Avena sativa L.
Oat, is an annual crop, grown, mainly in the temperate regions because it can tolerate very cold temperatures and very moist conditions. It’s grown for its seed, also known as kernel or groat..
The grain has been a staple food in Scotland for years, but has mostly been used elsewhere, for animal feed and has gained very little popularity with consumers. Over the years, the interest in Oats has been growing because of highly publicized studies showing that oat bran can lower cholesterol levels when eaten as part of a low fat diet.
The grain also offers impressive levels of iron, magnesium, calcium, phosphorus, potassium, B vitamins, vitamin E and zinc.
Oats is also an excellent source of soluble and insoluble dietary fibre. The soluble fibre is mostly due to the presence of a complex carbohydrate called beta glucan, which is primarily responsible for lowering cholesterol levels. Oat bran contains more dietary fibre than oatmeal and other forms of oats, but all types of oat products have some bran since the grain is not refined (the bran and germ are not removed).
Compared to other cereals, oat has a high protein content and a good amino acid profile, with a high level of lysine. It contains 50 percent more protein than bulgur wheat, and twice as much as brown rice. The proteins found in oat are: avenalin, which is 80 percent storage protein and avenin.
Of all the cereal grains, oats has the second highest lipid content after maize (corn), with a high proportion of unsaturated fatty acids. The lipids are mainly found in the endosperm.
Once the oat is harvested in the field, it’s brought to the mill where it undergoes dehulling, which is the removal of the outer hull or chaff or husk, leaving behind the wholegrain kernel or edible seed or grain.
The wholegrain kernel is known as groat and has the germ or embryo, outer rich bran and endosperm, intact. They are high in fat (lipids) and exposure of the grain to air can result in breakdown of lipids by lipolytic enzymes, which causes a rancid flavour. In order to stabilize, and prevent the kernels (grains) from going rancid, they undergo heat and moisture treatment to deactivate the lipolytic enzymes. This gives them a nutty flavour.
The groat can undergo milling, rolling or cutting, using steel blades, to produce different types of oatmeal, namely, steel cut oats, rolled oats also known as oat flakes, oat bran and oat flour (debraned and whole grain).
Since neither the bran nor the germ is removed from oats, almost all forms of the grain are equally nutritious. The oat bran is more nutritious.
Use of Oats:
- Oats are an excellent source of complex carbohydrates and is is mostly eaten as hot oatmeal but also as an ingredient in cold cereals, granola, and muesli, meat extenders, beverages, and baby foods.
- It’s also used in baking oatmeal cookies, muffins, cakes and breads.
- In Britain, it’s used for brewing a beer called oatmeal stout. In Latin America, a cold sweet drink called Avena, is made from ground oats and milk.
- In Ethiopia oat flour is made into ‘injera’ (pancake-like bread), ‘tella’ (local beer) and other products.
- In industrialized countries oat grain mainly finds application as animal feed, especially for horses, but also for cattle, sheep, turkeys and other animals.
- The straw is used as forage and in Ethiopia, it also serves as bedding for livestock, is used for fuel and roofing material for traditional houses It makes good hay and silage or is grazed by animals.