AMINO-ACID-COMPOSITION AND NITROGEN-TO-PROTEIN CONVERSION FACTORS FOR ANIMAL AND PLANT FOODS

Five multi-N (Gln, Asn) and basic amino acids (Lys, Arg, His) constituted one-third of the total amino acids in 23 food products. Wide variations in composition of these amino acids plus Glu, Leu, Pro, and Val had a marked influence on the nitrogen-to-protein (N:P) conversion factors. These N:P factors ranged from 6.02 to 6.15 for dairy products, from 5.61 to 5.93 for egg, meat, fish, and cereal products, and from 5.14 to 6.26 for legume, root, tuber, vegetable, fruit, and microbial foods. The average N:P factor was 5.68 ± 0.30, and a common N:P factor of 5.70 is recommended for use in all mixed or blended foods or diets where accurate protein values are required for nutritional applications. © 1990, American Chemical Society. All rights reserved.