Waste to Wealth of Apple Pomace Valorization by Past and Current Extraction Processes: A Review

No

Comments/suggestions

Answer

1

The manuscript has reviewed that common and new technologies to obtain valuable products from apple pomace which has came from production of apple juice or cider. Especially, emphasis of new and green technique for such purpose during the text is very important and will contribute the literaure. Firstly, the abstract can rewrite. Some techniques can be mentioned in this section. Other comments can be listed as:

Thank you for your comments and suggestions, the abstract has already been revised and rewritten.

2

-In the lines 85 and 89, banana production has been written, is that correct? I dont understand what is relation with text content.

Sorry for the mistake, the sentence has already been revised

3

-Also, I can not see Figure 2. 

The caption of figure has already revised as shown in track change format

4

-Lines 133, what is GA?

This part has already been revised as shown below:

the methylated ester of 1,4-linked galacturonic acid (GA) attaches to a few rhamnose residues in the main chain and arabinose, galactose, and xylose in the side chains

5

Some abbreviations were used before openings, it should be vice versa. For example DPPH at line 164.

This part has already been revised

6

The reference style should be revised through the text. There are a lots of errors. (Line 164, 170, 317 and many others)

This part has already been revised

7

HSV2 was written two times (line 169). I think, the abbreviations should be controlled.

This part has already been revised

8

Lines 210-2015 need a reference.

The reference has already been added

9

Figure 1 has two graphics, should be indicated what they are refering to by letters in the caption of the figure.

The figure 1 has already been revised.

10

Section "Apple pomace ext. by MAE" can contain some generally preferred solvents in the method.

The dielectric susceptibility of both the liquid and the solid plant matrix substantially influences microwave radiation. Therefore, water is more favourable solvent to extract the apple pomace due to high polar compounds, where is nontoxic and green solvent [54].

11

RSM has been widely used for optimizing conditions to obtain different bioingredients from apple pomace which it can be also seen in the text. Therefore, as a reader, I would like to see a summary table which contain RSM techniques used for such purpose, such as, what is the extraction method and which RSM design matrix time preferred. The factors and the response etc. with references of course. Such table will definitely strengthen of the text. 

Thank you very much for your suggestion. I am really appreciated. Table 1 has already been added related to the variable and responses in order to valorise apple pomace using different method extraction. 

No

Comments/suggestions

Answer

1

- The manuscript described a lot about the extraction methods (more than valorization), the title should be adjusted to represent the work clearly.

The extraction has been stated in the title. hopefully, the readers can understand that the valorization of apple pomace using the extraction method.

2

In the Introduction (Line 35), 'Agro-industrial wastes' are...

The agricultural wastes such as peanut skin and banana peels have been valorized in our group since 2017, moving towards a “zero waste” economy to obtain products and substances that, due to their nature, will interact with traditional ones, reducing emis-sions and contributing to healthier material and commodity output.

3

The authors described about apple production, but some sentences still showed 'bananas', please revise.

Sorry for the mistake, the sentence has already been revised

4

In this work, the authors should show the literature reviews about the high-value active compounds found in apple pomace (not only pectin) and their estimated contents or quality (purity) to show their worthiness. 

Thank you very much for your suggestion. This part has already been revised.  the antioxidant activity has been added to the manuscript.

5

Some abbreviations should be shown with the full name, such as galacturonic acid (GA) (Line 113),  Ultrasound-assisted extraction (UAE) (Line 297).

This part has already been revised

6

- MAE, UAE already means 'extraction', no need to use MAE extraction or UAE extraction. Please check all

This part has already been revised

7

The author should add one table that compares all extraction methods, products, and their results (DPPH scavenging activity or yield or types of phenolic compounds).

Thank you very much for your suggestion. I am really appreciated. Table 1 has already been added related to the variable and responses in order to valorise apple pomace using different method extraction. 

8

All explanations should be clear, do not use too many compound sentences.

This part has already been revised

9

Conclusion should not focus on only pectin, other phenolic compounds should be added (main compounds in apple pomace).

The phenolic compounds also has been added in the conclusion part