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).

ORIGINAL ARTICLE: Effect of rendering on protein and fat quality of animal by-products

“…Average total essential and non-essential amino acids content of processed samples (34.6% and 52.7% CP) was similar to that found by Hendriks et al (2002) in 94 MBM samples (36.2% and 60.7% CP). In addition, the concentrations of essential and non-essential amino acids agree with the Degussa database (AminoDataÒ 3.0; Evonik Degussa GmbH, Hanau-Wolfgang, Germany) of 377 MBM samples and are similar to the ranges reported in the literature (Kondos and McClymont, 1972;Hendriks et al, 2002).…”

“…Previous works have shown that when proteins are processed with heat or pressurized steam, amino acids may be destroyed and/or altered and thus become unavailable to animals′ metabolism (Kondos and McClymont, 1972; Wang and Parsons, 1998). Although, the exact mechanisms by which heat and pressure affect amino acids concentration are unknown, the reason may be associated with racemization or cross‐linking of amino acids (Singh, 1991; Shirley and Parsons, 2000).…”

“…Besides lysine and methionine, other essential amino acids, such as threonine, leucine, valine and phenylalanine, were also affected by the rendering process. Kondos and McClymont (1972) studied the effect of different commercial processing conditions (from 116 °C to 160 °C) on the protein quality of meat meals. Lysine, histidine, methionine and arginine were the most severely affected as temperature was increased beyond 140 °C.…”

“…Raw material (Skurray and Herbert, 1974; Johnson and Parsons, 1997; Shirley and Parsons, 2000) and processing conditions (Kondos and McClymont, 1972; Wang and Parsons, 1998; Shirley and Parsons, 2000) have been shown to affect the protein quality of animal meals. Hence, the simultaneous changes in raw material and technological process are likely to have a large influence on the protein value of current MBM.…”

Effects of species raw material source, ash content, and processing temperature on amino acid digestibility of animal by-product meals by cecectomized roosters and ileally cannulated dogs.

“…In contrast, processing temperature has been shown to greatly affect digestibility of AA in animal meals. Kondos and McClymont (1972) reported that the availability of the essential AA in MBM decreased markedly when the processing temperature was increased from 116 to 160°C. In addition, Batterham et al (1986) found that lysine availability in MBM for chicks decreased from 85 to 35% when the processing temperature increased from 125 to 150°C.…”