HPLC AND NMR-STUDY OF THE REDUCTION OF SWEET WHEY PERMEATE

Sweet whey permeate was hydrogenated under high pressure and temperatu re with Raney Ni as a catalyst. Different reaction conditions, such as reaction time, amount of catalyst, and initial hydrogen pressure and temperature, were studied. The reaction mixtures were analyzed by HPLC and NMR. The major whey component, lactose (4-O-beta-D-galactopyranos yl-D-glucose), was converted under these conditions to lactitol (4-O-b eta-D-galactopyranosyl-D-glucitol) to different degrees. Hydrolysis of lactose to galactose and glucose and further reduction was also obser ved over a wide temperature range, whereas isomerization of lactose to lactulose (4-O-beta-D-galactopyranosyl-D-fructose) and subsequent red uction only occurred above 110 degrees C. With reaction time of 4 h, a n initial hydrogen pressure of 1500 psi, 40.5 g of Raney Ni, and a tem perature = 120 degrees C, sweet whey permeate (42%, 340 g) gives lacti tol (85.2%), lactulitol (1.7%), and sorbitol and dulcitol (0.8%) toget her with unreacted fat, protein, and salts (12.3%).