One-Pot Synthesis of Lactose Derivatives from Whey Permeate

The simultaneous production of lactulose (LAU), lactobionic acid (LBA), and organic acids from sweet and acid whey permeate (SWP and AWP) via catalytic synthesis (5% Ru/C) was studied in a continuous stirred-tank reactor. At selected conditions (60 °C, 60 bar, and 600 rpm), a maximum conversion of lactose (37 and 34%) was obtained after 90 min for SWP and AWP, respectively. The highest yield calculated with respect to the initial concentration of lactose for LAU was 22.98 ± 0.81 and 15.29 ± 0.81% after only 30 min for SWP, and AWP, respectively. For LBA, a maximum yield was found in SWP (5.23%) after 210 min, while about 2.2% was found in AWP. Six major organic acids (gluconic, pyruvic, lactic, formic, acetic, and citric acid) were quantified during the one-pot synthesis of lactose.