was included in the Gluten-free bread dough´s preparation.
Nutritional methods description:
Standard methods were included. However, to avoid the overlapping with other papers already published, the authors were advised to resume the description of the methods. Two quoted reference was included to support the methods applied, in a detailed description of the methods is provided.
Conclusions:
The sentence: "Considerable improvements in terms of technological performance and nutritional profile of the gluten-free bread were achieved for higher levels of curd cheese tested (20 % w/w)", as suggested by the reviewer.
Replicates made:
In all the methods described, triplicates were applied and using 3 different bread.
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Considering all the suggestions proposed, we expect that the revised manuscript is clearer and organized, after following all fruitful suggestions and comments from the Reviewer 1.
Reviewer 2 Report
The paper “Improving the technological and nutritive properties of gluten-free bread by fresh curd cheese enrichment” aims to be a contribution to formulation of gluten-free bread, which is nowadays a challenge at a technological and nutritional level. The Authors include among the ingredients curd cheese at different percentages and study the influence thereof on the technological and nutritional profile of bread.
The paper is interesting, however it is not suitable for publication at the present state and requires extensive revision. The first aspect to address is the revision of the English language. Apart from spelling and grammar mistakes, several sentences require reformulation and editing.
Here below other hints for improvement:
INTRODUCTION
Over the last few years, several papers were published on the challenges of GF breadmaking and the use of alternative flours, among which legumes. I suggest including more recent authoritative papers in line 48-50.
MATERIALS AND METHODS
From line 94 the headings are wrong, they require revision, e.g. “2.1. Gluten-free bread dough’s preparation”, this is 2.2. please, amend all headings.
Table 1 requires attention or better explanation. You state ingredient amount is expressed in percentages, but the sum of ingredients for the various formulations is not 100%, e.g. 99.9 for CB, 101.1 for CcB5%, 101.7 for CcB10%, 102.8 for CcB15%, and 105.8 for CcB20%. Please, check and amend or explain. In addition, you state that extra ingredients account for 7.1%, but the sum of the mentioned (i.e. salt – 0.8 %; sucrose – 1.6 %; yeast – 1.6 %, XG - 0.3 % and vegetable fat– 3.1 %) is 7.4%.
RESULTS AND DISCUSSION
Line 186: you stated “no significant (p > 0.05) impact on water absorption (WA), dough development time (DDT) and dough stability (DST)” instead of dough stability did you mean DSF? Please, check.
Line 248: Figure 3. The letters referring to each figure are faded, please, amend the graphics.
Line 254: please, amend in CO2
Line 272-273: check English language
Line 285-286: please, make clearer what you mean when you state A- and B-
Line 304: my suggestion is to mention before CB because it is first in the figure and then CcB. In addition, please delete “without Cc incorporation” after CB, as it is known and not necessary to be specified.
Line 372-373: you state “One can suggest that the incorporation of Cc to GFB formulations can be an alternative to obtained breads with reduce glycemic response [32]”. Did you check/measure the glycaemic index of your breads? If so, please show results. If not, please, delete this conclusion. The relationship between carbohydrate content and glycaemic response must not be taken for granted
Line 347-377: did you perform the profile of fats of your bread? If not, your conclusion is not nutritionally acceptable, you need to know exactly how much is the content in saturated fats.
Line 381: please quote “Reg. (CE), Nº 1924/2006; Dir. No 90/494 (CE)” in an appropriate way.
Line 382: “suggesting the possibility to associate a nutritional claim to these breads” you cannot claim it in your breads. Please, delete this sentence.
Line 383-385: as recently stated in Melini & Melini “Gluten-Free Diet: Gaps and Needs for a Healthier Diet - Nutrients 2019, 11(1), 170; https://0-doi-org.brum.beds.ac.uk/10.3390/nu11010170”, one of the main key inadequacies of the GF diet is a high intake of fat, so in my opinion it is hard to accept the final consideration that “These nutritional improvements obtained by the addition of Cc on GFB formulation can give an additional contribution to fulfill the nutritional daily diet requirements of celiac patients and gluten-sensitive individuals”. However, you may put emphasis on the protein content of your experimental bread, as it assures a good content in proteins, when the abovementioned authors found that low protein intake is among the key inadequacies of currently available GF products.
What about salt content in your bread?
