Valorization of seabuckthorn pomace to obtain bioactive carotenoids: An innovative approach of using green extraction techniques (ultrasonic and microwave-assisted extractions) synergized with green solvents (edible oils)

Seabuckthorn pomace (SBT-P) valorization is gaining importance due to the presence of health promoting bioactive compounds. Designed with a green refinery approach, carotenoids (a bioactive pigment) was extracted from SBT-P using green extraction technologies (Ultrasound- and Microwave-assisted extraction, UAE & MAE), synergized with corn and olive oils used as green solvents. Total carotenoid content (TCC) in SBT-P extracts ranged between 26.91 ± 1.96 and 34.35 ± 0.94 mg/100 g in UAE & MAE. Among the different extraction techniques, HPLC data revealed UAE and olive oil extracts to exhibit highest yield of major carotenoids ( lycopene 87.0; β--carotene 18.7 mg/L). The percent inhibition of DPPH free radical ranged between 92.49 ± 1.84 and 94.16 ± 1.06%, whereas total phenolic content ranged from 341.02 ± 10.97 to 405.58 ± 9.58 mg gallic acid equivalent (GAE)/g of extract in UAE and MAE, respectively. Results encourages the use of green technologies for extraction of bioactive carotenoids from SBT-P and are expected to find potential food industrial applications, where natural pigments are in demand. Process for the extraction of carotenoids using different extraction methods- A: conventional extraction (CE) using non-polar solvents (hexane:isopropyl alcohol; 60:40 v/v ); B (i) Ultrasound-assisted extraction (UAE) using corn oil as green solvent; (ii) Ultrasound-assisted extraction (UAE) using olive oil as green solvent; C (i) microwave-assisted extraction (MAE) using corn oil as green solvent; and, (ii) microwave-assisted extraction (MAE) using olive oil as green solvent. • Carotenoids are natural bioactive pigments present in Seabuckthorn pomace. • Green extraction techniques (UAE and MAE) were used to extract carotenoids. • Green solvents (vegetable oils) provides an option to replace organic solvents. • UAE with olive oil showed high carotenoids content and antioxidant activities.