Changes in orange juice characteristics due to homogenization and centrifugation

Two common operations in citrus plants are homogenization and centrifugation. By homogenization, the size of suspended particles decreases and, therefore, cloudiness and color intensity increase. By centrifugation, the total pulp content is controlled. The objective of this paper is to quantify the effect of these operations (and of their combination) on color, cloudiness, suspended pulp, particle size of cloud components, and pectin methylesterase (PME) activity, either in the whole juice or in the two fractions obtained by centrifugation. Results showed that homogenization at 20 MPa give low-pulp well-colored orange juices, although additional treatments are necessary to reduce residual PME activity. Juices with similar physical characteristics were obtained either when the whole juice was homogenized, or when homogenization was applied only to the pulpy fraction obtained by centrifugation and then blending this fraction back with the low pulp fraction.