Oat groats

Milling is made up of numerous steps, the most important being dehulling to expose the digestible groat, heat processing to inactivate enzymes that cause rancidity, and cutting, rolling or grinding to convert the groat into a product that can be used directly in oatmeal or can be used as a food ingredient in products such as bread, ready-to-eat breakfast cereals and snack bars.

Dehulling is a process separation of the outer hull from the inner oat groat is effected by means of centripetal acceleration.

Oat groats are cleaned oat kernels that have had their inedible hull removed and take the longest to cook. Steel cut groats are groats that have been cut into 2–3 pieces with a sharp metal blade. They are often referred to as Irish oatmeal and cook faster than whole oat groats.

Oats have a hull that consists mainly of cellulose, hemicelluloses and lignin. Within the hull is the groat, which comprises 68–72% of the kernel.

The outer layer of the groat is an important source of protein, neutral lipids, b-glucan, phenolics and niacin, and is sometimes separated from the groat to produce oat bran.

Groat size affects the maximum size of the flake that can be generated. Also, the mass of the groat relative to the mass of the oat grain is referred to as the groat percentage, and is the principal factor affecting milling yield.

Oatmeal is ground rolled oats. Quick and instant oats are oat flakes that have been cut, then rolled thinner and steamed longer, ultimately resulting in a change in texture and decreased cooking time.
Oat groats