CONCLUSION
Line 392: GFB: it is not general, please specify you are referring to your experimental bread
Author Response
Response to reviewers’ comments 2.
All changes along the manuscript were highlighted with a yellow tone.
Introduction:
Lines 48-50, More recent quoted references were included, as suggested.
2.Materials and methods
Line 94 and in the whole manuscript, the headings were amended and corrected, as corrected by the reviewer.
3. Table 1:
The formulations presented in table 1 were corrected accordingly.
4. Results and discussion
Microdoughlab results:
Line 186: Significant differences were also observed for DSF results. This information was included in the discussion, as corrected by the reviewer.
Rheology results:
Line 248, Figure 3: The figure was amended, as corrected.
Line 254: "CO2" was amended as corrected.
Bread quality parameters results:
Line 272-273: The English language was checked, as suggested.
Line 285-286: The linear parameters A and B obtained by equation 2: Firmness = A * time + B, was clarified in Table 4.
Line 304: Table legend of figure 5 was corrected, as suggested.
5. Nutritional profile results:
Line 372-373: The sentence was reformulated and corrected accordingly to the reviewer's correction.
Line 347-377: The fats profile analysis was not performed. This paragraph was removed, as suggested.
Line 381: The reference “Reg. (CE), Nº 1924/2006; Dir. No 90/494 (CE)” was corrected as suggested by the reviewer.
Line 382: The sentence was removed as suggested.
Line 383-385: The paragraph was reformulated and corrected, as suggested by the reviewer.
Salt content:
The salt content is in accordance with the vigor legislation (Law nº 75/2009) for salt addiction (0.55 g of sodium / 100g bread).
6. Conclusion:
Line 392: GFB: it is not general, please specify you are referring to your experimental bread. The sentence was reformulated according to suggested by the reviewer.
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Considering all the suggestions proposed, we expect that the revised manuscript is clearer and organized, after following all fruitful suggestions and comments from the Reviewer 2.
Reviewer 3 Report
The Authors of the manuscript entitled "Improving the technological and nutritive properties 2 of gluten-free bread by fresh curd cheese enrichment" made an attempt to characterize the technological parameters and nutritional value of gluten-free bread enriched with curd cheese. However, the assumptions of the experiment, and thus the interpretation of the results, are questionable. First of all, the composition of the analyzed GFB is too complex, as it contains buckwheat flour, rice flour and potato starch. Each of these ingredients was replaced with curd cheese, so their mutual proportions change, which makes it difficult to interpret the results obtained, the number of variables is simply too large.
It is difficult to compare, for example, the colour parameters or the mineral content of the experimental GF breads with cheese with the control bread which contains more buckwheat flour. Buckwheat flour will have a significant impact on the analyzed parameters. Therefore, the effect of curd cheese alone on the dough and bread is difficult to determine due to the complex interactions between the recipe ingredients.
Moreover, the description of the methodology is very laconic. This makes it difficult to follow the analysis procedure and forces the reader to search the literature. At least a brief description of how the analysis was carried out should be added. Moreover, there is no SD in the texture results (Table 4). Performing the texture analysis in 3 replicates is not enough, the more so that large pores are visible in the bread cross-section image, which may additionally increase the variability of the results, therefore a greater number of repetitions of this analysis is required.
There is also no discussion or explanation why the content of the analyzed microelements (Fe, Zn, Cu and Mn) decreased in baked goods with curd cheese.
In addition:
- sample names require standardization as Authors sometimes use the abbreviations CB, CcB ect and CD, CcD elsewhere.
- if statistically significant differences are marked with different superscripts, then in all tables "a" should be the highest value, other ways of presenting results became difficult to trace ((Tab. 6).
English grammar and style should generally be improved throughout.
Author Response
Response to comments of reviewer 3.
All the changes were highlighted in blue color.
1. First of all, the composition of the analyzed GFB is too complex, as it contains buckwheat flour, rice flour, and potato starch. Each of these ingredients was replaced with curd cheese, so their mutual proportions change, which makes it difficult to interpret the results obtained, the number of variables is simply too large. It is difficult to compare, for example, the color parameters or the mineral content of the experimental GF bread with cheese with the control bread which contains more buckwheat flour. Buckwheat flour will have a significant impact on the analyzed parameters.
