Effect of UHT treatment on the composition and oxidation of lipids in the fat phase of dairy products during storage

The diary industry uses various technologies to extend the shelf life of milk products. However, longer shelf life of foodstuffs frequently results in their lower nutritional levels. Milk fat contains more than 400 fatty acids, which are involved in the development of the human nervous system and other biochemical processes. Similar to other fats, milk fat is susceptible to oxidative damage during storage. This affects such basic components of milk fat as fatty acids and triacylglycerides. At present, milk is used for the production of functional foods for infants and children. The shelf life of such products is increased by heat treatment.Temperature regimes of milk treatment are aimed at impeding microbial spoilage. However, high-temperature processing may accelerate the process of triglyceride oxidation, which will decrease functional properties of dairy products for infants during storage. Therefore, it is important to study the effect of shelf life on the oxidation of milk lipids in dairy products, including those enriched with essential substances.This article examines the effect of UHT treatment and storage on milk lipids by evaluating the fatty acid and triacylglyceride composition, as well as such indicators of oxidative fat spoilage, as peroxide and anisidine values, and the content of free fatty acids. It is shown that the composition of milk fat triglycerides undergoes changes following 60 days of storage. An evaluation of the resulting auto-oxidation products revealed a relationship between the composition of milk fat triglycerides and general indicators characterizing oxidative damage.