The protein composition characteristics in the formation of ultra pasteurized milk shelf life

Assessment of the shelf life of food products is a key aspect of modern production, in connection with which it became necessary to use accelerated methods for assessing the shelf life of dairy products, especially products of a functional orientation. The purpose of the work was to determine the estimated characteristics of the protein composition of UHT milk during storage. UHT milk (UH-milk) with a mass fraction of 3.2 % fat was used as the objects of research. According to the results of research, it was noted that all the constituent components of proteins are subject to changes: milk, including non-protein nitrogen (NBA), whey proteins (SB) and proteins of the casein fraction, which is due to the process of hydrolysis, a change in the structure of the protein. With long-term storage of UP-milk after 9 months, the content of SB increased by more than 10 %, the content of casein proteins decreased by more than 10 %, while the content of NBA increased by 30 %. The fractional composition of the protein was changed, the content of β-lactoglobulin decreased by an average of 20 % in relation to the control sample. Significant changes in β- and κ-casein are observed after 3 months of storage. After 9 months of storage, the content of β-casein decreased by 20 %, while the content of κ-casein increased by more than 30 %. The data obtained allow us to conclude that irreversible changes in the protein composition in UP-milk occur during storage which affects the quality of the product. The estimated characteristics of UP-milk during storage are expanded. The need to determine the content of SB and NBA, the fractional composition of casein proteins, namely the content of β- and κ-casein is established, which will make it possible to predict the storage capacity of the product in the future.