Nucleotide loss caused by alkaline phosphatase renaturation during infant formula production

This study investigates the causes of nucleotide loss during infant formula production. The main cause of the nucleotide loss was nucleotide degradation caused by alkaline phosphatase (ALP). The ALP activity in raw milk was less than 500,000 mU/L. Experimental analysis revealed that ALP was renatured in pasteurized milk, with the addition of phospholipid-rich ingredients (such as the milk fat globule membrane) and minerals added during the mixing process. Pasteurization parameters markedly influenced the degree of ALP renaturation. Furthermore, the thorough homogenization of raw milk prior to pasteurization significantly inhibited ALP reactivation. Validation experiments demonstrated that the risk of nucleotide degradation was significantly reduced by modifying the formula production to involve raw milk homogenization at 18–20 MPa for 1 min prior to pasteurization at 75 °C for 15 s. This study identifies the main sources of ALP in infant formula production and proposes effective measures for reducing nucleotide loss.