The amino‐acid composition of processed bones and meat

Quantitative amino‐acid analyses were made by ion‐exchange chromatography on two samples of commercial feeding meals containing high contents of meat and bone, respectively, after processing in an Iwel cooker and acid hydrolysis. The processed bones had an amino‐acid composition close to that of collagen with slightly larger amounts of most essential amino‐acids. The meat material contained significantly higher amounts of essential amino‐acids than the processed bones and had an overall composition intermediate between whole muscle protein and collagen. The hydroxyproline contents, supported by values for other amino‐acids, indicated that the protein from processed bones contained about 83%, and the meat protein some 58%, of collagen, and that in commercial meat and meat‐and‐bone meals 50 to 65% of the total protein was collagen. Since collagen is deficient in several essential amino‐acids, its presence in large amounts may be expected significantly to reduce the nutritional value of the total protein of feeding meal. It is suggested that the determination of hydroxyproline could form the basis of a simple method for the assessment of protein quality in meat and bone meals.