Clarification of the pomegranate juice in a bioreactor packed by pectinase enzymes immobilized on the glass bead activated with polyaldehyde polysaccharides

Abstract

In this study, the glutaraldehyde, polyaldehyde pullulan and polyaldehyde kefiran were applied to immobilize the pectinase on the silanized glass bead and then a packed bed reactor (PBR) was used to continuous clarification process of the pomegranate juice. The results showed that the bioreactor packed with the enzymes immobilized by all three cross-linkers had the best performance at the temperature of 50 °C, a flow rate of 0.5 mL/min and treatment time of 42 min. After the clarification process, the turbidity of the pomegranate juice was significantly decreased from ~70.2 to ~17.4 NTU and the clarity of the samples was increased from ~81.15 to ~96.13%. The findings showed the clarification process had a significant effect on the pomegranate juice properties so that the total titratable acidity, reducing sugar content and lightness parameter were increased while pH, total soluble solids, viscosity, total phenol content and radical scavenging activity of the juice samples was decreased by this process. Finally, it must be stated that the bioreactor packed with polyaldehyde kefiran-immobilized pectinase had the best performance in the clarification of pomegranate juice due to the higher capacity of this cross-linker in the pectinase immobilization.