Influence of depectinization in the ultrafiltration of West Indian cherry (Malpighia glabra L.) and pineapple (Ananas comosus (L.) Meer) juices

Abstract

Clarification of West Indian cherry (Malpighia glabra) and pineapple (Ananas comosus) juices by cross-flow ultrafiltration using polysulfone hollow fibre and ceramic tubular membranes, with nominal molecular weight cut-off values of 100 kD and average pore diameter of 0.01 microm was studied. The influence of enzymatic treatment using enzyme concentrations of 20, 100 and 300 mg/litre, time of 90 minutes and temperature of 40degreesC for depectinization was verified. The juices were then clarified in a laboratory-scale filtration unit, with an effective filtration area of 0.12 m2 for the polysulfone hollow fibre membrane and 0.005 m2 for the ceramic tubular membranes. The influence of enzymatic treatment on viscosity, turbidity and total pectin of the juice, before ultrafiltration, is reported. Membrane performance was evaluated in terms of flow rate and clarity of the permeate. The permeate flow rate of depectinized pineapple juice was higher (30-60%) for both membranes. Depectinized West Indian cherry juice presented a lower permeate flow rate for the polysulfone hollow fibre membrane. The increase in permeate flow rate, with the use of 300 and 100 mg/litre enzyme concentration was not significant. Thus, it is economically advantageous to ultrafilter depectinized juice treated with an enzyme concentration of 200 mg/litre.