Acid Hydrolysis of Lactose in Whey Versus Aqueous Solutions

Hydrolysis was over 90% in a 30% (wt/vol) solution of lactose in 2N sulfuric acid at 60 C for 36 h. The brown color that developed during hydrolysis was removed easily with activated carbon. Slight offflavors were removed completely by treatment with calcium hydroxide to about pH 6 followed by activated carbon, yielding a syrup of excellent color and flavor. This process minimized anions and cations in the hydrolyzed syrup. Neutralization with lime and treatment with activated carbon gave a syrup with equisweetness to 20.8% sucrose (g/100 ml). Acid hydrolysis of concentrated whey with sulfuric acid produced a more severe browning reaction and off-flavor. Treatments with calcium hydroxide and activated carbon that were effected in aqueous lactose hydrolysates were ineffective in hydrolyzed whey. Sodium bisulfate inhibited color development during hydrolysis of whey but slowed hydrolysis, affected flavor, and interfered with analytical methods.