Methods for Extracting Milk Protein from Expired or Spoiled Milk

A method for extracting protein from milk comprising the steps of:

• mixing the milk with an acid solution, thereby forming a milk solution;
• sterilizing, deodorizing and dissociating the protein;
• filtering the milk solution to remove bacteria and impurities to obtain a stock solution;
• subjecting the stock solution to fine filtration to remove hyphae, denatured proteins and solid jelly;
• transferring the filtered stock solution to a container;
• adding a sodium hydroxide solution to the filtered stock solution until a pH of between 7 and 9 is achieved;
• adding an activator to the filtered stock solution for protein activation;
• adding a dilute acid solution dropwise to the filtered stock solution, thereby causing the dissociated protein to self-assemble, complex and salt out to obtain a regenerated milk protein;
• defatting the regenerated milk protein with a degreasing agent;
• washing and filtering the milk protein to obtain a skim milk protein;
• and
• drying the skim milk protein.