Although gluten has gained a bad reputation, the majority of people would struggle to explain what it actually is. The truth is that gluten is just a mixture of proteins found in the seeds of certain cereal plants: wheat, rye, and barley. Gluten is stored in a tissue inside the seed called endosperm, which surrounds the plant embryo and provides a dense source of energy as the plants starts to grow. In wheat, gluten is formed when the proteins glutenin and gliadin cross-link into a net-like structure that provides elasticity (stretchiness) and viscosity (thickness).

    Once food reaches the stomach it must be broken down by enzymes in the process of digestion. Large proteins are broken up into chains of amino acids called peptides. Normally these peptides are easily broken down further; however, the gliadin peptides in gluten are difficult to break down as they are a part of a group of peptides called prolamins. Prolamins are made up of lots of glutamine and proline amino acids, which digestive enzymes have difficulty breaking up. This means that unlike most proteins gluten digestion can leave strands of amino acids intact in the small intestine. These strands can be up to 10 amino acids long and are known as oligopeptides. For most people gliadin oligopeptides are harmless. However, a small proportion of the population will produce an immune response known as coeliac disease, a condition caused by the body’s immune systems mistakenly attacking itself. Coeliac disease is caused by a reputation to gluten. 

This passage would probably be assigned reading in which of the following course?