Abstract
Consumer focus on health and wellness is drivingthe growth in high-protein dairy beverages. The reviewdiscusses shelf-stable ready-to-drink beverages that areprimarily dominated by sports nutrition and the “betterfor you” beverage categories. Both of these categoriestend to have a “high in protein” claim. Because of theirfunctionality, sensorial attributes, and protein quality,dairy protein ingredients are the ingredients of choiceto meet protein claims. Due to the higher protein contentof the beverages, the functionality of dairy proteiningredients plays a critical role in final product qualityand stability. In the United States, Food and Drug Administrationregulations classify shelf-stable foods intoacid/acidified and low-acid foods. The differentiation isbased on pH and water activity (a_w). In the context ofshelf-stable high-protein dairy beverages, any beveragewith a_w of >0.85 and with a finished equilibrium pH of>4.6 is classified as low acid. Beverages to which acidsor acid foods are added and have a finished equilibriumpH of ≤4.6 and a_w >0.85 are classified as acidified food.Acid foods have a natural pH of ≤4.6. The final pHrequirement of these shelf-stable products will affectthe type of dairy protein used in these applications. Inacidified dairy protein beverages, the go-to ingredientis whey protein. In low-acid beverages, the protein ingredientsof choice are milk protein ingredients (with acasein-to-whey protein ratio of 80:20, as found in typicalbovine milk) and casein-enriched ingredients. Renderingthe product shelf-stable depends on whether theproduct is classified as acidified or low acid. Low-acid,shelf-stable beverages, in general, have 2 manufacturingoptions: retort and UHT processing, followed by hermeticsealing. Pasteurization is the standard processingchoice for shelf-stable acidified beverages, followed byhot fill. Because of differences in pH and heat loadsduring the manufacture of high-protein dairy beverages,the functionality of protein ingredients will playan essential role in determining the final beverage quality.Two of the most important functional properties ofdairy protein ingredients that have a role in producingthese beverages are solubility and heat stability. Thisreview elucidates the physicochemical properties ofdairy protein ingredients for low- and high-acid shelfstabledairy protein applications, analytical techniquesto characterize protein ingredients, beverage processingconditions, and quality defects observed.
NETL
NSTL
Elsevier