Protein and Polysaccharide Complexes for Alleviating Freeze-Induced Damage in Sour Cream and Yogurt

There has been little research on freezing-induced damage in high-moisture dairy products, specifically sour cream and yogurt. This work aimed to investigate, as a proof-of-concept, if antifreeze additives may prevent quality decrease in high-moisture dairy products due to freeze-induced damage. Whey protein isolate and soy protein isolate were complexed with locust bean gum and lambda carrageenan, in both unhydrolyzed and hydrolyzed forms, and their antifreeze activity was evaluated in a model system as well as in sour cream and yogurt. The biomolecules were also tested individually as controls to determine any synergistic effects. Protein and polysaccharide complexes were found to have ice recrystallization inhibition activity in the model systems by reducing the ice crystal size significantly (35-64%) compared to the negative control at both pH 4.5 and 7.0. However, the complexes failed to prevent freeze-induced damage in the dairy system and all treatments resulted in decreased firmness, cohesiveness, and consistency along with increased graininess, possibly due to the complex interacting with different food components that may have interfered with the antifreeze activity of the tested compounds.