Composition of oat

The typical composition of wholegrain oat flour and oat bran is presented in the table below:
 

 
Structure of oat grain

The vertical and horizontal cross sections of oat grain are illustrated in the pictures below (click the picture to view it bigger).

Oat Definitions

Proposed, 14th of October 2002, by AACC Oat Products Technical Committee for inclusion in AACC Approved Methods (http://www.aaccnet.org/definitions)

Oat Groat

The oat groat is that portion of the oat kernel which remains after removal of the hull, if present, by physical or other industrial processes. It is botanically known as the caryopsis and is substantially free of non groat material. The groat is considered the whole grain of oats.

Rolled Oats

Rolled oats, also known as oatmeal, is produced from 100 percent dehulled, clean oat groats by steaming, cutting, rolling and flaking.

Whole Oat Flour

Whole Oat Flour is produced from 100 percent dehulled, clean oat groats by steaming and grinding.

Oat Flour

Steel Cut Oats (Steel Cut Groats)

Steel Cut Oats (Steel Cut Groats) are produced from 100 percent cleaned oat groats, which have been coarsely cut into two or more pieces.

Oat Bran

Oat bran is the food which is produced by grinding clean oat groats or rolled oats and separating the resulting oat flour by sieving, bolting and/or by other suitable means into fractions such that the oat bran fraction is not more than 50% of the starting material, and has a total ß-glucan of at least 5.5% (dry weight basis) and a total dietary fibre content of at least 16.0% (dry weight basis) and such that at least one-third of the total dietary fibre is soluble fibre.

Oat Fiber

Oat Fiber is an insoluble fiber derived from oat hulls, which is substantially free of groat components and has an insoluble dietary fiber content of at least 85% (dry weight basis).

Oat Hulls

Oat hulls, as a product of traditional milling processes, are predominantly the fibrous sheath surrounding the oat groat, which consists of an outer and inner layer botanically known respectively as the lemma and palea.

Guideline

To meet requirements of US 21CFR 101.81 Food Labelling for Health Claims, whole oat products should provide at least 4% (dwb) beta glucan soluble fibre and a total dietary fibre content of at least 10% (dwb).

Revisions suggested for consistency of wording: 

Steel Cut Oats (Steel Cut Groats)

Steel Cut Oats (Steel Cut Groats) is produced from 100 percent dehulled, clean oat groats by steaming, and cutting into two or more pieces.

Oat Flour

Oat Flour is finely granulated material derived from steamed, clean oat groats or portions thereof.