Operazioni integrate a membrana nella trasformazione del succo di kiwi

An integrated membrane process, operating at low temperatures, for the clarification and concentration of the kiwifruit juice was developed. The process is based on a preliminary ultrafiltration (UF) treatment for the removal of suspended solids, with a consequent reduction of the juice viscosity and torbidity. Total acidity and pH, as well as total phenolics and organic acids content were not influenced by the UF treatment. The clarified juice was then dehydrated by osmotic distillation (OD), producing a concentrated juice with a total soluble solids (TSS) content of 65°Brix. During the OD process the TAA and the ascorbic acid content of the concentrated juice were maintained constant independently of the achieved concentration degree.