Effects of pasteurization and ultra-high temperature processes on proximate composition and fatty acid profile in bovine milk

Abstract

The aim of this work was to evaluate the effects of pasteurization and ultra-high temperature processes on proximate and physicochemical composition, microbiological parameters and fatty acid profile in bovine milk. Raw, pasteurized and sterilized milks were collected at a dairy factory in the state of Rio Grande do Sul, Brazil. The samples were submitted to determination of moisture, protein, total fat, lactose, total solids, free-fat dry extract, urea, calcium, phosphorus, pH, acidity, density, fatty acid profile, somatic cell count and total bacterial count. Pasteurized and ultra-high temperature milks kept protein and lactose content similar to raw milk. Pasteurization and sterilization altered the composition of the milk slightly, decreasing total fat and total solids and increasing urea. These processes changed essentiality short-chain fatty acids (4:0, 6:0 and 8:0). High proportions of palmitic acid (18:0), oleic acid (18:1 n-9), stearic acid (18:0) and myristic acid (14:0) were found in all milks analyzed. The absence of large significant modifications on milk composition and fatty acid profile indicates that the processes could be applied without altering the nutritional value of the milk.