Production and Evaluation of Yogurt Colored with Anthocyanin-Rich Pigment Prepared from Jabuticaba (Myrciaria cauliflora Mart.) Skin

Round 1

Reviewer 1 Report

Comments for author File: Comments.pdf

Author Response

Processes

Responses to the reviewers’ comments: Manuscript ID: processes-2170356

Title: Anthocyanin-rich pigment prepared from jabuticaba (Myrciaria cauliflora Mart.) skin by-product as a natural yogurt color additive

All comments suggested by the reviewers were carefully addressed and changes were done in the text accordingly, as explained below.

Reviewer #1

1. In the whole manuscript authors have used a significantly slight increase or significant slight decrease; please check whether slight is appropriate if results are significant at p=5%.

Answer: The authors thank you for all your comments and suggestions. We are sorry for this inaccuracy, the terms ‘slight’ were suppressed or written in another manner, considering the results are significant at p=5%.

2. The inclusion of positive control with synthetic colorant would improve the hypothesis and impact of the manuscript.  

Answer: Thank you for the suggestion. We agree that this could be a great contribution to the work, but unfortunately, the research project is concluded and we are not able to include the analysis of positive control. 

3. L12: commonly found may be replaced as commonly added. 

Answer: Done.

4. L 19 and 20: plz also mention whether these values are significant. 

Answer: Thank you for your review, the required information was added.

5. Keywords: have a scope of improvement

Answer: In addition to the keywords Functional food, Encapsulation, Colorant, Dye, and Food additive, we changed spray-dryer to Spray-drying and we included the keywords by-product,  Anthocyanin, Flavonoid and Dehydration.

6. L33-34: plz add reference if available

Answer: Included.

7. L43: please add a reference to support the statement

Answer: Included.

8. L58: please add data on the presence of anthocyanin content in jabuticaba skin?

Answer: The reference was included.

9. L96: plz mention the vacuum level and temp of cooling chamber

Answer: The aqueous extract reached room temperature naturally, and this information was added to the text.

10. L199-200: plz check the data with the statement

Answer: We are sorry for this inaccuracy, the term ‘greater’ was replaced with ‘shorter’ to be in accordance with the results in Table 1. 

11. L201: there is a significant difference, so please write it and the reason for this, could be some proteolysis, etc?

Answer: The discussion has been revised and modified to bring this information.

Author Response File: Author Response.docx

Reviewer 2 Report

The research manuscript by Pinto et al deals with the utilization of jabuticaba skin byproducts as a natural colorant in yogurt. The hypothesis is properly stated. The manuscript is written in easy-to-understand and read language.

However, to further improve it, I have the following suggestions as-

       i.          In the whole manuscript authors have used a significantly slight increase or significant slight decrease; please check whether slight is appropriate if results are significant at p=5%.

     ii.          The inclusion of positive control with synthetic colorant would improve the hypothesis and impact of the manuscript.  

Other observations are as follows-

   iii.          Abstract: I have the following observations in this section

       i.          L12: commonly found may be replaced as commonly added

     ii.          L 19 and 20: plz also mention whether these values are significant

   iii.          Keywords: have a scope of improvement

   iv.          L33-34: plz add reference if available

     v.          L43: please add a reference to support the statement

   vi.          L58: please add data on the presence of anthocyanin content in jabuticaba skin?

  vii.          L96: plz mention the vacuum level and temp of cooling chamber

viii.          L199-200: plz check the data with the statement

   ix.          L201: there is a significant difference, so please write it and the reason for this, could be some proteolysis, etc?

Thanks for giving me the opportunity to read your work. 

Author Response

Please kindly find the response in the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript reports the production, storage and consumers' evaluation of yoghurts produced with different amounts of an anthocyanin-rich extract produced from jabuticaba skin. The paper is well written and results are presented and discussed in a clear way, but I have some concerns that I explain below: 

Section 2.1 - The authors stated that potassium sorbate was added to yoghurts because it is a preservative. However, it has been of great value to produce a yoghurt only with jabuticaba skin extract to even value more the extract. Anthocyanins are known for their antioxidant activity and it would have been interesting to evaluate if the extract itself has the ability to replace the potassium sorbate. Moreover, it would have been interesting to evaluate the antioxidant activity (perhaps, using one of the following assays - DPPH, ABTS, FRAP or ORAC) of the produced yoghurts, the yoghurt with the extract and without potassium sorbate, and the extract alone. Therefore, I suggest the authors produce the extra yoghurt and test the antioxidant activity of all samples.

