Nutritional evaluation of meat meals for poultry. VII.* Effect of processing temperature on total and biologically available amino acids

Abstract

The effect on the protein quality of meat meals of processing them under commercial conditions in a continuous dry renderer at maximum temperatures ranging from 116 to 160°C for a running time of 115 min was studied. Although the total levels of amino acids were little affected by processing temperatures, the biological availability of all essential amino acids, as determined by the protozoan Tetrahymena pyriformis, was reduced as the processing temperature increased. At 140 and 160°C the availability of certain amino acids was reduced by 37-56%, lysine, histidine, and methionine being the most severely affected. The availability of essential amino acids in meals produced at temperatures from 121 to c. 138° was not significantly different. The growth-promoting ability of the meat meals for chickens was closely related to the availability of the essential amino acids. __________________ *Part VI, Aust. J. Agric. Res., 19: 171 (1968).