Abstract
Five lactase preparations (Galantase, Organase, Lactyme, Lamitase and ORG-FG) were compared in terms of enzyme assay and stability. Optimal pH of all the preparations was about 4.5-4.7, when ONPG, lactose and commercial milk were used as substrates. Active pH range of Galantase was 4.0-5.5, while that of the others was 3.5-5.5. Hydrolysis rate of Galantase against lactose was slightly lower than that against ONPG, as compared with the others. Evident difference was observed between Galantase ane Lactyme in pH and thermal stabilities, whereas the other products indicated similar properties to each other.
