Orange juice is a widely consumed product owing to its high nutritional value and desirable sensory characteristics.The presence of pectin methylesterase (PME) causes loss of cloud stability in cloudy juices (e.g.,citrus and carrot juices).To prevent cloud loss,orange juices are pasteurized at high temperatures ranging from 90 to 95(A) C and for holding times of 15 to 60 s to inactivate PME.Citrus juices contain multiple forms of PME in various concentrations.The populations of thermolabile (85-95%) and thermostable forms of PME (18-5%)in citrus juices were decisive in the different temperature,(A)-time requirements for thermal pasteurization of citrus juices.