Abstract: This invention relates to a process for selectively separating the alpha-lactalbumin from the proteins of whey; the process comprises a heat treatment of the whey previously concentrated to a dry matter content of 10 to 40% by weight, and acidified to a pH of less than 4, preferably from 3 to 3.5, said heat treatment being carried out at a temperature not exceeding 75.degree. C., preferably from 45.degree. to 75.degree. C., for a duration of 15 seconds to 1 hour so as selectively to precipitate the alpha-lactalbumin; this heat treatment is followed by the recovery of the alpha-lactalbumin in the form of a precipitate and possibly of the other lacto-proteins remaining in solution in the residual whey. The process presents the advantage of being simple to carry out and being of low cost.

Abstract: A process for the preparation of decationized, acidified milk having a pH less than or equal to 3.8 wherein milk is contacted with a cation-exchange resin in the acid form at a temperature above 4.degree. C., preferably 8.degree. to 20.degree. C., and in the presence of an excess of milk previously acidified at a pH equal to or less than 3.8, preferably between 2.2 and 2.8, and in which the quantity of ordinary milk introduced is such that the pH of the mixture of acidified and ordinary milk is maintained at a value equal to or less than 3.8, preferably between 2.2 and 2.8.

Abstract: Storage stable, acidulated decationized milk containing the same content of proteins and lactose as ordinary milk, a mineral substance content less than that of ordinary milk and no substances extraneous to the milk and having a pH less than or equal to 3.8 is prepared by placing milk in contact with a cation-exchanging resin in acid form, said milk having a temperature varying between 0.degree. and 4.degree. C., for the time period necessary to lower the pH of the said milk to a value below or equal to 3.8, and separating the decationized milk from the exchanging resin. The decationized milk is used to prepare acidified milks, milk casein, milk acid curds and lactoserum.

Abstract: Acidulated decationized milk containing the same content of proteins and lactose as ordinary milk and having a pH below or equal to 3.8 is prepared by placing milk in contact with a cation-exchanging resin in acid form, said milk having a temperature varying between 0.degree. and 4.degree. C., for the time period necessary to lower the pH of the said milk to a value below or equal to 3.8, and separating the decationized milk from the exchanging resin. The decationized milk is used to prepare acidified milks, milk casein, milk acid curds and lactoserum.