The invention provides zero-
lactose full milk
powder and a preparation method thereof. The preparation method comprises the following steps: adding
raw milk, which is qualified through inspection and has the temperature of 4 DEG C to 8 DEG C, and
lactase, of which the weight is 0.05%-0.1% the total weight of the
raw milk, in a mixing process, carrying out uniform stirring, and carrying out hydrolyzing for 24-48 hours at the temperature of 4 DEG C to 8 DEG C; or performing
pasteurization on the
raw milk, which is qualified through inspection and has the temperature of 4 DEG C to 8 DEG C, for 15 seconds at the temperature of 65 DEG C to 85 DEG C in the mixing process, cooling the temperature of the raw milk to 38 DEG C to 42 DEG C, adding the
lactase, of which the weight is 0.05%-0.1% the total weight of the raw milk, carrying out uniform stirring, and carrying out hydrolyzing for 2-4 hours at the temperature of 38 DEG C to 42 DEG C; and carrying out sampling and detecting again to obtain zero-
lactose full milk when the
hydrolysis rate of the
lactose is more than 98% or more and the residual quantity of the lactose is 0.06% or less. According to the zero-lactose full milk
powder and the preparation method thereof, the lactose is thoroughly hydrolyzed before concentration and
spray drying, the condition that the concentration, the
spray drying and filling are performed after the product reaches a zero-lactose level is guaranteed, the
hydrolysis rate of the lactose can be more than 98%, the zero lactose level is achieved, and the condition that the lactose content required by national standards is 0.5% or below is met.