Line 199 - The authors stated that, according to the literature [21], "It was verified that greater storage times were associated to increased acidity and lower pH values". However, the current study reported an opposite trend. Do you have any explanation?

Table 4 - The authors have used a hedonic scale to evaluate the consumer's acceptance. In my opinion, Table 4 would be more informative if, for each attribute, it reported the frequency of each scale value. e.g. How many testers voted for 6? How many testers voted for 7? and so on. As it is, the reader does not have the whole picture because the authors just report a mean+-SD. Moreover, did you see any differences in product acceptance between male and female testers? What about age groups? Can you please inform the testers' age? Have you seen any differences between young and older testers?

For all the abovementioned reasons, I recommend major revisions to this manuscript. 

Author Response

Please kindly find the response in the attachment. 

Round 2

Reviewer 3 Report

Dear Authors,

Unfortunately, I do not have access  to the file you have uploaded with the answers to my comments .

Author Response

Processes

Responses to the reviewers’ comments: Manuscript ID: processes-2170356

Title: Anthocyanin-rich pigment prepared from jabuticaba (Myrciaria cauliflora Mart.) skin by-product as a natural yogurt color additive

All comments suggested by the reviewers were carefully addressed and changes were done in the text accordingly, as explained below.

Reviewer #3

Introduction

1. Line 46-49: The paragraph “Pigments based on anthocyanins present several desirable characteristics since they act as antioxidants and have numerous health benefits. Anthocyanins can interrupt or reverse carcinogenesis, acting on intracellular signaling molecules involved in cancer propagation and/or initiation” [4], which would be in line 40, after reference 2.

Answer: The authors thank you for all your comments and suggestions. The paragraph was moved as indicated.

2. Line 60- 63: The paragraph “Anthocyanins are water-soluble, which is desirable for pigment production. Recently their applications as natural color additives have increased as their color and stability properties have improved. Some factors can affect anthocyanin application such as product pH, presence of metals, exposure to light, high temperatures, oxygen, and enzymes”, would be in line 57, after reference 6.

Answer: The paragraph was moved as indicated.

3. Line 68: Jabuticaba powder extracts have been used only in the fresh sausage as a food additive? Would be mentioned if these powders have not been used in yogurt applications? This could be highlighted as the novelty of this research

Answer: Few works mention the application of jabuticaba powder in yogurts, but the present manuscript is not the first one.

4. Line 57-58: The paragraph “The anthocyanin-rich pigment extracted from jabuticaba skin could therefore be employed in yogurts” would be in line 71

Answer: The paragraph was moved as indicated.

5. Line 72: The objective is not clear, and the wording should be improved

Answer: The text was reviewed to bring more information on the objective of the work.

6. Line 75: change “Rheological behavior” for “rheological properties”. Change “ to verify” for “ to evaluate the potential substitution…..

Answer: Done.

Materials and methods

7. For yogurt preparation the plain yogurt was mixed with the powdered extract at the concentration levels 0.5; 1.0; 1.5 and 2.0 g/100 g (w/w). A control sample without extract 103addition was also prepared for comparison. However, the sensory analyses were evaluated for yogurt containing 0.5 g/100 g (w/w) of pigment and 0.4 mL/100 mL (v/v) of flavor additive according to the results of a preliminary assay. In this context, the authors should explain or justify why were used the powdered extract at concentration levels higher than 0.5 g/100g (w/w). They did not have good sensory acceptability.

Answer: The authors thank you for this comment. The preliminary assay was made before the sensory acceptance considering the similarity of color between the yogurt added to jabuticaba extract and commercial berry-flavored yogurt. The concentration level of 0.5 g/100g (w/w) as well the other concentration levels (1.0, 1.5, and 2.0 g/100g (w/w)) was applied to the yogurt to evaluate the powder influence on pH, total solids content, anthocyanin content, instrumental color throughout the product shelf-life and rheological properties.

Results and discussion

8. Line 188: no differences significative were observed at the concentration level of 1g/100g concerning control. Significant differences were observed only between the control and treatment with a concentration of 2.0g/100g. Line 190: change “then” for “concerning” or “then”. Line 191: change “like” for “similar”

Answer: We are sorry for this inaccuracy. The information and the terms were corrected.

