Acidulated milk with low mineral content - made by treating fresh milk with cation exchange resin, useful for addn. to milk to form casein coagulate

摘要

Acidulated decationised milk is claimed having the same protein and lactose content as ordinary milk, but with a very low mineral content of less than 4 g/l, a Ca/P ratio of less than 0.5 and a pH of less than or equal to 3.8. The milk is obtd. e.g. by treating milk at 0-4 deg.C with a cation exchange resin in acid form until the pH of the milk is less than or equal to 3.8, esp. 1.5-3.5. Pref. ion exchange resin is a polystyrene resin carrying sulphonic acid gps., with a gel or macroporous structure. The treatment is carried out e.g. by percolation or in counterflow using a vol. ratio of (pref. skimmed) milk to exchange resin of 5:1 to 15:1. The decationised milk is esp. useful in the prodn. of casein and lactoserum by mixing ordinary milk with an amt. of the decationised milk sufficient to lower the pH of the mixt. to around the isoelectric point of milk casein (4.4-4.6) and heating to 10-60 deg.C to coagulate the casein in the mixt., followed by recovery of the casein and the lactoserum. Process allows rapid prodn. of cheese or curds from milk and avoids drawbacks associated with prodn. of casein by acidulation of milk with exchange resins using prior art processes.