Effects of Processing and Storage Conditions on Functional Properties of Powdered Blueberry Pomace

Round 1

Reviewer 1 Report

The Authors have modified the paper according to the comments of reviewers improving the quality and readability of the paper.

Author Response

Authors thank again the reviewer for the effort made in rechecking that the manuscript meets the quality requirements of the journal. 

Reviewer 2 Report

The authors have clarified all the aspects discussed in my review report of the previous submission (sustainability-1303871), and have corrected the errors/ improved the manuscript according to my previous comments.

Author Response

Authors thank again the reviewer for the effort made in rechecking that the manuscript meets the quality requirements of the journal. 

Reviewer 3 Report

Resubmitted manuscript entitled “Impact of processing and storage on the functional properties of a powdered ingredient obtained from blueberry pomace” by Calabuig et al carries something interesting contents. Unfortunately, it's not yet in a state of sophistication. The reviewer would request to author will rewrite it again.

About Title

[original] Impact of processing and storage on the functional properties of a powdered ingredient obtained from blueberry pomace → [proposal] Effects of processing and storage conditions on functional properties of powdered blueberry pomace

About constriction

[original]

3.1. Effect of air drying temperature and granulometry on physico-chemical properties and antioxidant capacity of dried blueberry pomace

3.2. Prebiotic effect preliminary assay: powders influence on lactic acid bacteria growth

3.3. Evolution of blueberry pomace powders properties during storage

→

[proposal]

3.1.Effects of processing condition on functional properties of powdered blueberry pomace (PBP)

3.1.1 antioxidant properties

3.1.2. physico-chemical properties

3.1.3. bacterial growth effect

3.2. Effects of storage condition on functional properties of PBP

3.2.1 antioxidant properties

3.2.2. physico-chemical properties

About Abstract and Conclusion

Must totally rewrite

Author Response

Authors thank again the reviewer for the effort made in rechecking that the manuscript meets the quality requirements of the journal. Authors’ responses to the reviewer suggestions are listed in the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Nothing

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

I have reviewed the first revision of paper, entitled "Impact of processing and storage on the functional properties of a powdered ingredient obtained from blueberry pomace". First of all, I would like to say that i find your paper coherent with the scope of the Sustainability journal. The abstract and conclusions is clear and adequate and the English language used is acceptable. But I want you to make some additions or corrections. In particular the need for this study should be expanded. You should clearly identify the gaps on the literature to justify this work. For the whole article, recent studies in the literature should be added. So, it is heavily recommended to enriching the sections of the paper by adding good documents.

Reviewer 2 Report

The manuscript is interesting since it analyses the effect of drying temperature and milling on the physicochemical and antioxidant properties of blueberry pomace. However, the manuscript has important errors and mistakes. Additionally, both, experimental design and statistical analysis are no correct. Therefore, my recommendation is that the manuscript cannot be published in Sustainability.

Major Comments:

