Influence of calcium on the properties of micellar casein in goat milk

This study aims to investigate changes in the properties of micellar casein of goat milk caused by the addition of two types of calcium, natural milk calcium and calcium chloride, and decalcification with cation exchange resin. The added calcium partially migrated into the colloidal calcium phosphate, and more calcium added as calcium chloride entered the micelles resulting in a greater decrease in the amount of casein in the goat milk supernatant, the hydration rat and the zeta potential, and a greater increase in turbidity compared with natural milk calcium. The lowest hydration rate of goat casein was observed at the addition of 1.8 mmol/kg of natural milk calcium and at 5.4 mmol/kg for calcium chloride. At the decalcification of 35.8%, the dissociation of casein micelles was basically completed, resulting in a higher hydration rate and the zeta potential, lower turbidity and particle size. Compared with the control group, both calcium addition and removal, decrease the alpha-helix and beta-sheet contents in the casein significantly, and cause a loss of casein micelle properties in the microstructure. This research aims to provide a theoretical basis for the development of calcium-based functional goat dairy products.

Automated summary

This study investigated the changes in micellar casein properties of goat milk following the addition of two types of calcium and decalcification. The results showed that both calcium addition and removal significantly affected the hydration rate, zeta potential, turbidity, and microstructure of casein. This research provides insights into the impact of calcium manipulation on the properties of goat milk casein, which could be valuable for the development of calcium-based functional dairy products.