Patent ID: 11963542
Assignee: JIANGNAN UNIVERSITY
Field: Food chemistry (Chemistry)
Classification: CPC A | IPC A

Claim 1:
2. The method according to claim 1, wherein a method for preparing the compound casein comprises the following steps:
(1) subjecting animal milk to centrifugation at 20-30° C. for 20-40 minutes to obtain skimmed milk; adding a hydrochloric acid solution until the pH is 4.3-4.9, and conducting centrifugation for 10-20 minutes to obtain a casein precipitate; redissolving the casein precipitate in water, and adding a NaOH solution until the pH is 10-12 to obtain a casein redissolved solution, wherein casein has a mass concentration of 2-3%;
(2) adding calcium chloride to the casein redissolved solution to reach a concentration of 50-70 mM, and conducting centrifugation for 10-20 minutes to obtain a precipitate comprising αs-casein and β-casein and a supernatant comprising κ-casein; adding a hydrochloric acid solution to the supernatant comprising κ-casein until the pH is 3-4, and conducting centrifugation to obtain a precipitate comprising κ-casein; redissolving the precipitate comprising αs-casein and β-casein in water, and adding a NaOH solution until the pH is 6.5-7.5 to make the casein to have a mass concentration of 2-3%; and lowering temperature to 0-8° C., adding a hydrochloric acid solution until the pH is 4.3-4.9, maintaining temperature at 0-8° C. for 4-8 hours, taking a supernatant after centrifugation, heating the supernatant to 30-40° C., and then conducting centrifugation to obtain a precipitate comprising β-casein; and
(3) mixing the precipitate comprising κ-casein with the precipitate comprising β-casein according to a total casein mass ratio of 6:4 to 8:2, conducting dialysis at 0-8° C. for 48-96 hours by using a dialysis membrane with a molecular weight cut-off of 5,000-10,000 Da, adding an ion exchange resin to a dialysate, and after the dialysis is completed, conducting freeze-drying to obtain the compound casein.