Preparation and Properties of Sirups Made by Hydrolysis of Lactose

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Abstract
Clear, nearly colorless sirups were prepared from lactose by hydrolysis with either lactase (~3-galactosidase) or hydrochloric acid, followed by decolor- ization, ion exchange demineralization, and concentration. Crystallization of sugars from the sirups was reduced by decreasing total solids from 66 to 60% and the degree of hydrolysis from 95 to 75%; however, overall stability of sirup with respect to both crystallization and mold growth was optimum at 63 to 66% solids and 75% lactose hydrolysis. Stability was increased further by heating sirups to 70 to 75 C and then hermeti- cally sealing the containers. Viscosities were increased by lowering the degree of hydrolysis as well as by increasing total solids. The hydrolyzed-lactose sirups were as sweet as sucrose sirups above 50% total solids but less sweet than sucrose at lower solids. Although increasing lactose hydrolysis from 75 to 95% increased sweetness, differences were small. The sirups possessed good humectant proper- ties at 40% relative humidity.