Ethanol Content In Solvent Research Articles

Optimization of ultrasound-assisted extraction (UAE) of (poly)phenolic compounds from blueberry (Vaccinium myrtillus) leaves using full-factorial design

Abstract In this work, the influence of process parameters (temperature: 25 - 65 °C, ethanol content in the extraction solvent: 30 - 90 vol.%, and solid-to-solvent ratio: 1:15 - 1:45 w/v) on the process of ultrasound-assisted extraction (UAE) of (poly)phenols from blueberry leaves (Vaccinium myrtillus) was investigated. Statistical analysis was performed using the MINITAB 21 software, with the application of three-level full factorial designs. The Responses in the study are the content of total (poly)phenols, flavonoids and anthocyanins in the obtained extracts. The extraction of blueberry leaf was significantly (p < 0.05) impacted by process variables. The R2, Adjusted R2, and Predicted R2 values in the study are high, showing a significant relationship between the independent variables and the Response. The optimal temperature for all three Responses is 65 °C, the optimal solid-to-solvent ratio for total (poly)phenols and anthocyanins is 1:45 w/v and for flavonoids is 28.03 w/v, while the optimal ethanol content in the solvent for total (poly)phenols, flavonoids and anthocyanins is 51.21 vol.%, 50.61 vol.% and 83.33 vol.%, respectively.

Ultrasonic Extraction and Separation of Taxanes from Taxus cuspidata Optimized by Response Surface Methodology

Taxanes are natural compounds with strong antitumor activity. In this study, we first extracted taxanes from the needles of Taxus cuspidata using ultrasonic (US) extraction, and then assessed the effects of different extraction conditions on the yields of eight target compounds. Response surface methodology (RSM) was further used to optimize the extraction conditions: when the liquid-to-solid ratio was 20.88 times, ultrasonic power was 140.00 W, ultrasonic time was 47.63 min, and ethanol content in solvent was 83.50%, taxane yields reached the maximum value of 354.28 μg/g. Under these conditions, the actual extraction rate of taxanes from the needles was 342.27 μg/g. The scanning electron microscopy (SEM) results indicated that the morphology of the needles, suspension cells, and callus of Taxus cuspidata extracted by ultrasonic wave had changed, the pores of the sections of the needles extracted by ultrasonic wave had become relatively loose, and the pore diameter had obviously increased. The callus and overall structure of the suspension cells extracted by ultrasonic wave were destroyed, forming cell fragments. The components of Taxus cuspidata are complex; the high-performance liquid chromatography (HPLC) method established in this paper is suitable for the rapid and effective separation of taxanes in Taxus cuspidata. We systematically and comprehensively compared the yields of taxanes in needles, callus, and suspension cells of Taxus cuspidata, and the taxane yields were increased by the suspension cell culture.

Diameter regulated ZnO nanorod synthesis and its application in gas sensor optimization

ZnO nanorods with a range of diameter were synthesized by a one-step solvothermal method via adjusting ethanol content in solvents. Material characterization has included XRD, SEM, PL and XPS. It was found that diameter of the ZnO nanorods can be regulated by adjusting ethanol content in solvent. When the ethanol content was increased from 10% to 50%, average diameter of the resultant ZnO nanorods decreased from 360 to 220 nm monotonically. It is also found that ZnO nanorods (a20) prepared with 20% ethanol in solvent has the best crystallinity as revealed in XRD analysis. PL and XPS analyses suggest that the ZnO nanorods are Zn-rich – a beneficial factor to gas sensing response. Gas sensor fabricated using a20 gave the best alcohol vapor response.

Effect of pH and ethanol content of solvent on rheology of zein solutions

Zein, a corn protein, is a mixture of the polypeptides α-, γ-, β-, and δ-zein. α-Zein and γ-zein comprise 70–85% and 10–20% of total zein mass, respectively. Both peptides have similar amino acid composition, except γ-zein is rich in cysteine. The presence of cysteine has been associated with gelation of zein solutions. A common solvent for zein is aqueous ethanol. Preliminary results suggested that pH and ethanol content affect the rheology of zein solutions. Our objective was to investigate the effect of ethanol content (65–90%) and pH of the solvent (2, 6, and 12) on rheological properties of zein solutions (20% w/w) containing γ-zein. Steady shear tests and oscillatory time sweeps were performed to determine flow behavior and gelation time of zein solutions. Results indicated that α-zein solutions were nearly Newtonian while those containing γ-zein showed shear thinning behavior. At high pH, γ-zein increased the consistency index (K) and shortened gelation time. Results were attributed to the cysteine in γ-zein. High pH promoted formation of disulfide bonds leading to higher K values and shorter gelation times. Results of this work are expected to be useful in the design of zein extraction processes and the development of new zein applications.