Maria A Karlsson
Swedish University of Agricultural Sciences, Sweden
Title: Effect of calcium, citrate and urea on the stability of ultra-high temperature treated milk: A full factorial designed study
Biography
Biography: Maria A Karlsson
Abstract
The composition and properties of raw milk is of significant importance for the stability of the final dairy product, especially in dairy products with long shelf-life such as Ultra-High Temperature (UHT) treated milk. The objective of this study was to, by a full factorial designed study; investigate the effect of elevated levels of calcium, citrate and urea on the stability of UHT milk stored at 4, 20, 30 and 37°C. Stability was evaluated by changes in pH, ethanol stability, heat coagulation time, fat separation, fat adhesion, sediment formation and color. Independent of storage temperature, calcium content had a significant effect on the stability and was strongly correlated to sediment formation. Addition of citrate mainly affected the color of the UHT milk but was also positively correlated to pH and ethanol stability. Urea had little effect on all responses. At all storage temperatures the storage time was closely connected to fat separation and adhesion. Our observations suggest that at different temperatures different mechanisms cause changes in UHT milk during storage. A better understanding for variations in milk composition and changes during storage can improve the shelf-life of UHT milk.