Abstract
Lactase has been identified in many tissues and cells of vegetable or animal origin. Recently, a new purified commercial lactase from Saccharomyces lactis was prepared in Europe. Raw milk was treated with this lactase preparation at various enzyme concentrations and times.
The results obtained are summarized as follows :
1. Lactase activity was 35, 800 ONPG (o-nitrophenyl-β-D-galactopyranoside) unit/g. The released glucose was determined by Farb Test using glucose oxidase and peroxidase.
2. The hydrolysis of lactose during 0-60 min at 37°C, is presented in Fig. 4 for enzyme levels of O.5, 1.0 and 2.0 mg/ml milk. The lactase of 1.0 mg/ml catalyzed 100% lactose hydrolysis in 30 min.
3. As shown in Table 1 and 2, the lactase preparation showed no proteinase activity toward milk protein.
4. The milk treated with lactase became brown in color when heated over 95°C for 10 min.
5. No Appreciable change in flavor quality was recognized of the milk after treatment with lactase. The intensity in sweetness of the product was parallel with the lactase concentration.
