Today in 1975, US Patent 3888839 A was issued, an invention of Jon Albert Newell, Robert Dudley Seeley, and Ernest Aleck Robbins, assigned to Anheuser Busch, for their “Isolated Yeast Protein Product with Intact RNA and a Process for Making Same.” There’s no Abstract, although in the description it states that “We have discovered a process for obtaining a protein isolate from yeast cells. This process makes use of a neutral or slightly alkaline extraction of disintegrated cells to avoid the deleterious effect on nutritional quality and flavor.”
SUMMARY OF THE INVENTION Our process is comprised of the following steps: production of yeast cells, rupture of the cells, separation of the insoluble cell wall fragments from the soluble cytoplasmic fraction, treatment of the soluble fraction with alkali, recovery of the protein by precipitation and centrifugation, vacuum concentration, and drying. The substantially cell free isolated protein product contains about 40% of the solids, -65% of the protein, 60-65% of the nucleic acid, 64-68% of the lipid and less than 5% of the carbohydrate that was present in the yeast cell. The isolated protein product has the composition (dsb) of 65-85% crude protein, 9-14% nucleic acid, 2-8% ash, 9-14% lipid, and 2-10% carbohydrate, while including less than 1% crude fiber.