Optimization of ultrasound-assisted extraction of (poly)phenolic compounds from blueberry (Vaccinium Myrtillus) leaves

The present paper aims to discover the optimal conditions for ultrasound-assisted extraction (UAE) of (poly)phenolic chemicals from blueberry (Vaccinium Myrtillus) leaves. UAE was performed under the following process conditions: temperature: 25 - 65 ?C, ethanol concentration in the extraction solvent: 30 - 90 vol.%, and solid-to-solvent ratio: 1:15 - 1:45 w/v. Statistical analysis was performed using Design-Expert software, using the Box-Behnken design. The study's Responses were the content of total (poly)phenols, flavonoids, and anthocyanins in the derived extracts. The results indicated that the corresponding response surface models were highly statistically significant (p < 0.0001) and sufficient to describe and predict the content of total (poly)phenols, the content of flavonoids and the content of anthocyanins with R2 of 0.9653, 0.9796 and 0.9720, respectively. The optimal conditions for the extraction are: for total (poly)phenols, 48.4?C, 51.3 vol.% ethanol, and 1:43.8 w/v solid-to-solvent ratio; for flavonoids, 58.5?C, 48.0 vol.% ethanol, and 1:29.8 w/v ratio; and for anthocyanins, 64.2?C, 73.5 vol.% ethanol, and 1:44.7 w/v ratio. The use of UAE enhances extraction yields by increasing the release of bioactive compounds, while the application of the Box-Behnken design allows for precise determination of optimal extraction parameters, thereby achieving maximum yields and efficiency.