Effects of Vacuum Ohmic Evaporation on Some Quality Properties of Sour Cherry Juice Concentrates

Sour cherry juice (SJ) having total soluble solid (TSS) content of 19.2 % was concentrated to 65 % TSS by applying vacuum ohmic evaporation (VOE) and vacuum evaporation (VE) methods under constant absolute pressure (25 kPa). Total monomeric anthocyanin content (TMAC) of sour cherry concentrate (65 % TSS) was found in the range of 1561.67-1777.38 mg/L whereas total phenolic content (TPC) varied in the range of 9,071.22-78,347.53 mg/L concentrate. TPC and TMAC values of juice concentrates were affected less from VOE process compared to VE (p < 0.05) while there was no significant difference between the total antioxidant activities of SJ concentrates obtained by both methods (p > 0.05). TMAC and TPC values increased as the voltage gradient applied increased (p < 0.05). VOE process preserved the color properties of juice concentrates better compared to the VE process. It was concluded that VOE method could be an alternative fast evaporation method to obtain high-quality fruit juice concentrates.