Process for the recovery of whey protein having improved solution clarity using polyphosphates

In a process for the recovery of protein having improved solution clarity at acid pH from a proteinaceous aqueous solution containing whey protein in which a medium chain length polyphosphate of the formula:

• ##STR3## wherein X is selected from the group consisting of proteinaceous and alkali metal;
• and Y is alkali metal;
• and N ave. represents an average chain length from about 3 to about 20,000, is admixed with a proteinaceous aqueous solution containing whey protein to form a protein-phosphate complexed solution;
• and the pH of said protein-phosphate complexed solution is adjusted to a range of from about 4.5 to about 2.0 to form a protein-phosphate precipitate, the protein-phosphate precipitate is separated from said mineral solution and dispersed in an aqueous solution having a final pH from about 5.0 to about 12.0 and the protein-phosphate dispersion is contacted with an anionic ion exchange resin to remove phosphate from said dispersion and provide a protein-aqueous effluent;
• the improvement which consists essentially of pretreating said proteinaceous aqueous solution containing whey protein prior to subjecting said proteinaceous aqueous solution containing whey protein to the process outlined in the preamble which pretreatment consists essentially of the steps of:
• a. admixing with said proteinaceous aqueous solution containing whey protein a phosphate selected from the group consisting of tetrasodium pyrophosphate, tetrapotassium pyrophosphate, sodium acid pyrophosphate, potassium acid pyrophosphate, potassium tripolyphosphate, sodium tripolyphosphate, calcium pyrophosphate, magnesium pyrophosphate, ammonium pyrophosphate, or mixtures thereof at a concentration greater than 1.0 gram per liter to thereby form a phosphate complexed solution;
• b. adjusting the pH of said phosphate complexed solution to a neutral range of from about 6.0 to about 8.0 by the addition of a base to a level of base sufficient to form a precipitate and a pretreated proteinaceous aqueous solution containing whey protein;
• c. separating said precipitate from said pretreated proteinaceous aqueous solution containing whey protein to give a separated precipitate and a separated pretreated proteinaceous aqueous solution containing whey protein;
• and
• d. recovering the protein from said pretreated proteinaceous aqueous solution containing whey protein using said process, said protein having improved solution clarity at acid pH.