Protein characterization of pasteurized milk, cheese whey and their mixtures by using the CEM SprintTM analyzer

Abstract

In this work, the protein analyzer SprintTM was assessed regarding its capacity of predicting addition of whey in milk. This type of practice is relatively common in dairy plants, since whey, as it is a protein component, may be added with little loss of milk protein content. Besides,its incorrect elimination contributes to environmental pollution. Mixtures of milk and whey were prepared in different levels of addition and two methods of milk partition were tested. The results indicated that the concentration of trichloroacetic acid (TCA) from the selected method was not suitable for the present purpose while the chosen method using glacial acetic acid (GAA) has presented a satisfactory separation of the soluble and insoluble milk components. Even though the concentration of whey protein and casein are the essential parameters for determining whey addition in milk, the use of measurements from total protein was important in order to improve the linearity of the method due to the fact that the rates whey protein/total protein and casein/total protein presented the best results concerning fraud prediction capacity. Therefore, as the equipment is a rapid, safe and efficient platform, it can be used as an alternative to be implemented in laboratories of food quality control which perform or plan to perform assays to verify the whey addition in fluid milk.