9. Line 201: The authors indicate that after the 7th day, pH values were slightly greater than the initial values (except for the 1.5 g/100 2.0g extract concentration). However, significant differences were observed for all treatments concerning the initial pH (Time 0), except for the 1.5 g/100 g extract concentration

Answer: The paragraph was modified to bring more information on the pH variation during storage.

10. Line 216: The addition of 0.5, 1.5, and 2.0 g/100g of extract did not show significant differences in anthocyanin content between T0 and T14. The authors should go deeper into the discussion of this point

Answer: This sentence was rewritten to indicate the decrease in the biological activity of the compound and the variation in the product's color.

11. Line 242: The authors should indicate that the value “a” changed significantly during storage for all systems.

Answer: Done.

12. Line 289: The authors should explain under which possible mechanism the extract addition to yogurt could disrupt the casein gel network

Answer: A mixer (Philips Walita RI1364 400W) was employed to blend the extract and potassium sorbate with the yogurt, disrupting the gel (lines 140-142 of Material and Methods).

13. Line 308: The authors indicate that only yogurt samples containing 0.5 g/100 g of jabuticaba skin powdered were evaluated for sensory analyses because they showed greater stability during storage (lower anthocyanin degradation). However, according to the results, the addition of 0.5, 1.5, and 2.0 g/100g of extract did not show significant differences in anthocyanin content between T0 and T28. Besides,

Answer: We received this review point missing its conclusion, so unfortunately, we are not able to answer back the suggestion.

Author Response File: Author Response.docx

Round 3

Reviewer 3 Report

Dear Authors,

In my first report, I raised some questions not addressed yet in this new manuscript version. 

Section 2.1 - The authors stated that potassium sorbate was added to yoghurts because it is a preservative. However, it has been of great value to produce a yoghurt only with jabuticaba skin extract to even value more the extract. Anthocyanins are known for their antioxidant activity and it would have been interesting to evaluate if the extract itself has the ability to replace the potassium sorbate. Moreover, it would have been interesting to evaluate the antioxidant activity (perhaps, using one of the following assays - DPPH, ABTS, FRAP or ORAC) of the produced yoghurts, the yoghurt with the extract and without potassium sorbate, and the extract alone. Therefore, I suggest the authors produce the extra yoghurt and test the antioxidant activity of all samples.

Table 4 -  Did you see any differences in product acceptance between male and female panelists? What about age groups? Can you please inform the panelists' age? Have you seen any differences between young and older panelists?

Author Response

Reviewer #3 – Round 3

1. Section 2.1 - The authors stated that potassium sorbate was added to
yoghurts because it is a preservative. However, it has been of great value to
produce a yoghurt only with jabuticaba skin extract to even value more the
extract. Anthocyanins are known for their antioxidant activity and it would
have been interesting to evaluate if the extract itself has the ability to
replace the potassium sorbate. Moreover, it would have been interesting to
evaluate the antioxidant activity (perhaps, using one of the following assays
- DPPH, ABTS, FRAP or ORAC) of the produced yoghurts, the yoghurt with
the extract and without potassium sorbate, and the extract alone. Therefore,
I suggest the authors produce the extra yoghurt and test the antioxidant
activity of all samples.
Answer: The authors thank you for all your comments and suggestions.
Unfortunately, the research project is concluded and we are not able to
include the analysis of a yogurt sample without the preservative potassium
sorbate and check the effect of the jabuticaba skin powder as an antioxidant.
Certainly, these results would add a lot of value to our work; we are very
grateful for the suggestion.
1. Line 199 - The authors stated that, according to the literature [21], "It was
verified that greater storage times were associated to increased acidity and lower
pH values". However, the current study reported an opposite trend. Do you have
any explanation? 
Answer: We are sorry for this inaccuracy, the term ‘greater’ was replaced
with ‘shorter’ to be in accordance with the results in Table 1. 

1. Table 4 - The authors have used a hedonic scale to evaluate the
consumer's acceptance. In my opinion, Table 4 would be more informative if, for
each attribute, it reported the frequency of each scale value. e.g. How many testers
voted for 6? How many testers voted for 7? and so on. As it is, the reader does not
have the whole picture because the authors just report a mean+-SD. Moreover, did
you see any differences in product acceptance between male and female testers?

What about age groups? Can you please inform the testers' age? Have you seen
any differences between young and older testers?
Answer: Unfortunately, we don’t have information on the panelists’ age or
gender. Table 4 was modified to report the frequency of each scale value, as
suggested. Certainly these results would add a lot of value to our work; we
are very grateful for the suggestion.

Author Response File: Author Response.docx