Recovery of Meat Protein From Alkaline Extracts of Beef Bones

Coagulation of protein from aqueous alkaline meat extracts by acidification, heating, and freezing‐thawing, was studied between pH 7.0 and 4.5. Protein recovery in excess of 90% was possible by heating momentarily to 80°C or higher at pH 5.0‐6.0, but the coagulum was gritty and uncohesive. Lower yields were obtained by mild heating to 60°C, acid coagulation at pH 5.0 and 5.5, and by rapid freezing to ‐30°C and thawing of the pH‐adjusted extracts. The unheated coagula were cohesive and had good binding properties as determined by texture and sensory tests. Freezing‐thawing at pH 6.0 produced a highly structured material. All coagula contained typically 85‐87% moisture, lo‐12% protein, and less than 0.4% ash. Loss of flavor was the main sensory defect noticed after heating.