Chemical methods for the reduction of the purine content of baker's yeast, a form of single‐cell protein

Abstract Chemical procedures, suggested by methods formerly used to prepare yeast RNA, or in the analysis of nucleic acids, were applied to the preparation of nucleic acid‐reduced baker's yeast. Water at 80–100°C extracted nucleotides but no nucleic acid from the cell, with a loss of 20% total solids and 16% total nitrogen. Water at 120°C removed part of the nucleic acid, and nearly all was extracted by 5% NaCl solution at 120°C. At room temperature, 0.5 N ‐HC1 removed RNA from a suspension of heatkilled yeast. NaOH at a pH of about 12.5 extracted RNA from suspensions of fresh or of heat‐killed yeast. In both cases the cells lost 25–35% solids and a similar proportion of crude protein (Kjeldahl N). The RNA‐reduced yeast preparations may require further treatment, such as extraction with organic solvents, to improve appearance or palatability.