• The main drawback is the experimental design. According to what the authors state in the material and methods (lines 72-80), and not specifying the experimental design here or in any other site, nor in the statistics section, it is understood that from the same pomace, an (n = 1) dried at 60 ºC and another (n = 1) at 70 ºC sample were obtained. In addition, after drying at 70 ºC, 2 different degrees of milling were carried out, one (n = 1) fine and the other (n = 1) coarse. Then, in the respective analytics it is specified that the analyses are made in "triplicates" or "five replicates", but this is false. The fact of doing an analysis several times of the same sample in no case can be considered as several replicates! True replicas are only when they are analysed from various samples obtained in the same way and under the same conditions. Therefore, the results derived from this study are not representative, since according to the authors, when only drying (with each of the conditions) or milling (with 2 intensities) only once cannot be considered replicas, for what there is an important bias in the results obtained. At least, triplicate drying and milling processes should be carried out. Then, “triplicates” from all the samples obtained should be analysed. Additionally, in the statistical section, the authors should be clearly indicated the complete experimental design (like: a total of …. samples were used in this experiment. … samples from each drying temperature X …drying process and … samples from 70ºC drying X 2 different milling grades X …replicas of milling process…)
• Also, statistical analyses are incorrect. In table 1, the authors include two different statistical analyses. One comparing P and DP60-DP70 (lowercase letters; effect of drying temperature) and another comparing DP70 and CP-FP (capital letters; effect of milling). However, in tables 3, 4 and 5, the effect of milling is not included in the statistical analysis and not reported in the tables, although the authors “discuss” or “state” it in the text (e.g. lines 365-366: “milling did cause a significant decrease”). This is an important mistake. Additionally, in any case, a statistical section of material and methods nor in the table footnotes the authors indicate the posthoc test used to compare the means. The authors also indicated that they did a correlation between DPPH and monomeric anthocyanins (lines 372-373) but they did not indicate this in the statistical section of the material and methods.
• Lines 73-75: Include the time required for “drying blueberry pomace” using 60 and 70ºC. for example, “…dried at 60 ºC (during …hours) and 70 ºC (during …hours)…”.
• There are some results that should be discussed more in-depth. For example:

Lines 215-216: “a slight increase in water activity was observed after milling”. Why? Discuss and compare the results whit other authors.

Lines 237-239: “…probably due to the increase…than 0.3.” The authors only make this claim, but they do not discuss anything, nor do they support anything with references. Contrary to what the authors comment, could the fact that the red colour decreases in DP70 be related to greater oxidation due to the increase in temperature? Please properly discuss this and support all claims with references.

Lines 317-319: “However, the emulsifying activity… [41, 42].” Why? What could be due to these lower values??? The authors should properly discuss this aspect. Everything must be supported by the results and conclusions obtained by the other authors.

Lines 245-248: “This fact could be…digestibility”. Include a reference to support this statement.

Carefully describe and discuss the effect of milling on the parameters reported in table 4 and table 5. It may be that storage affects some parameters more in one degree of milling than another. Or that does not affect. But this must be duly discussed, whereas now this aspect is hardly discussed. Please, discuss this aspect after correct the statistical error in the table.

