Optimization of Ultrasound-Assisted Extraction on Antioxidative Activity of Malus toringoides Using Response Surface Methodology

Round 1

Reviewer 1 Report

Herein, an efficient optimization protocol for ultrasound-assisted extraction on anti-oxidative activity of Malus toringoides using response surface methodology is reported. This manuscript is concise, well written and presents an interesting piece in this field. I believe this manuscript is well suited in processes after the following revisions.

1)      The references 1 to 3 is apparently in Chinese and not readily accessible to this reviewer. Moreover, from the English abstract it does not seem to be the most appropriate reference; at the very least I would suggest adding one or two other references for this sentence discussions.

2)      I couldn’t find reference number of 25 in the text.

Author Response

Q1:    The references 1 to 3 is apparently in Chinese and not readily accessible to this reviewer. Moreover, from the English abstract it does not seem to be the most appropriate reference; at the very least I would suggest adding one or two other references for this sentence discussions.

Response 1: The references 1 to 3 has been changed.

Q2: I couldn’t find reference number of 25 in the text.

Response 2: The references 25 has been changed.

Reviewer 2 Report

The authors submitted a manuscript on the “Optimization of ultrasound-assisted extraction on antioxidative activity of Malus toringoides using response surface methodology”. 

The topic of this paper is of scientific importance and within the scope of “Processes”. 

An overview of the experimental work and of the most relevant results obtained is presented in the abstract. 

The keywords are appropriate. 

The authors aimed at evaluating the possibility to recover bioactive compounds with cyto-protective activity from Malus toringoides via ultra-sound assisted method.  The objectives of the experimental work are presented in the introduction section. 

A critical description of the state-of-the-art, also supported by other authors contributions, was provided. 

An optimization of UAE process parameters was carried out employing a Box-Behnken experimental design (BBD) coupled with response surface methodology (RSM). HPLC analyses were carried out to identify the major bioactive compounds contained in the Malus toringoides extracts. Furthermore, cyto-protective assay was employed for the validation of the optimized conditions. “

Materials and methods” section accurately describes the statistical, analytical and experimental methods employed. For each factor studied, a subparagraph is dedicated 2.5.1 - 2.5.4. This division might not be necessary and most of the information provided are redundant. It is suggested to revise this section in order to make it clearer and straightforward. 

The results are sorted in subparagraphs and are supported by literature contributions. A critical discussion is provided and the objectives of the experimental work were fulfilled. 

Tables and figures are clear and self-explanatory. In Figure 2, it is suggested to relocate the axes names as they are to attached to the axes. 

Equations should be subsequently numbered and written employing a math editor.

Therefore, equations in lines 210 and 237 should be revised. 

The method proposed by the authors allowed finding optimal liquid-solid ratio, extraction temperature, solvent concentration and extraction time for protection rate against oxidative stress in endothelial cells and phlorizin extraction yield. 

Overall, English language is acceptable.

Author Response

Q1: It is suggested to revise this section in order to make it clearer and straightforward. 

Response 1: The section has been revised.

Q2:In Figure 2, it is suggested to relocate the axes names as they are to attached to the axes. 

Response 2: I am so sorry, this figure is obtained directly by the software（design expert）. This method can get higher resolution images, so no modification has been made to the image

Q3:Equations should be subsequently numbered and written employing a math editor.

Response 3: Equations has been written employing a math editor