Lactase enzymes with improved properties at acidic PH

A process for producing a lactose-free or low-lactose acidified milk product, comprising:

• (a) acidifying a milk base to obtain an acidified milk product having a pH of 3.0 to 5.0, and
• (b) before, during, or after step (a), adding a bacterial peptide to the milk base or acidified milk product,
• wherein the bacterial peptide exhibits beta-galactosidase enzyme activity which has an activity optimum at a pH of below pH 6.7 and wherein the bacterial peptide is selected from peptides having the amino acid sequence of any one of SEQ ID NOs. 1, 2, 3 and 14, and
• wherein the acidified milk product has a lower lactose level than an acidified milk product produced by a process where no bacterial peptide is added, but is otherwise identical to the process as claimed.