Milk protein gels

What is the impact of amino acid mutations in the primary structure of caseins on the composition and functionality of milk and dairy products?

“…The gel strength, curd formation, water holding capacity, and syneresis of milk during acid gelation and rennet coagulation are important functional attributes essential for the end-product functionality for a variety of products, including yogurt and cheese ( Lucey, 2020 ). In the last decade, several studies showed that β-casein genetic variants in milk can be correlated to milk gelation and coagulation properties ( Bisutti et al, 2022 ; Gustavsson et al, 2014 ; NguyenSchwendel et al, 2018 ; Poulsen et al, 2013 ; Poulsen et al, 2017 ; Vigolo, Franzoi, Penasa and De Marchi, 2022a ).…”

“…On the contrary, Wang et al (2022) concluded that acidified and fermented A2/A2 milk had smoother microstructure, better texture, and rheological properties than the fermented A1/A2 milk. Nevertheless, the authors neither stated the amount of proteins (ratio of caseins and whey proteins) in both milks, nor they declared the content of milk's minerals, both of which are crucial for firmness and structure of milk gels ( Lucey, 2020 ).…”

“…Upon the gel creation, the system relies on re-arrangement of the bonds among individual caseins creating the original casein micelles ( Lucey, 2020 ). Therefore, an improved gel firmness is rather associated with a higher number of such bonds ( Lucey, 2002 ; Lucey et al, 2000 ; Van Vliet, Van Dijk, Zoon and Walstra, 1991 ).…”

“…The reason behind this phenomena can be related to the difference in κ-casein contents in A1/A1, A1/A2, and A2/A2 gel types ( Daniloski et al, 2022d ; NguyenSchwendel et al, 2018 ; Poulsen et al, 2013 ). On that account, lower amount of κ-casein indeed translates into fewer interactions, at least at the surface of the casein micelles during coagulation ( Lucey, 2020 ); milks comprised of β-casein A1 contained more κ-casein, that theoretically led to a much larger number of particles and higher surface area ( Daniloski et al, 2022d ; NguyenSchwendel et al, 2018 ). Therefore, in A2/A2 milk a lower number of interactions were created, compared to A1/A1 and A1/A2 milks and therefore a softer gel ( Daniloski et al, 2022d ).…”

Use of Electro-Activated Whey as Ingredient in Fermented Milk Production: Proof of the Concept of the Technological Feasibility

“…Solutions to improve the textural properties and appearance of fermented dairy products include the increase of total dry matter content, heat denaturation of whey proteins to improve the water holding capacity of the proteins matrix, high pressure homogenization, use of microbial enzymes as well as special starter cultures producing exopolysaccharides with high texturizing capacity, and addition of hydrophilic hydrocolloids. , In many fermented dairy products, the addition of hydrocolloids or thickening agents such as gelatin, carrageenan, and starch is prevalent; however, they do not correspond to the all-dairy composition of the final product. Moreover, some of them may meet restrictions as halal, kosher, or organic composition of the product .…”