β –glucan in oat bran

In anatomical term, cereal bran is considered to be the outer layers of the kernel, which include a number of morphologically distinct layers ending in going from the outside into the kernel, with the aleurone cells. Bran is prepared for the whole grain oat flour by removing the starchy endosperm using sieving or air classification.

The amount of starchy endosperm remaining in the bran varies from product to product. Cereal (1-->3)(1-->4) β –D-glucan commonly referred to as  - glucan, occurs in the sub-aleurone and endosperm cell walls of the grain.

Although the minimum suggestion 5.5% β–glucan, commercial regular oat bran contains typically 6-8% β-glucan, whereas novel oat bran concentrates from dry milling process can contain up to 22% β-glucan.

By wet extraction processes very pure β-glucan extract (β-glucan content even over 90%) can be produced.

In addition, to β-glucan, oat bran also contains other dietary fiber components, pentosans, and insoluble fiber, so that the total dietary fiber content in oat bran product is 17-35% this is considerably higher than in oat flakes which typically contain 10-12% dietary fiber.

Since β–glucan is the major component of the endosperm cell walls, the thick sub-aleurone walls represent a particularly rich source and contribute to the higher β -glucan content of bran.

Oats, rolled oats, and oat bran concentrates, extruded flakes, macaroni, muffins and porridge contained β -glucan with a high average molecular weight, while pasteurized apple juice, fresh pasta and a tea contained degraded β -glucan.

Two functional foods rich in oat β –glucans have been developed: a breakfast cereal and a snack bar.
β –glucan in oat bran