The invention provides methods for improving at least one physicochemical property of a product comprising casein micelles, the method comprising applying carbon dioxide to an aqueous product comprising casein micelles to reduce the pH of the product; increasing the pH of the product; and collecting the product comprising casein micelles, in which at least some of the casein micelles of the product are modified in structure by one or more of steps a) and b) compared to naturally occurring casein micelles thereby improving at least one physicochemical property of the product comprising casein micelles. The method reduces viscosity and improves mouth feel of reconstituted product, reduces rehydration time for dried product, improves cheese manufacturing by reducing rennetting or clotting time in cheese manufacture or reducing the amount of rennet required in cheese manufacture.