Abstract
Ice cream and frozen desserts fortified with protein often have undesirable physical and textural properties despite their increased nutritional value, and are susceptible to shrinkage during storage. The effects of dairy protein structure on structural and physical properties of the mix and frozen product were identified by studying frozen dessert mixes formulated to contain 6% milk protein concentrate, sodium caseinate, or whey protein isolate. The addition of 0.15% mono- and diglycerides decreased the mean ice crystal and air cell size in all frozen desserts and increased the degree of fat destabilization in frozen desserts made with milk protein concentrate and whey protein isolate, providing resistance to collapse during melting. The interfacial activity of serum proteins, casein micelles, nonmicellar casein, and mono- and diglycerides was essential to sequential formation and stabilization of structure, especially with regard to the emulsified fat globule membrane composition and formation of destabilized fat network during freezing. The correlation between rate of drip-through during melting and degree of fat destabilization was independent of protein source, demonstrating how mix ingredient functionality influenced the co-development of ice, air, fat, and serum phase structures in the frozen dessert, which ultimately governed the physical properties of the frozen dessert. PRACTICAL APPLICATIONS: With the continued interest in high-protein products, this work demonstrates the potential for selectively choosing type of protein to enhance physicochemical and microstructural properties of ice cream and frozen dairy desserts.