THE EFECT OF HIGH PRESSURE HOMOGENISATION ON RAW BOVINE MILK PROPERTIES

The treatment on raw bovine milk by high pressure homogenisation (HPH) at 100-300 MPa was performed. The mean diameter of milk fat globules lowered when the homogenisation pressure increased. At 100 MPa of pressure, the size of milk fat globules reduced to a great extent, 6 times smaller (d4,3 = 0,61 μm) than that of unhomogenised milk. Furthermore, homogenisation at 300 MPa resulted in the smallest size of milk fat globules (0,19 μm). For the pressure at 100 and 200 MPa, the use of secondary valve at a pressure equal to 10% of pressure at primary valve decreased significantly the average diameter of fat globules compared to that solely treated by primary valve. Running the milk through homogeniser for 2-3 times of pass (recycling) conducted at 200 MPa (primary valve) and 20 MPa (secondary valve) lowered more significantly fat globule size. The possibility of alkaline phosphatase as an indice of adequate HPH treatment was investigated as well. The enzyme was potential as the indice of adequate HPH treatment since it was entirely inactivated by HPH treatment at an inlet temperature about 24°C.