This invention provides a method for preparing low-fat
lactose-free milk, belonging to the field of dairy product technology. Based on
raw milk, the method involves centrifuging to obtain low-fat milk, adding
lactase (produced through aerobic
fermentation using
Aspergillus oryzae CICC 40228 and
Kluyveromyces lactis BNCC 186193 and then immobilizing it) for
enzymatic hydrolysis. The milk is then subjected to vacuum degassing, VTIS instantaneous sterilization, and two-stage homogenization to obtain low-fat
lactose-free milk. The immobilized
lactase prepared by the combined microbial
fermentation has
high activity and good compatibility, enabling deep
lactose hydrolysis without introducing undesirable flavors. Vacuum degassing removes gases and
trace amounts of off-flavors from the milk base and prevents oxidative denaturation. VTIS instantaneous sterilization achieves commercial
sterility while maximizing the preservation of milk nutrients and natural
flavor. Two-stage homogenization optimizes the low-fat milk colloidal dispersion
system through the synergistic effect of high-pressure crushing and low-
pressure stabilization, solving the problems of fat floating and
protein precipitation.