The tensile properties of frozen and thawed lean beef

The tensile properties of frozen beef are relevant to many size reduction operations in frozen meat processing. The tensile properties of lean beef aligned both along, and perpendicular to, the fibre direction have been studied over the temperature range +10°C to -30°C and over a range of strain rates. Strain rate had an effect on tensile strength and other tensile parameters for frozen beef with either fibre orientation. Two distinct types of behaviour were observed. At the higher temperatures (e.g. -5°C and -10°C for beef oriented perpendicular to the fibre direction) there was a rise in tensile strength with increase in strain rate. This viscoelastic fracture behaviour can be attributed to the viscoelastic character of meat proteins and also to the plasticity of ice. At the lower temperatures (e.g. -15°C to -30°C for beef oriented perpendicular to the fibre direction) there was a decrease in tensile strength with increase in strain rate. This fracture behaviour can be attributed to the brittleness of ice. Temperature had a marked effect on all tensile parameters. The maximum tensile strength at most strain rates occurred in the temperature range -10°C to -20°C, and the strength was lower at -30°C than at -20°C.