The performance of a 0.2 km ceramic membrane for clarification of depectinized apple juice was studied. The results showed that the flux was higher at high feed velocities (14.6 m/set) and high temperatures (5o"C), and the transmembrane pressure was a positive factor only at high temperatures. The juice flux at optimal conditions was between 4&J-500'kg/hr.m*. Filtration of juice with pectin resulted in flux decreases of 40-50% compared to deoectinized juice. Periodic backflushing during processing' at optimal conditions, i.e., high temperature, high feed velocity and low pressure, did not significantly increase the juice flux.

Frozen apple juice concentrate was prepared using conventional procedures. Response surface methodology was used to statistically model the results. A regression equation was derived as a function of "Brix and pectin concentration. The results of this investigation indicated that pectin contributed to the freezing point depression of apple juice concentrate, the effect of which was greater with increasing concentration. The untreated apple juice concentrate (with pectin intact) had a lower freezing point compared to the depectinized juice. The freezing point of apple juice concentrate decreased as the apples ripened as would be expected due to an increase in soluble pectin.