Oats are the fourth largest grain crop produced in Australia. Oats almost never have their bran and germ removed in processing so most food products containing ‘oats’, ‘oat flour’ or ‘oatmeal’ as an ingredient contain whole grain oats. Oats are naturally rich in beta-glucan – a soluble fibre found in the bran and endosperm layer of the oat grain. Beta-glucan has been shown to improve blood glucose control after a meal and improves insulin responses as well as decrease cholesterol levels. More recent research indicates oats contain avenanthramides – a unique phytochemical that has been shown to help protect blood vessels from the damaging effects of LDL-cholesterol.
Nutrition credentials of whole grain oats:
- High in carbohydrates (mainly starch).
- The protein content is higher than other cereals, at around 14%.
- High in soluble dietary fibre, specifically beta-glucan found mainly in the aleurone and subaleurone layers.
- The fat content is the highest of all grains (7-8%), with fat contained in the endosperm and the germ. The fat is mostly unsaturated.
- The starchy endosperm of the oat grain contains more fat and protein than other cereal grain.
- High in potassium and low in sodium.
- Contains B-group vitamins such as thiamin, riboflavin, niacin, vitamin B6 (pyridoxine), folate and pantothenic acid.
- Contains vitamin E.
- Contains iron, zinc, magnesium, phosphorus and selenium (depending on the soil content of selenium).
- Contains small amounts of copper, manganese and calcium.
- Contains phytochemicals including lignans, phenolic acids (such as ferrulic and caffeic acids), phytic acid, plant sterols and saponins.
Main culinary uses of oats:
- Oatmeal – Oats are processed to produce oatmeal of various degrees of coarseness. Fine oatmeal (called pinhead) is used in certain types of sausage. Super-fine is used in baking and oatcakes. Medium rough is used by butchers for mealie puddings but can also be used in porridge and baking. Rough is used in porridge. Containing virtually no gluten, fine oatmeal is unsuitable for bread-making, although it can be added to wheat flour for flavour.
- Oat groats – Unlike wheat and rye, oats grow with a husk covering the seed. This husk is not digestible by humans so must be removed from oats before they can be used as food. The husk is removed and then the remaining seed, called the oat ‘groat’, is dried in a kiln so the grain can be stored without spoiling. This kiln drying gives oats their characteristic ‘nutty’ flavour. Oat husks are sometimes added back into porridge oats as an additional source of fibre or may be re-used as a source of fibre in animal feeds.
- Rolled oats – Oat groats are steamed to stop the enzymes from breaking down the naturally occurring fats and reduce rancidity. The steamed oats are rolled to form the traditional rolled oats available in the supermarket. To make quick cooking oats, or instant oats, the oat groat is cut before being rolled. The smaller pieces of oat cook more rapidly but still contain all the nutrients of the whole grain.
- Oat bran – Retaining the bran and outer endosperm material, oat bran is made by a separation process during milling. It is used to manufacture breads, biscuits and breakfast cereals with higher levels of oat beta-glucan.