Screening the effect of different extraction methods (ultrasound-assisted extraction and solid–liquid extraction) on the recovery of glycoalkaloids from potato peels: Optimisation of the extraction conditions using chemometric tools

Abstract

Solid–liquid extraction (SLE) (extraction time (5.5–69.5min) and temperature (25.5–89.5°C)) and ultrasound-assisted extraction (UAE) (extraction time (5–25min) and temperature (25–85°C), and amplitude (50–100%)) were investigated and optimised as a means to recover steroidal alkaloids from potato peel. Optimisation for the recovery of α-solanine, α-chaconine, and total glycoalkaloid content (TGA) from potato peels was performed using a central composite design (CCD) and Box–Behnken design for SLE and UAE, respectively. For SLE, the recovery of glycoalkaloids increased with increasing temperature, while time had no significant effect (at p<0.05). The optimum conditions for the recovery of α-solanine, α-chaconine, and TGA during SLE were found to be an extraction time of 76.6min and extraction temperature of 83.5°C. For UAE, the recovery of glycoalkaloids also increased with increasing extraction temperature (at p<0.05). However, amplitude and extraction time did not significantly affect the recovery of the targeted metabolites (at p<0.05). The optimum conditions for the recovery of α-solanine, α-chaconine, and TGA during UAE were found to be an extraction time of 20min, temperature of 85°C, and amplitude of 100%. SLE resulted in significantly higher recoveries of glycoalkaloids than UAE with both models accurately predicting extraction yields as confirmed by experiments conducted under optimum conditions.