Screening of lactases suitable for the preparation of low-lactose prebiotic liquid milk and optimisation of their combination

Abstract Lactose intolerance is an important factor restricting the consumption of dairy products. Lactase is used to hydrolyze lactose in milk while generating galactooligosaccharides (GOS), thereby reducing the incidence of lactose intolerance. We used cow milk as raw materials, and selected enzyme preparations with high lactose hydrolysis rate and strong GOS generation ability from 14 commercially available lactase enzymes. The lactose hydrolysis rate is 5.85%-81.38%, and the GOS content is 0.03 g/L- 13.10 g/L. The mixing experiment design determined the two lactase enzymes (E10 and E11) ratio and the optimal enzymatic hydrolysis process of low-lactose prebiotic milk: compound lactases (E10:E11=0.756:0.244) addition 0.11%, 55℃for 5h, lactose hydrolysis rate and GOS content were 98.02% and 19.69g/L, respectively, and the remaining lactose content was about 0.97 g/L.