Novel Sequential Microwave-Ultrasonic-Assisted Extraction of Phenolic Compounds from Jackfruit (Artocarpus heterophyllus Lam.) Peel Waste Using Choline Chloride-Lactic Acid Deep Eutectic Solvent

Phenolic compounds in jackfruit (Artocarpus heterophyllus Lam.) peel were extracted using novel sequential microwave-ultrasonic-assisted extraction (SMUAE) and a natural deep eutectic solvent (NADES). Choline chloride-lactic acid (ChCl-LA) was an optimal NADES. Optimal conditions of SMUprobeAE (SMUpAE) were 415 W microwave power, 124 s irradiation time, and 7 min ultrasonic time. Total phenolic content (TPC) of a crude extract (CJPE) under the optimum conditions was 53.16 ± 1.23 mg GAE/g DW. SMUbathAE (SMUbAE) could be used instead of SMUpAE to prevent the corrosion of the probe. The different sequences of applying ultrasonic wave and microwave did not differently influence TPC, antioxidant activity of CJPE, and microstructure of peel residues. LC-QTOF-MS/MS profiling of natural products in purified extracts (PJPE) was differently affected by ChCl-LA and 60% EtOH. Chlorogenic acid was the main phenolic compound in PJPE. Glycyrrhetinic acid was found for the first time in ChCl-LA-PJPE. Therefore, SMUbAE integrated with ChCl-LA was an alternative green technique for extraction of phenolic compounds.