Relationship between meat toughness and properties of connective tissue from cows and young bulls heat treated at low temperatures for prolonged times

The aim of the current study was to elucidate whether cows and young bulls require different combinations of heating temperature and heating time to reduce toughness of the meat. The combined effect of heating temperature and time on toughness of semitendinosus muscle from the two categories of beef was investigated and the relationship to properties of connective tissue was examined. Measurements of toughness, collagen solubility, cathepsin activity and protein denaturation of beef semitendinosus heated at temperatures between 53 °C and 63 °C for up to 19 1/2 h were conducted. The results revealed that slightly higher temperatures and prolonged heating times were required to reduce toughness of semitendinosus from cows to the same level as in young bulls. Reduced toughness of semitendinosus as a result of low temperature for prolonged time is suggested to result from weakening of the connective tissue, caused partly by denaturation or conformational changes of the proteins and/or by solubilization of collagen.