Gluten is mainly found in wheat, rye, barley and their hybrid varieties. Various foods produced and processed from these cereals, such as bread, cakes, biscuits and beer, generally contain gluten ingredients. Gluten is a mixture of proteins consisting of about 50% prolamins, the main culprits of allergies in humans, and about 50% glutenins. Prolamins are known as gluten in wheat, rye in rye, and hordeolins in barley.

Gluten-free foods: Foods that are not processed using wheat (all Triticum genus plants, such as durum, spelt, and kamut), rye, barley, or their hybrids , the gluten content is not more than 20 mg/kg, it can be called "gluten-free food"; use wheat (all Triticum plants, such as durum wheat, spelled wheat and Kamut wheat), rye, barley Foods processed by or their hybrid varieties can also be called "gluten-free foods" if certain food processing techniques are used to specifically remove gluten components. When the gluten content in the food is not more than 20 mg/kg, it can also be called "gluten-free food"; If the gluten content in the food after the ingredients are processed is between 20 and 100 mg/kg, it cannot be called "gluten-free food".

Gluten-free diet: refers to foods that are completely gluten-free, such as gluten-free bread, pizza, certain fast food and other staple foods. Gluten-free diet is mainly used to treat patients with celiac disease and gluten allergies, but it is also used by some celebrities and athletes as a weight loss and fitness food. A gluten-free diet means foods that are completely free of gluten. Eating a gluten-free diet means strictly abstaining from foods containing wheat gluten, such as pasta, pizza, beer, cheese, sandwiches, etc., and even delicate foods such as sauces, cakes, breads, biscuits and cakes, and instead eating potatoes, Mainly corn, vegetables, meat, beans, nuts, dairy eggs, seafood, rice, etc., and buy foods labeled gluten-free.