Improved protein recovery from some meat industry by-products

The proportion of protein recoverable from bovine heart, kidney, liver, lung, rumen and spleen by alkaline extraction, followed by reacidification, was found to be related to the temperature of extraction, the recovery of both lung and rumen protein at 60°C being approximately twice that at 0°C. Extraction for more than 2 h gave increases in protein recovery. The increased protein solubility was partly due to increased solubilisation of collagen and to a reduction in the quantity of protein precipitated by acidification. Alkaline extraction of lung and rumen at 60°C resulted in the formation of the dipeptide lysinoalanine (0·39 and 0·49 g/16gN, respectively), with tracev amounts at 20°C and 40°C. The electrophoretic patterns of raw meat industry by-products are discussed in the light of previous findings.