ORANGE JUICES AND CONCENTRATES STABILIZATION BY A PROTEIC INHIBITOR OF PECTIN METHYLESTERASE

A proteic inhibitor of pectin methylesterase (PME), recently discovered in kiwi, was used to stabilize cloud of orange juice concentrate with "Cut-back," 42-degrees Brix. To concentrated and pasteurized orange juice were added increasing amounts of fresh juice (12-degrees Brix) with PME 0.8 U/mL at the fresh to pasteurized ratios 6.6 to 38%. The PME inhibitor (65% pure), from kiwi, was added at 50 mg/L. After 8 mo at 5-degrees-C samples were compared with controls containing the same amount of fresh juice with PME inhibited by pasteurization. Pasteurized samples were not different from those treated with PME inhibitor. Conversely, where PME was not inhibited, cloud stability decreased with increasing amounts of fresh juice. Use of kiwi PME inhibitor in fruit juice production has potential advantages.