Optimization of Sequential Microwave-Ultrasound-Assisted Extraction for Maximum Recovery of Quercetin and Total Flavonoids from Red Onion (Allium cepa L.) Skin Wastes

• Published in: arXiv.org
• Main Authors: Zeinab Jabbari Velisdeh, Najafpour, Ghasem D, Mohammadi, Maedeh, Poureini, Fatemeh
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 13.04.2021
• Subjects: Ethanol; Flavonoids; Food processing; Onions; Optimization; Response surface methodology; Skin; Ultrasonic imaging; Ultrasound; Wastes
• ISSN: 2331-8422

This study aimed to optimize the extraction conditions in order to maximize the recovery yields of quercetin and total flavonoids from red onion skin wastes using sequential microwave-ultrasound-assisted extraction. Five effective factors on quercetin extraction yield were investigated using response surface methodology. The method was successfully performed under optimal conditions of 60 s microwave irradiation followed by 15 min sonication at 70 {\deg}C, 70% ethanol with solvent to solid ratio of 30 mL/g. Based on the optimization results, ultrasound temperature was found to be a highly significant and influential factor for the recovery. The maximum recovery yields of quercetin and total flavonoids from red onion skin were estimated to be 10.32 and 12.52%, respectively. The predicted values for quercetin (10.05%) and total flavonoids (12.72%) were very close to the experimental results. The recovery yields obtained from different extraction methods were as follows: ultrasound-microwave-assisted extraction (7.66% quercetin and 10.18% total flavonoids), ultrasound-assisted extraction (5.36% quercetin and 8.34% total flavonoids), and microwave-assisted extraction (5.03% quercetin and 7.91 % total flavonoids). The validity of the projected model was examined by the obtained experimental data; in which, the validated model was suitable for the recovery of the valuable products from onion skin wastes for further scale-up in the food processes.