• Table 1: The units must be deleted from the title, and must be included next to the parameter in the table, as the authors did in table 2. Additionally, all abbreviations must also be deleted from the title, and must be described in the table footnotes, not the title. Please, verify and correct if appropriate the units of fibre fractions. In the title, the authors reported that the “fibre fractions content is expressed as “g/g dry matter”, while in the table they specify in all cases “%”.
• Table 2: All abbreviations must be deleted from the title, and must be described in the table footnotes, not the title. Also, the number of replicates should be placed in the table footnotes. If the DP70 was used as the starting point for the elaboration of the FP and CP, and as it is done in other parameters, why was it not included in this table? Please include the values of these parameters for the DP70 and compare how the sample varies without milling (DP70) and with 2 different levels of milling (CP & FP).
• Table 3: The units must be deleted from the title, and must be included next to the parameter in the table, as the authors did in table 2. Additionally, all abbreviations must also be deleted from the title, and must be described in the table footnotes, not the title. Why is the table layout different from the first 2 tables? This makes no sense. PLEASE, FOLLOWING THE LAYOUT OF TABLES 1 AND 2, PUT THE PARAMETERS IN ROWS AND THE SAMPLES IN COLUMNS. Also, and as mentioned before, include the "statistic letters" comparing the effect of milling degree, between batches DP70, CP and FP.
• Table 4: The units of moisture content must be deleted from the title, and must be included next to the parameter in the table. Additionally, all abbreviations must also be deleted from the title, and must be described in the table footnotes, not the title. ALSO, ADDITIONALLY TO THE EFFECT OF STORAGE, INCLUDE THE "STATISTIC LETTERS" COMPARING THE EFFECT OF MILLING DEGREE, BETWEEN BATCHES CP AND FP FROM EACH STORAGE WEEK.
• Table 5: The units must be deleted from the title, and must be included next to the parameter in the table. Additionally, all abbreviations must also be deleted from the title, and must be described in the table footnotes, not the title. ALSO, ADDITIONALLY TO THE EFFECT OF STORAGE, INCLUDE THE "STATISTIC LETTERS" COMPARING THE EFFECT OF MILLING DEGREE, BETWEEN BATCHES CP AND FP FROM EACH STORAGE WEEK.
• In ALL Tables. DECIMALS MUST BE CORRECTED!!. All values less than 1 must have between 2 and 3 decimal places, as appropriate. Values between 1 and 10 must have 2 decimal places. Values between 10 and 100 must have 1 decimal place, while all values greater than 100 do not need to use decimals. This comment should be applied both for the mean values and for the deviations. In case of extremely small deviations, up to 4 decimals can be used. Correct all tables (and text if applicable) according to this comment.
• In ALL Tables. Include in the “statistical footnotes” the posthoc test used in statistical analysis.
• Why is the table layout different from the first 2 tables? This makes no sense. PLEASE, FOLLOWING THE LAYOUT OF TABLES 1 AND 2, PUT THE PARAMETERS IN ROWS AND THE SAMPLES IN COLUMNS. Also, and as mentioned before, include the "statistic letters" comparing the effect of milling degree, between batches DP70, CP and FP.
• Lines 255-263: The authors must clearly indicate (with numbers; mean and deviation) the mean particle size of each of the samples analysed. The graph is very visual, but it is impossible to know what the average size of each of the samples is. It must be indicated numerically in the text, and state how much this size decreases, not just indicate "that it decreases".
• Lines 516-517: “Oil interaction properties and emulsifying activity of the powders obtained ARE NOT OF INTEREST”. WHAT? Why “are not of interest”??. If they are not of interest, why have the authors analysed them? Please rewrite this sentence.
• Lines 518-520: The number of samples is very low, and the authors did not replicate the study. Therefore, the results obtained are not representative. So the authors cannot conclude this, since the results obtained are not representative due to the wrong experimental design.

Minor Comments:

Line 1: Specify “Article” in the type of paper section.

Line 24: The keywords “blueberry pomace” and “storage” are in the title. The authors should not use words included in the title as keywords. Please, change them.

Line 55: Change “physical-chemical” by “physico-chemical”, following the same nomenclature used throughout the text (e.g. line 86; Physico-chemical).

Line 55: Please, delete the comma after “et al.,”. Revise all manuscript and correct this error throughout the text (lines 57, 70, 123, 126, etc.).

Line 174: “was mixed with each buffer…” specify the amount of each buffer added.

Line 183: Put “+” in superscript.

Lines 202-205: As reported in previous suggestions, the statistical section should include all experimental designs and all samples used in the study. Also, the posthoc analysis used in the statistical treatment and the correlation test.

Line 211: “Correct DP60” as “DP70” in the sentence “…70 ºC (DP60)…”

Line 324: “…, the content in peel being higher than in the juice”. This sounds wrong; something is wrong with the sentence. Please rewrite it.

Line 492: Correct “[65][66]” as “[65, 66]”.

Line 639: Please, as the authors said include “the pages and volume” in reference 43.

Reviewer 3 Report

The paper entitled “Impact of processing and storage on the functional properties of a powdered ingredient obtained from blueberry pomace” by Laura Calabuig et al described antioxidant properties, water-oil interaction properties, and their stabilities of blueberry pomace powder prepared by combining air-drying with milling. I carefully read through whole manuscript, as the result, I have reached a conclusion that this paper should not be acceptable for publication at the moment. As the latest scientific paper, most new discoveries have been added to understand how, when, where and how the knowledge gained from this manuscript can help further advance the advanced use of agricultural by-products. I sincerely declare I have not any conflicts of interest.

• Such studies require researchers to isolate and identify active compounds.
• Some of the prebiotic effects may be of interest to the reader, though it was a proviso with preliminary research results.