Single-stage ultrasound-assisted process to extract and convert α-solanine and α-chaconine from potato peels into β-solanine and β-chaconine

Potato peels are rich in alpha-solanine and alpha-chaconine, which are glycoalkaloids with known pharmacological activity but that have high cytotoxicity. Their aglycones (beta-solanine and beta-chaconine) have the same pharmacological activity but with a much lower cytotoxicity. In this work, we applied ultrasound technology to extract alpha-solanine and alpha-chaconine from potato peel and at the same time convert these molecules into beta-solanine and beta-chaconine, in a single-stage process without resorting to organic solvents. The extraction was studied varying ultrasonic power density (20, 35, and 50 W/L) and processing time (5, 10, 20, and 40 min) using an ultrasonic bath operating at 25 kHz. The chemical analysis was done by UHPLC-qTOF-MS and the results were evaluated by HCA, PCA, and PLS-DA chemometric analysis. The analysis of the single-stage procedure pointed to the viability of concomitant extraction and chemical conversion of alpha-solanine and alpha-chaconine into beta-solanine and beta-chaconine when operating at an ultrasonic power density of 35 and 50 W/L and subjecting the potato peel power to 20 and 40 min of ultrasound.