Method of producing sterile and concentrated juices with improved flavor and reduced acid

Abstract

Ultrafiltration is employed to preferentially pass an ultrafiltration (UF) permeate containing flavor and aroma components while retaining spoilage microorganisms in a UF retentate. The UF retentate is then treated to inactivate a sufficient number of spoilage microorganisms to inhibit spoilage of the juice under storage conditions. A UF permeate containing flavor and aroma components is then recombined with the UF retentate to provide a food juice suitable for storage while avoiding the loss or alteration of the desirable flavor and aroma components of fresh juice encountered in conventional juice processing. If desired, spoilage enzymes can be retained in the UF retentate and inactivated to inhibit deterioration of desirable juice qualities. Further, the UF permeate can be further treated by reverse osmosis to concentrate flavor and aroma components in an RO retentate. If desired, the acid content of juice can be reduced by passing a portion of the RO retentate or UF permeate through an ion-exchange column.