Undoubtedly, the buckwheat flour has a high effect on the flavor, color, nutritional profile of the bread, probably more than rice flour and potato starch. Rice flour has been widely proposed as an alternative for making gluten-free bread due to its hypoallergenic protein, soft taste, and white color (Torbica et al. 2010). However, since the rice-based bread presented low-quality attributes, in terms of volume and hard crumb (Locke et al. 2019), other alternatives from pseudocereal flour sources (buckwheat, quinoa, amaranth, etc..) have been employed to improve the technological and nutritional profile (Alvarez-Jubete et al. 2010). Nevertheless, considering that the field of gluten-free products manufacturing is a huge and important branch of research, due to their “functional and nutritional gaps” the search for new nutritional and functional alternatives bakery ingredients keeps going a deep theme of study. In our research work, the incorporation of curd cheese into a gluten-free bread dough was studied to evaluate the effect not only on the bread appearance and nutritional profile but also in technology properties, in which such positive and encouraging results were obtained, compared to control bread.
Even though the replacement of the curd cheese in a flours basis (100g) changed their proportions, the differences in color obtained reflects well the effect of the Cc additions compared to control bread (that contains more buckwheat flour), in terms of crust and in crumb color. The control bread has a lighter, less reddish, and more yellow crust color, and the crumb is darker, less yellow, and redness color. However, as the levels of Cc increased those patterns changed significantly in all parameters, and the differences are proportional to the Cc increments: the bread crust became darker, most probably due to the increased levels of protein derived from Cc additions, more red tone, and less yellow appearance. In opposite, the crumb looks lighter, reddish, and yellow.
In terms of nutritional profile, the same can be noticed, with a significant increment in protein levels, being higher by upper levels of Cc tested (20% w/w), compared to control bread. Based on mineral profiles, some of them were decreased by Cc addition, as is the case of potassium (K) and trace elements (Fe, Cu, Mn, and Zn), since their prevalence in buckwheat is higher than Cc, therefore was diluted by Cc addition. However, the levels of potassium (P), magnesium (Mg) and Ca, have significantly increased, reflecting the positive effect of curd cheese supplementation on gluten-free bread, which can have a good contribution to the human diet, especially for celiac people. The same improvements can be noticed to the improvements of after-baking quality parameters, especially for bread volume, softness, and staling rate (Figure 4, Table 4, and Figure 5).
Considering all the results obtained, the differences observed by successively curd cheese levels additions seem to be consistent with the Cc increments. Linear correlations presented in Figure 6 give additional support to these findings, showing that these differences observed are proportional to the levels of Cc added.
2. Therefore, the effect of curd cheese alone on the dough and bread is difficult to determine due to the complex interactions between the recipe ingredients.
The complex interactions between curd cheese chemical composition and recipe ingredients could be an interesting topic of future research, in order to figure out what kind of specific interactions are being established (e.g. by confocal laser scan assays), further enhanced during the baking stage, leading to these bread improvements. In fact, those interactions, most probably protein-protein interactions, and starch-protein interaction, possibly strengthening by the increments in minerals (e.g. calcium), undoubtedly resulted in a better bread appearance in terms of bread volume and crumb alveoli distribution. A lot of work has been performed in this field of research using protein sources and hydrocolloids that can support these findings (Demirkesen et al. 2010; Ziobro et al. 2013; Graça et al 2019; 2020)
3. Moreover, the description of the methodology is very laconic. This makes it difficult to follow the analysis procedure and forces the reader to search the literature. At least a brief description of how the analysis was carried out should be added.
The additional M&M description was provided, accordingly. Quoted references were included in which the original methods were described in more detail.
4. Moreover, there is no SD in the texture results (Table 4). Performing the texture analysis in 3 replicates is not enough, the more so that large pores are visible in the bread cross-section image, which may additionally increase the variability of the results, therefore a greater number of repetitions of this analysis is required.
All the methods described in this manuscript were performed in triplicates and in 3 different bread, one by each replicate. In addition, to assess the bread crumb firmness, triplicates of each 10-bread crumb firmness measurement repetitions were performed. The standard deviations of the triplicates results were included in the Table4.
5. There is also no discussion or explanation of why the content of the analyzed microelements (Fe, Zn, Cu, and Mn) decreased in baked goods with curd cheese.
The discussion of the trace minerals decrease was included in the nutritional profile section, as suggested by the reviewer.
6. Sample names require standardization as Authors sometimes use the abbreviations CB, CcB ect and CD, CcD elsewhere.
Samples' names and abbreviations were standardized, accordingly.
