Utilization of Mango, Apple and Banana Fruit Peels as Prebiotics and Functional Ingredients

Round 1

Reviewer 1 Report

This manuscript describes an interesting and complex research to assess the chemical composition, functional properties and the prebiotic effects of three major tropical fruit peels (apple, banana and mango). Also, it is an advanced topic with an emphasis to to demonstrate the potential applications of FPP in the food and pharmaceutical industries as functional ingredients. The findings of this study make a significant contribution that reveal that small amount of apple, banana and mango peel powder could be sucessefully used as prebiotics to enhance the growth of lactic acid bacteria.
Overall, this study is well-designed the methodology are appropriate and there are provided relevant explanations for the obtained results. The conclusions have been well formulated, being supported by the obtained results. The references are relevant for the research topic. This work is well-written in a standard English, clear and unambiguous.

There are a few points mentioned below which need to be addressed before publication:

- Please, check more carefully the style requirements of the journal;
- In the section Results and discussions, don’t use the standard deviation in text, when you discuss the obtained results (the average value is enough). The means ± standard deviation can be seen in Tables 1 and 2;
- Please, correlate the values from text with those presented in tables (Ex. 0.542 ± 0.035 to 0.611 ± 0.018 in text and 0.54±0.04; 0.61±0.02 in Table). Data must be presented in both tables and text with the same number of digits. I recommend you to present data (average values and standard deviation) with less number of significant digits.

Author Response

We have thoroughly revised the manuscript “Utilization of mango, apple and banana fruit peels as prebiotics and functional ingredients” and implemented all reviewers’ comments and suggestions.

All revised sections have been marked with the Track Changes Function as recommend. Additionally, a summary table addressing each comment based on point-to-point revision has been included.

Thank you for your consideration of this manuscript. 

A point-by-point response to the reviews’ comments:

Ref.: Manuscript ID: agriculture-1252386

Type: Article

Article Title: Utilization of mango, apple and banana fruit peels as prebiotics and functional ingredients

We thank all reviewers and editors for providing detailed and constructive comments.

Reviewer 2 Report

The manuscript deals with utilization of mango, apple and banana fruit peels as prebiotics and functional ingredients . In this research the authors investigated chemical composition, functional properties and the prebiotic effects of three major tropical fruit peels (apple, banana and mango).

The thematic is interesting, and the results present a step forward in the knowledge. The quality of the presentation is good but the depth of discussion of some of the results needs improvement.

Figure 2 is not available as Supplementary materials too.

It is suggested to review the manuscript according to the comments below.

Review comments:

Attention: the references reported throughout the manuscript are many time in different form, the authors choose a single version: “Author name, et al.” For example: Romelle, et al. [22] in 233, is OK ; “by Romelle, Rani and Manohar [22]” in 252, could be changed

1. Introduction :

Line 31: Is enough report only the number of the reference or, if you prefer, it is necessary add “by reported in Kodagoda and Marapana [1].”

Line 59: What criteria the authors applied to report “at full maturity”? Do you have any data on sugar content or titratable acidity?

2. Materials and Methods :

Paragraph “2.4 Preparation of fruit peel powders (FPP)”: the authors need change it in italics

Line 68: How match fruit were selected for each cultivar?

Line 72: Which is the reason to select size 250 μm?

Line 80-84: The text is written in italics, the authors will have to correct it

Line 92-99: Move the paragraph of TFD after Protein, according to express in Tab.1

Line 115: the abbreviation of Total polyphenolic content is TPC, the authors correct it throughout the manuscript

Line 124 and 142: change “fruit peel extracts” in “fruit peel powder extracts”

Paragraph “2.9 Activation of probiotic cultures”: move it inside “Assessment of the FPP prebiotic effect” and change the numeric sequence

3. Results and discussions :

All the data reported could be with 2 decimal number, change in lines 218, 227, 228, 229, 234, 240, 249, 251, 257, 258, 259, 270, 271, etcetera

Line 218: Change “from 0.542 ± 0.035 to 0.611 ± 0.018 in BPP and MPP, respectively.” In “from 0.542 ± 0.035 to 0.611 ± 0.018 and add the unit  

Line 237-238: The authors sad “FPP can be used as natural source of Ca, Zn and Fe to improve these mineral contents in some diets”,  according this sentence do you have any data on yours matrix?

Line 248:  Add a reference for the sentence “apples in general don’t contain large amounts of fat”

Line 252: add unit in (2.80 ± 0.17)  (%)

Line 254: “It is vital to mention here that most fruits are low in protein and fat contents. “, better explain it and add reference

Line 257-258: Change “mango peel” in MPP, “Apple peel” In APP, “banana peel” in BPP

Line 260: no indention

Line 270: In “39.562±1.847” the authors need to add a space

Line 286: Add unit for flavonoids contents data: mg QE/g dw

Line 290: Add unit in “for BPP (6.13 ± 0.25) and APP (10.82 ± 0.51)”

Lines 291-293: the authors better explain this sentence: “It could be attributed to the concentration of extraction solvent used because variations in the content of polyphenols extracted from plant matrices are determined by the level of concentration of extraction solvent” and add reference

