Heavy collagen, such as tendons at the ends of muscle groups and the protein elastin, does not break down under this cooking process and is therefore insoluble in water. (We discuss cooking potential and tenderness in more detail later in the book.) The collagen dissolves in the water, which is why stocks made from animal bones and connective tissue have body and thicken when cooled. In contrast, tougher cuts from the front quarter of beef that have more collagen connective tissue, such as the blade, shoulder, and shank, require a moist heator combination cooking method, which breaks down collagen into a gelatinform when cooked in water at temperatures of over 80☌ (176☏). The most tender cuts from a beef animal, such as tenderloin, strip loin, and top sirloin from the beef hind quarter, can be prepared using a dry heat cooking method.

This is why older animals are usually tougher and younger animals are more tender. For example, as an animal ages, it has more connective tissue and therefore experiences cross-linking, an increase in connective tissue that becomes highly insoluble. The amount of connective tissue in meats and its solubility (the degree to which it is dissolved during the cooking process) can directly influence the tenderness of meat muscle. Licensed under CC BY 3.0 via Wikimedia Commons 1007 Muscle Fibres (large) by OpenStax College – Anatomy & Physiology, Connexions Website. The thin filaments, known as actin, contain two other proteins called troponin and tropomyosin that help regulate muscle contraction. The thick filaments are the contractile protein myosin. One unit of a bundle is called a sarcomere, or little muscle. The muscle fibres are known as myofibrils, which are composed of thick and thin filaments arranged in a repeating pattern alongside the other myofibrils (Figure 3). Bone with tendon attached (left) and muscle removed (right). Crosscut of beef shank showing muscle fibres. The tendon is attached to the bone at or near a bone joint (Figure 2). On larger bones (such as the shanks of larger animals), it is easy to see the muscle groups in bundles (if cut on the cross-section) surrounded by collagenfibres and a much heavier connective tissue ( elastin) that forms a thin covering (called silverskin) separating muscle groups or a tendon at the ends of the muscle group (Figure 1). Muscle contains 60% to 70% moisture, 10% to 20% protein, 2% to 22% fat, and 1% ash, depending on type and species. Meat muscle, which is what we eat, is made of fibres, bound together with connective tissue, that are mainly linked to other groups of muscles or directly to the animal’s bone structure.

Xsection of muscle