Clarification of apple, grape and pear juices by co-immobilized amylase, pectinase and cellulase

Abstract

In this study, the use of co-immobilized amylase, pectinase and cellulase enzymes for clarification of apple, grape and pear juices were investigated. Four different co-immobilization method was applied and the highest activity was observed for co-immobilized enzymes onto silica gel. The effect of the enzyme units used in the co-immobilization, reaction temperature and time on turbidity and reducing sugar concentration were optimized by Response Surface Methodology (RSM) via Design Expert Software 8.0.7.1. applying 3-factor Box-Behnken design. Co-immobilized samples were reacted with the substrate solution in batch type and feedback packed bed column reactors and according to turbidity and reducing sugar concentration values, batch reactor efficiency was found to be higher. Finally, freshly squeezed apple, pear and grape juices were interacted with co-immobilized enzymes in the batch reactor system, and turbidity and reducing sugar concentrations were monitored over time. Changes were also observed in antioxidant activities depending on the enzyme treatment.