Line 293: Hayouni`, 2007 `#82. To correct

Lines 294-298: Attention! There is a repetition of sentences… from 288-293

Lines 299-304:  The sentence reported to explain the results are not clear, please change in a new and clearer version

Line 308: “byroducts” , correct by-products

Line 312: Add unit in  “DPPH and ABTS (5.51 ± 0.45) and (12.37 ± 2.71) respectively “

Line 324: Change in 5.941 ± 0.294

Line 349: “finding of [16].” To correct

Line 379: “The hue value” change in “The hue angle value”

In Table 2 change “Hue” in “Hue Angle” and add unit (h°); moreover, add unit for Chroma (C)

In 3.4. Prebiotic effects of tested fruit peel powder the Bifidobacterium animalis subsp. lactis is expressed as Bb-12 different from BB-12 indicated in 2.1. Fruit peels and probiotic cultures. choose which one and correct it throughout the manuscript

Line 410: Change “constantthroughout” in constant throughout

Line 413: “sugar contents” ? correct is “carbohydrates content”

Line 422: Fig. 2? there is no figure 2, add it

Figure 3. It’s no well visible

Line 487: Change “cfu/ml” in “log CFU/ml”

Supplementary Materials :

Supplementary materials are not available

References :

Greater attention is suggested in reporting bibliographic references; some errors have been found such as:

The publication year for

 “Serna-Cock, L.; García-Gonzales, E.; Torres-León, C. Agro-industrial potential of the mango peel based on its nutritional and 550 functional properties. Food Reviews International. 2015, 32, 364-376. “

 is 2016, the authors need to change it

The publication year for

Helkar, P.B.; Sahoo, A.; Patil, N. Review: Food industry by-products used as a functional food ingredients. International Journal 535 of Waste Resources 2016, 6, 1-6.

is 2017, the authors need to change it

The publication year for

Bujna, E.; Farkas, N.A.; Tran, A.M.; Dam, M.S.; Nguyen, Q.D. Lactic acid fermentation of apricot juice by mono- and mixed 644 cultures of probiotic Lactobacillus and Bifidobacterium strains. Food Science & Biotechnology. 2017, 27, 547-554.

is 2018, the authors need to change it

Author Response

We have thoroughly revised the manuscript “Utilization of mango, apple and banana fruit peels as prebiotics and functional ingredients” and implemented all reviewers’ comments and suggestions.

All revised sections have been marked with the Track Changes Function as recommend. Additionally, a summary table addressing each comment based on point-to-point revision has been included.

Thank you for your consideration of this manuscript. 

A point-by-point response to the reviews’ comments:

Ref.: Manuscript ID: agriculture-1252386

Type: Article

Article Title: Utilization of mango, apple and banana fruit peels as prebiotics and functional ingredients

We thank all reviewers and editors for providing detailed and constructive comments.

Reviewer 3 Report

The manuscript "Utilization of mango, apple and banana fruit peels as prebiotics and functional ingredients"  investigate the use of  apple, banana and mango peel powder  as potential enhancer of the growth of lactic acid bacteria.

The manuscript is rather interesting, however, there are some points which have to be clarified and /or adjusted :

1) in all the manuscript the same style should be used, in particular in the various section and subsection 

2) lines 80-84 why are reported in italic?

3) in the paragraph 2.3 the authors describe the procedure for preparing fruit peel powders (FPP)and the stored condition. Why in the investigation of the FPP composition the samples are exposed at 102 C as pretreatment (section 2.4)?

4) I suggest to move create an indipendent section for the extraction procedure

5) The results and discussion part is acceptable and the authors refers to previos works to discuss the results. However, the variability in the composition of the peels is affected from the geography and the fruit strain and it should be considered. 

6) in the line 509-511 the authors state that "the antioxidant capacities of the FPP confirmed that the agri-food wastes could make substantial contribution towards the commercialization of these peels as food and feed ingredients"

have you considere the impact which the food processing can have in the antioxidant activities?

7) quality of the figure should be improved

Author Response

We have thoroughly revised the manuscript “Utilization of mango, apple and banana fruit peels as prebiotics and functional ingredients” and implemented all reviewers’ comments and suggestions.

All revised sections have been marked with the Track Changes Function as recommend. Additionally, a summary table addressing each comment based on point-to-point revision has been included.

Thank you for your consideration of this manuscript. 

A point-by-point response to the reviews’ comments:

Ref.: Manuscript ID: agriculture-1252386

Type: Article

Article Title: Utilization of mango, apple and banana fruit peels as prebiotics and functional ingredients

We thank all reviewers and editors for providing detailed and constructive comments.

Round 2

Reviewer 2 Report

line 94-95: right formatting?

line 119: "An aliquot 25 µl () was mixed..." correct in "An aliquot 25 µl was mixed.."

line 229: cut "in BPP and MPP, respectively", because if you speack about a range you consider all the sample : BPP, MPP and APP

Author Response

A point-by-point response to the reviews’ comments:

Ref.: Ms. No. 1252386

Article Title: Utilization of mango, apple and banana fruit peels as prebiotics and functional ingredients.