Meat The species, breed, age and part of the animal are all factors which contribute to the sensory and nutritional qualities of meat. Meat which is tender and cooks quickly is usually from a young animal, eg lamb. Meat which is from an older animal is tougher due to its age and needs a longer and slower method of cooking. It is made up from long thin muscle fibres. These are bound together in bundles by thin sheets of connective tissue.
Connective tissue is made up from basic proteins - collagen, elastin and reticulin.
Each protein has specific characteristics and reacts differently when meat is cooked. Collagen is weakened by heat and forms gelatin, which is soluble. This change helps the meat to become tender. The two other proteins are not weakened by heat, yet provide elasticity and strength. Reasons for this include the type of animal, its age, level of activity and the part of the animal eaten.