7. If statistically significant differences are marked with different superscripts, then in all tables "a" should be the highest value, other ways of presenting results became difficult to trace (Tab. 6).
In all results presented the superscript letter "a" express the data of the control bread.
6. English grammar and style should generally be improved throughout.
The English grammar was checked up throughout the whole manuscript.
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Considering all the suggestions proposed, we expect that the revised manuscript is clearer and organized, after following all fruitful suggestions and comments from the Reviewer 3.
Reviewer 4 Report
This is an interesting study about the role of fresh curd cheese in improving technological and nutritive properties of gluten-free bread. I have no major methodological comments. The study design is appropriate to the goal of the paper.
Author Response
Our research group would like to thank you for the comments on our manuscript.
Round 2
Reviewer 1 Report
Manuscript is correct and could be accepted for publication in Applied Sciences.
Author Response
Our research group would thank the comments and the improvement suggestion on our manuscript.
Reviewer 2 Report
Dear Authors,
Thank you for amending your manuscript according to my comments/suggestions.
Some aspects require your attention yet.
- Please, have the English language checked by a native speaker.
- Please, revise the English in line 409 – 410. The sentence sounds as if a reduction of 31.4% of carbohydrates occurred in CCB20%. Actually Table 6 shows that carbohydrate content decreased from 45.9 g/100g to 31.5 g/100g.
- Please, check again line 420. You mentioned “Dir. No 90/494”. In Eurlex you read that
90/494/EEC is Commission Decision of 26 September 1990 authorizing France provisionally to provide for derogations from certain provisions of Council Directive 77/93/EEC in respect of plants of Picea A. originating in the United States of America
Did you mean, by chance Council Directive 90/496/EEC of 24 September 1990 on nutrition labelling for foodstuffs? If so, please, mind that the 90/496 is no longer in force, with a date of end of validity: 13/12/2014. It was repealed by Regulation (EU) No 1169/2011.
My suggestion is to keep REGULATION (EC) No 1924/2006 and add the reference within the text and in the Reference list.
- Line 423-425. To make your result more sound and contextualized, my suggestion is to include a reference to studies analysing the dietary requirements of celiac people.
- Line 430: please, delete the reference Directive 90/494
- Line 443: the results from a technological point of view were indeed very interesting and promising, so in my opinion you can conclude that your study showed considerable improvements in bread quality. On the contrary, the conclusion about a considerable improvement of the nutritional profile of CCB20% is in my opinion not based on extensive data. Please, try to be more careful in stating “Considerable improvements in terms of […] nutritional profile”.
Author Response
Responses to comments of reviewer 2.
The changes along the manuscript were highlighted in a green tone.
1. Please, have the English language checked by a native speaker.
The English language was checked.
2. Please, revise the English inline 409 – 410. The sentence sounds as if a reduction of 31.4% of carbohydrates occurred in CCB20%. Actually Table 6 shows that carbohydrate content decreased from 45.9 g/100g to 31.5 g/100g.
The reduction of carbohydrates from 45.9 g/100g to 315 g/100g corresponds to a 31.4 % of reduction. The sentence was rewritten in accordance with the reviewer's suggestion.
3. Please, check again line 420. You mentioned “Dir. No 90/494”. In Eurlex you read that 90/494/EEC is the Commission Decision of 26 September 1990 authorizing France provisionally to provide for derogations from certain provisions of Council Directive 77/93/EEC in respect of plants of Picea A. originating in the United States of America.
My suggestion is to keep REGULATION (EC) No 1924/2006 and add the reference within the text and in the Reference list.
The regulations mentioned were corrected and included in the references list.
4. Line 423-425. To make your result more sound and contextualized, my suggestion is to include a reference to studies analyzing the dietary requirements of celiac people.
References were included showing the studies performed to fulfill the dietary requirements of celiac people, as recommended by the reviewer.
5. Line 430: please, delete the reference Directive 90/494
Directive 90/494 was deleted as corrected by the reviewer.
6. Line 443: the results from a technological point of view were indeed very interesting and promising, so in my opinion you can conclude that your study showed considerable improvements in bread quality. On the contrary, the conclusion about a considerable improvement of the nutritional profile of CCB20% is in my opinion not based on extensive data. Please, try to be more careful in stating “Considerable improvements in terms of […] nutritional profile”.
