Prior denaturation and aggregation of whey proteins: is this a useful strategy for increasing the content of these proteins in UHT high-protein dairy beverages?

UHT treatments applied to dairy products have been associated with modifications on the proteins' structure that may trigger the occurrence of fouling, sedimentation and/or gelation. These issues are particularly relevant regarding formulated whey protein-rich dairy beverages. In this context, this study aimed to evaluate the impact of a two steps preheating treatment coupled with homogenization (pretreatment) prior to UHT treatment to allow an increase of whey protein concentration in UHT high-protein dairy beverage. The pretreatment was applied to 10% w/w protein formulated beverages displaying casein (CN) to whey protein (WP) ratios of 40:60 and 30:70. The pretreated beverages were compared with non-pretreated beverage containing 50CN:50WP ratio. The applied pretreatment induced the denaturation of around 97.8-99.4% of WP. After UHT treatment, despite the higher concentration of WP, pretreated beverages displayed similar particle size distribution and equivalent or lower sedimentation level than the non-pretreated samples. The present study reveals the potential of the pretreatment for allowing the increase of WP content in UHT treated high-protein beverages. The results reinforce the rationalization of process development as a useful strategy for producing stable high-protein products.