Ultrasonic Extraction of Phenolic Compounds from Eggplant Peel and Formulation of Eggplant Peel Extract-Enriched Ice-Cream

Abstract

In this study, ultrasound-assisted extraction (UAE) was used for the extraction of bioactive compounds from eggplant peels (EPP) and conditions were optimized by using response surface methodology (RSM). Methanol concentrations (60%, 70%, and 80%), time (30 min, 45 min, and 60 min), and temperature (30°C, 45°C, and 60°C) were selected as independent extraction parameters, whereas total anthocyanin content (TAC), DPPH inhibition, and total phenolic content (TPC) were response variables. The optimal extraction was at 45°C for 45 min of extraction time with 70% solvent which corresponded to TAC, TPC, and DPPH inhibition values of 7.94 mg/g, 7.03 mg GAE/g, and 94.8%, respectively. The optimized EPP extract was chemically characterized by a Fourier-transform infrared spectrometer (FTIR), high-performance liquid chromatography (HPLC), and a gas chromatography mass spectrometer (GCMS). The optimized extract was further evaluated for antioxidant and anticancer potential. For antioxidant and anticancer potential, the corresponding IC50 values of the EPP extract were 243.2 μg/ml and 1.52–1.99 mg/ml, respectively. Furthermore, the EPP extract significantly inhibited the migratory ability of cancer cells in a dose-dependent manner. Major components identified in the EPP extract were chlorogenic acid (261.76 mg/kg), benzoic acid (184.41 mg/kg), syringic acid (78.48 mg/kg), p-coumaric acid (49.59 mg/kg), cinnamic acid (32.17 mg/kg), quercetin (5.24 mg/kg), sinapic acid (5.14 mg/kg), and gallic acid (4.34 mg/kg). The EPP extract-enriched ice-cream showed high antioxidant potential and consumer acceptability than the blank ice-cream formulation. The EPP extract, due to its antioxidant and anticancer potential, can be used in the formulation of functional food products.