Clarification of Japanese Pear Juice by Inorganic Membranes

Abstract

Inorganic UF membranes (molecular weight cut-off (MWCO); 20000 and 60000-80000 daltons) and two types of dynamic UF membranes (a pre-coat type and a self-rejecting type) were applied to clarify Japanese pear juice. The inoganic UF membrane of MWCO 60000-80000 and the dynamic UF membrane which was pre-coated by depositing Zr colloids 80000 and the dynamic UF membrane which was pre-coated by depositing Zr colloids surface of a ceramic support were suitable for clarification of the juice. They provided not only both high rejection ability of pectin and flux but also the similar sugar and acid contents to the commercial clear juice treated with pectinase. Separation of suspended solids in the sample juice by centrifugation caused a decrease in flux of the permeateof the dynamic UF membrane. During the clarification by the membrane, pectinase treatment ofthe dynamic UF membrane. During the clarification by the membrane, pectinase treatment of the sample juice resulted in little change in the components, but gave higher permeate flux than withoutpectinase treatmen