Extraction of anthocyanin from Black plum (Syzygium cumini Skeels) using pulsed-electric field assisted

Abstract

The objective of this research was to investigate the extraction of anthocyanin from black plum (Syzygium cumini Skeels) using pulsed electric field which was supplied from parallel batch electrode chamber made from polyamide. Black plum samples were treated with 5, 10, 20 and 30 kV of pulsed electric field (0.7, 1.3, 2.7 and 4.0 kV/cm of electrical strength, respectively) with different frequencies 10, 20 and 30 kHz. Temperature, electrodes distance and power supply were controlled. Water was used as a solvent in the experiments because it was the solvent used in black plum juice production. The results showed that increasing in the electric field strength and frequencies increased the extraction yield of anthocyanin (cyanidin-3-glucoside) and two-folds decreased time to attained the equilibrium significantly (p<0.05) compared with the traditional maceration method. The optimum conditions that yielded the highest anthocyanin concentration were 30 kV voltage, 4.0 kV/cm electric field strength, 30 kHz frequency and 60 minutes extraction time. In these conditions, anthocyanin concentration was 1.14±0.020 mg/g fresh weight and 32.56% higher than that of traditional maceration. It also gave the maximum electrical conductivity disintegration index (Z) value (0.84±0.021). In addition, the concentration of cyanidin-3-glucoside, malvidin-3-glucoside and pelargonidin-3-glucoside, total phenolic contents and DPPH radical scavenging activities in whole fruits were significantly higher than peels (p<0.05). In conclusion, pulsed electric field-assisted extraction of anthocyanin was possible suggested method for black plum juice processing in the future.