Rapid removal of lactose for low-lactose milk by ceramic membranes

The dairy industry requires membranes with narrow-distributed pore size to separate lactose efficiently as the demand for low-lactose milk is increasing. In this study, ceramic membranes were used to remove lactose from skim milk. Ceramic microfiltration membranes were selected for filtration owing to their high permeation flux and high rejection performance for separating lactose and protein. The operating parameters of the microfiltration processes were systematically discussed and optimized, achieving 99% rejection of the proteins with 100% permeation of lactose, and the permeance was as high as 75 L m−2h−1 bar−1. A diafiltration model was proposed to optimize the diafiltration process; moreover, the optimum volume concentration ratio of the pre-concentration process was obtained to minimize the operation time. The diafiltration operation was then optimized to remove lactose from skim milk. The results showed that lactose removal and protein concentration were achieved simultaneously, and low-lactose milk with a lactose concentration of less than 5 g L−1 have been prepared. This study serves as a valuable guide for process design and practical operations in the dairy industry.