Tailoring acid gelation functionality of micellar casein concentrate: Impact of combining microfluidization and calcium chelation on gel firmness and serum binding

Micellar casein concentrate (MCC) is increasingly important as a supplement for milk-derived products, offering broader functionalization possibilities. However, the precise role of casein micelles (CM) in the concentrated state in enhancing fermented milk products remains unclear due to limited knowledge regarding preprocessing impacts on acid gel properties. Understanding the relationship between CM integrity, composition, and particle size in MCC is vital for tailoring their functionality. This study investigated the effects of pre-chelation using trisodium citrate (TSC) addition (0–15 mM) combined with a high-pressure process, i.e. microfluidization (0, 75, 150 MPa) on CM in MCC and derived acid gels. Results unveiled significant changes in CM composition and particle size related to alterations in acid gel characteristics. TSC addition resulted in CM swelling, increased serum binding capacity of the gel, but reduced gel firmness. Subsequent microfluidization significantly reduced particle size and narrowed the size distribution, particularly due to structurally weakened and larger CMs post-TSC treatment. This reduction positively impacted gel firmness by facilitating uniform gel formation. A synergistic effect emerged with TSC treatment up to 5 mM coupled with microfluidization, resulting in serum binding equal to TSC treatment alone while compensating for TSC-induced reduced gel firmness. This study highlights the benefits of targeted CM modification in MCC by combined treatments to tailor gel properties and offers insights into their relationship with CM attributes. This approach offers untapped potential to enable the use of MCC in acidified dairy products by overcoming undesired structural changes in comparison to traditional processing.