The sentence was reformulated as suggested by the reviewer.
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Considering all the suggestions proposed, we expect that the revised manuscript is clearer and organized, after following all fruitful critics from the reviewer.
Reviewer 3 Report
The Authors took into account the reviewer's comments and provide suitable explanation, however, few ambiguities still require clarification and comment from the Authors:
- Lactose is an important issue as celiac patients are often susceptible to secondary lactose intolerance due to alterations of lactase secretion resulted from the villous atrophy - please explain whether the tested curd cheese is a source of lactose, and add suitable discussion and reference in the introduction to explant this problem [for example Ojetti et al. Digestion 2005, 71, 106–110].
- in the Materials section, please describe how was the curd cheese produced? Was it made from fresh pasteurized milk in the process with bacterial culture and rennet added to clot the milk that was then cooked and pressed to release the whey? Or was it a fresh dairy product made by warming soured milk until the desired amount of curdling is obtained, which can be classified as fresh acid-set cheese? Method of production need to be described as in different countries and regions “curd cheese” and “cheese curds” means a different type of cheese, and in addition the production method has a decisive impact on the content of individual nutrients and minerals
- Line 74-78: I don’t see the need to write about whey if whey is a by-product and it will not be used in experimental gluten-free bread; instead I suggest that you describe the benefits of using just curd cheese;
- I suggest to provide the characteristics of the raw materials, in particular of curd cheese, please provide a description or a table with the basis chemical composition of experimental curd cheese as well as the content of basic minerals
- Even if a commercial curd cheese was used, please include the lactose content according to the manufacturer. In addition, what was the lactose content in the final product?
Author Response
Response to comments of Reviewer 3.
Changes along the manuscript were highlighted in yellow tone.
- Lactose is an important issue as celiac patients are often susceptible to secondary lactose intolerance due to alterations of lactase secretion resulted from the villous atrophy - please explain whether the tested curd cheese is a source of lactose, and add suitable discussion and reference in the introduction to explant this problem [for example Ojetti et al. Digestion 2005, 71, 106–110].
The curd cheese used was lactose-free. This information was included in the M&M raw materials description.
- in the Materials section, please describe how was the curd cheese produced? Was it made from fresh pasteurized milk in the process with bacterial culture and rennet added to clot the milk that was then cooked and pressed to release the whey? Or was it a fresh dairy product made by warming soured milk until the desired amount of curdling is obtained, which can be classified as fresh acid-set cheese? Method of production need to be described as in different countries and regions “curd cheese” and “cheese curds” means a different type of cheese, and in addition the production method has a decisive impact on the content of individual nutrients and minerals.+
The curd cheese is a co-product obtained by the thermal denaturation and subsequent precipitation of the soluble whey proteins. This information was included in the introduction section as well as in the M&M and it was produced and controlled by the industrial supplier.
- Line 74-78: I don’t see the need to write about whey if whey is a by-product and it will not be used in experimental gluten-free bread; instead I suggest that you describe the benefits of using just curd cheese;
Curd cheese is obtained from thermal denaturation of whey. Therefore, the benefits of this product derived from the functional benefits of whey proteins.
The description of the curd cheese benefits was included in the introduction section, as suggested.
- 4. I suggest providing the characteristics of the raw materials, in particular of curd cheese, please provide a description or a table with the basic chemical composition of experimental curd cheese as well as the content of basic minerals.
The detailed nutritional composition of the raw materials and the curd cheese was described in previous works and is already published; therefore, we direct the reader to the respective publication.
- Even if a commercial curd cheese was used, please include the lactose content according to the manufacturer. In addition, what was the lactose content in the final product?
Lactose sources were not included in GFB manufacturing. Therefore, the curd cheese bread obtained is lactose-free. Even if curd cheese had some residual lactose, the proportion of Cc in GFB is a further reduction by the dilution effect together with the other ingredients.
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Considering all the suggestions proposed, we expect that the revised manuscript is clearer and organized, after following all fruitful critics from the reviewer.
Round 3
Reviewer 2 Report
Dear Authors,
thank you for amending the manuscript according to suggestions.
The paper is now more suitable for publication.
Line 419: please, modify "specify" into "specifies".
Reviewer 3 Report
The authors took into account all reviewer's suggestions and comments. The revised manuscript by Graça et al. is clearer and in its current form is ready for publication
