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Effect of thermal treatments on the determination of bovine milk added to ovine or caprine milk

Abstract:

Heat treatment of bovine, caprine and ovine milks at 74°C for 15 or 30 s caused negligible denaturation of whey proteins. After heat treatment at 90°C for 15 or 30 s, denaturation of β-lactoglobulin (β-lg) increased in the order bovine < caprine < ovine milk and denaturation of blood serum albumin (BSA) was in the order caprine < bovine < ovine milk. Mixing of bovine milk with caprine or ovine milk resulted in a 15-20% decrease in thermal stability of bovine β-lg when heated at 90°C for 30 s. Heat treatment at 74°C for 30 s did not affect the quantitative determination of bovine milk in caprine or ovine milk using immunodiffusion or electrophoretic analysis of the whey protein fraction. Heat treatment at 90°C for 30 s allowed the determination of bovine milk by electrophoretic analysis but not by the immunodiffusion method. © 1989.