Effects of industrial-scale, ultrahigh-pressure microfluidizer on microorganisms, active proteins, physical properties, and lipids of cow’s milk

This study explored changes in microorganisms, active substances, physical properties and lipids in response to industrial-grade ultrahigh-pressure microfluidizer (1 t/h) at a 4 °C feed temperature and pressures ranging from 50 to 250 MPa. At 250 MPa pressure, total bacteria, coliforms, and psychrotrophics counts decreased by 4.43, 2.47, and 3.08 log CFU/mL, respectively. The reduction in total bacteria count was significantly higher than that of pasteurized milk (PM20, P < 0.05). Content for immunoglobulin lgG (229.56 ± 4.5 mg/L), lactoperoxidase (3349.74 ± 106.39 U/L), α-lactalbumin (3349.74 ± 106.39 mg/L), β-lactoglobulin (3749.28 ± 29.95 mg/L) were significantly higher than that of PM (P < 0.05). The Turbiscan Stability Index of 250 MPa microfluidized milk is lower than pasteurized milk, whereas its particle sizes (D_3,2 and D_4,3) were similar from those of pasteurized milk (P > 0.05). Lipidomics analysis of pasteurized, and 250 MPa microfluidized milks identified 7 lipids as potential differential markers. This provides a technical basis for replacing traditional, pasteurized milk with industrially microfluidized cow’s milk.