Optimized Single-Step Recovery of Lipophilic and Hydrophilic Compounds from Raspberry, Strawberry and Blackberry Pomaces Using a Simultaneous Ultrasound-Enzyme-Assisted Extraction (UEAE)
, Cornelia Landolt 1, Karine Grenier 1, Sandrine Périno 5, Tan-Sothéa Ouk 1 and Naïma Saad 1,*Round 1
Reviewer 1 Report
Davidson et al. described an ultrasound-enzyme-assisted extraction (UEAE) to extract simultaneously the hydrophilic and lipophilic compounds from three berry pomaces (raspberry, strawberry and blackberry) after a selection of the enzyme useful for recover, in an aqueous medium, the highest yields of polyphenols and oil. The optimized procedure is more efficient than conventional extractions which use organic solvents. Polyphenols were analyzed by UPLC-MS/MS and the identified compounds are reported in Table 4. The authors should include in the paper (or in a supplementay file) the chromatographic profiles of each extracts before publication of the paper.
Minor editing of English language is required
Author Response
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Author Response.pdf
Reviewer 2 Report
The manuscript by Davidson M. et al. is devoted to optimizing the extraction of lipophilic and hydrophilic compounds from berries using enzymes and ultrasound. The work looks very voluminous, a significant amount of experimental data is presented. The topic is interesting and important. It consists in the development of approaches to reduce waste in the processing of renewable plant materials and obtain valuable products.
The main question that the authors should answer is: what does the proposed method give? Enzymes are rather expensive reagents, and their effect on completeness of extraction is doubtful. This will lead to a significant increase in the cost of the final product with a high consumption of the enzyme (1-2% by weight of the raw material). What will be observed during the extraction of these berries in completely similar conditions (pH 8), but without the addition of enzymes? In my opinion, this comparison is not given in the manuscript, but the pH level can have a key effect. The authors need to prove that enzymes are necessary.
Table 3 does not show any advantages of the proposed method over extraction with organic solvents. The increase in protein content in the extracts is probably caused by the use of significant amounts of enzymes, and the ash content increases due to the need to use buffers to control pH. Other indicators are comparable and even decrease in some cases.
The manuscript also requires technical corrections. For example:
- Line 181. “in section 0”. Line 304. “(see sections 0 and 0)”. Check all text.
- Lines 49, 72, 991. Need to remove "..."
- Line 30. “30min” - need a space, correct throughout the text.
- Line 388. “mass range 100-1800Th“ change to Daltons.
- Line 388. “resolution 240 000 et 480 000”. What does "et" mean?
- Line 937. “(Error! Reference source not found.)”
- Table 4. Text revision required. “Pic proportion”, remove parentheses from m/z values, “m/z M-H]–“ correct “m/z [M-H]–“
- Bring the list of references to uniformity in accordance with the requirements of the journal.
Thus, this manuscript requires significant revision. The authors should pay special attention to the proof of the effect of enzymes on increasing the degree of extraction of biologically active compounds.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
After revising the manuscript, the authors managed to significantly improve its quality and eliminate some of the issues. Many aspects have become clearer. I am grateful to the authors for taking my wishes into account. I did not understand only two responses to the comments:
1. "120 μL of enzyme is required per extraction (200 mL)". You are talking about a solution that contains only 12 g of berries. 1000 L will contain 60 kg. 800 euros for 60 kg is quite expensive.
2. "Indeed, this result could be attributed to the enzymatic hydrolysis of pomaces protein matrix, which eventually solubilized them and increased their content at an hydrolyzed form in the aqueous extracts." Could it be that the protein content in the extract increases only because you add an enzyme?
In general, the authors responded to all my comments and took them into account during the revision. The article may be accepted for publication in "Antioxidants".
Author Response
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Author Response File: 
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