FORMATION OF OLIGOSACCHARIDES FROM WHEY UF-PERMEATE BY ENZYMATIC-HYDROLYSIS - ANALYSIS OF FACTORS

Two-level fractional factorial experiments were designed to study effe cts of enzyme (0.05 and 0.1%) and initial lactose concentrations (L-0: 14 and 23%), pH (5.0 and 7.0) and temperature (35 and 45 degrees C) o n enzymatic formation of oligosaccharides (OS) from whey UF-permeate i n a batch reactor. beta-D-galactosidase from Aspergillus oryzae (A), K luyveromyces lactis (B) and K. fragilis (C) were compared. Hydrolysis with B and C gave comparable yields which were higher than that from A at identical conditions. L-0 did not influence reaction time, but con centration of OS significantly increased by increasing L-0 for all enz ymes. Increasing L-0 reduced the yield after hydrolysis with A and B, but improved the yield for C. L-0 had negligible effect on degree of h ydrolysis (DH) for A and C. However, increasing L-0 significantly lowe red DH for B. Increasing enzyme concentration significantly reduced re action time for A, but it had no effect on that for B and C. DH signif icantly decreased after increasing concentration of A. Consequently, O S and yield were reduced. Applying B and C at higher concentration imp roved DH, OS and yield. Increasing temperature or pH reduced DH, OS an d yield for A, but increased the responses for B and C. (C) 1998 Elsev ier Science Ltd. All rights reserved.