Regulation of casein micelles dissociation by sodium tripolyphosphate to improve gel properties as stabilizers and protein fortifier for high-protein yogurt

STPP induces casein micelle dissociation by chelating calcium. • STPP enhanced buffering capacity and delayed acidification during fermentation. • STPP improved water holding capacity and gel strength of high-protein yogurt. • Promoted elastic gel network, enabling a clean-label protein-based stabilizer. High protein yogurt has a strong market competitiveness, but the gel structure of yogurt with higher protein content is worse than the ordinary. In this study, the effects of micellar casein dissociation induced by different concentrations of sodium tripolyphosphate (STPP) on the gel properties of casein were investigated. Increasing STPP concentration significantly reduced the turbidity of Micellar Casein Concentrate (MCC) suspensions while markedly enhancing their solubility and surface negative charge. UV–visible absorbance indicated dissociation of casein micelles upon STPP treatment. When incorporated into yogurt, samples treated with different STPP concentrations exhibited concentration-dependent acidification delay during fermentation. Moreover, STPP addition significantly improved water-holding capacity, gel strength, and textural properties of yogurt. Dynamic rheological measurements revealed that both the storage modulus (G′) and loss modulus (G″) of the STPP-treated groups were significantly higher than those of the control, confirming the formation of stronger and more elastic gel networks following STPP treatment. STPP effectively modulated the structure and functionality of casein micelles, leading to improved yogurt gel properties. These findings provide new insights into the modulation of casein micelle functionality and support the development of novel stabilizing strategies for yogurt products.