The common oat (Avena sativa) is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural, unlike other grains). While oats are suitable for human consumption as oatmeal and rolled oats, one of the most common uses is as livestock feed. Oats make up a part of the daily diet of horses, about 20% of daily intake or smaller, and are regularly fed to cattle as well. Oats are also used in some brands of dog food and chicken feed. Oat seeds are commonly marketed as cat grass to cat enthusiasts, since cats will readily harvest and eat tender young oat, wheat and some other grass sprouts.
Oats have numerous uses in food; most commonly, they are rolled or crushed into oatmeal, or ground into fine oat flour. Oatmeal is chiefly eaten as porridge, but may also be used in a variety of baked goods, such asoatcakes, oatmeal cookies, and oat bread. Oats are also an ingredient in many cold cereals, in particularmuesli and granola. Oats may also be consumed raw, and cookies with raw oats are becoming popular.
Oats are also occasionally used in several different drinks. In Britain, they are used for brewing beer. Oatmeal stout is one variety brewed using a percentage of oats for the wort. The more rarely used oat malt is produced by the Thomas Fawcett & Sons Maltings, and was used in the Maclay Oat Malt Stout before Maclays Breweryceased independent brewing operations. A cold, sweet drink made of ground oats and milk is a popular refreshment throughout Latin America. Oatmeal caudle, made of ale and oatmeal with spices, was a traditional British drink and a favorite of Oliver Cromwell.
In Scotland, a dish called sowans was made by soaking the husks from oats for a week so that the fine, floury part of the meal remained as sediment to be strained off, boiled and eaten. Oats are also widely used there as a thickener in soups, as barley or rice might be used in other countries.
Oats are also commonly used as feed for horses – as crimped or rolled oats or as part of a blended food pellet. The oat hull must be crushed (“rolled” or “crimped”) for the horse to digest the grain. Cattle are also fed oats, either whole, or ground into a coarse flour using aroller mill, burr mill, or hammer mill.
Oat straw is prized by cattle and horse producers as bedding, due to its soft, relatively dust-free, and absorbent nature. The straw can also be used for making corn dollies. Tied in a muslin bag, oat straw was used to soften bath water.
Oats are generally considered “healthy”, or a health food, being touted commercially as nutritious. The discovery of the healthy cholesterol-lowering properties has led to wider appreciation of oats as human food.
Oats contain more soluble fibre than any other grain, resulting in slower digestion and an extended sensation of fullness. One type of soluble fibre, beta-glucans, has proven to help lower cholesterol.
After reports of research finding that dietary oats can help lower cholesterol, an “oat bran craze” swept the U.S. in the late 1980s, peaking in 1989, whenpotato chips with added oat bran were marketed. The food fad was short-lived and faded by the early 1990s. The popularity of oatmeal and other oat products again increased after the January 1998 decision by the Food and Drug Administration (FDA), when it issued its final rule allowing a health claim to be made on the labels of foods containing soluble fibre from whole oats (oat bran, oat flour and rolled oats), noting that 3.00 grams of soluble fibre daily from these foods may reduce the risk of heart disease. To qualify for the health claim, the whole oat-containing food must provide at least 0.75 grams of soluble fibre per serving. The soluble fibre in whole oats comprises a class of polysaccharides known as beta-D-glucans.
Beta-D-glucans, usually referred to as beta-glucans, comprise a class of indigestible polysaccharides widely found in nature in sources such as grains,barley, yeast, bacteria, algae and mushrooms. In oats, barley and other cereal grains, they are located primarily in the endosperm cell wall.
Oat beta-glucan is a soluble fibre. It is a viscous polysaccharide made up of units of the monosaccharide D-glucose. Oat beta-glucan is composed of mixed-linkage polysaccharides. This means the bonds between the D-glucose or D-glucopyranosyl units are either beta-1, 3 linkages or beta-1, 4 linkages. This type of beta-glucan is also referred to as a mixed-linkage (1→3), (1→4)-beta-D-glucan. The (1→3)-linkages break up the uniform structure of the beta-D-glucan molecule and make it soluble and flexible. In comparison, the indigestible polysaccharide cellulose is also a beta-glucan, but is not soluble. The reason it is insoluble is that cellulose consists only of (1→4)-beta-D-linkages. The percentages of beta-glucan in the various whole oat products are: oat bran, greater than 5.5% and up to 23.0%; rolled oats, about 4%; and whole oat flour about 4%.
Oats, after corn (maize), have the highest lipid content of any cereal, e.g., greater than 10 percent for oats and as high as 17 percent for some maize cultivars compared to about two to three percent for wheat and most other cereals. The polar lipid content of oats (about 8–17% glycolipid and 10–20% phospholipid or a total of about 33%) is greater than that of other cereals, since much of the lipid fraction is contained within the endosperm.
Oat protein is nearly equivalent in quality to soy protein, which has been shown by the World Health Organization to be equal to meat, milk, and egg protein. The protein content of the hull-less oat kernel (groat) ranges from 12 to 24%, the highest among cereals.Oats are the only cereal containing a globulin or legume-like protein, avenalin, as the major (80%) storage protein. Globulins are characterised by solubility in dilute saline. The more typical cereal proteins, such as gluten and zein, are prolamines (prolamins). The minor protein of oat is a prolamine, avenin.
Coeliac, or celiac, disease, is often associated with the ingestion of wheat, or more specifically, a group of proteins labelled prolamines, or more commonly,gluten. Oats lack many of the prolamines found in wheat; however, oats do contain avenin. Avenin is a prolamine that is toxic to the intestinal mucosa of avenin-sensitive individuals, and can trigger a reaction in these coeliacs.
The most recent research indicates that some cultivars of oat can be a safe part of a gluten-free diet, because different varieties of oat have different levels of toxicity. Although oats do contain avenin, there are several studies suggesting that this may not be problematic for all celiacs. The first such study was published in 1995. A follow-up study indicated it is safe to use oats even in a longer period.
Additionally, oats are frequently processed near wheat, barley and other grains, such that they become contaminated with other glutens. Because of this, the FAO‘s Codex Alimentarius Commissionofficially lists them as a crop containing gluten. Oats from Ireland and Scotland, where less wheat is grown, are less likely to be contaminated in this way.
Oats are part of a gluten-free diet in, for example, Finland and Sweden. In both countries, there are “pure oat” products on the market.
Information courtesy Wikipedia}