Table of content A-Z


flour and cereal products




Flour and cereal products are among the most important staple foods for human beings. The most relevantare products made of wheat, rice, corn (maize), millet, oats, barley and rye: approximately 80% of the entire area under cultivation is planted with these varieties, and 50% of the nutritional energy required in the world stems from their products. In Europe wheat, barley, rye and oats are the most important varieties, in the USA it is corn. Almost half of the entire grain produced is fed to animals raised for slaughter, however.

The manufacture and characteristics of cereal products

The grains of free-threshing, or naked, varieties (e.g. naked wheat, rye) fall more or less by themselves out of the husks during harvesting, i.e., during threshing, and are then collected in the combine harvester, while the straw and the husks fall back on the field.

The grains of the so-called spelt varieties (e.g. oats, spelt or dinkel wheat)sit more tightly in their husks. After threshing they must be scraped out. For this purpose, the dried grains are dashed against walls mechanically or are sanded, which releases them from their hulls. Likewise, during or directly following the harvest, the grains are roughly cleaned. This means that impurities such as seeds of weeds, ergot, stones and insects are detected and removed by cleaning machines or special devices in the combine harvester. In this condition the grains can then be stored in silos or halls.

Since human beings cannot digest the raw, whole grains, they must be ground. The result is a variety of cereal products.

Flour products:

* Coarse-grained flour is a ground-wheat product between flour and semolina in size. Like the latter, it contains no husks and thus very few vitamins and minerals. Coarse-grained flour is used to make fine yeast pastries and pasta.

* Pearl barley consists of husked, peeled grains freed of their germ buds. With naked oats husking is of course unnecessary. The pearls are white because they are sanded and polished several times. To make pearl barley, the sanded grains are cut into two to four parts and again sanded and polished until they are round as desired. Broken grains can also be used for this purpose.

* Semolina is actually the term for pieces of cereal grains between 250 and 1000 µm in size that result from grinding and that are coarser than flour. Semolina from both durum wheat and common wheat is sold.Both types consist of the husk-free endosperm of the wheat kernel and are thus virtually free of vitamins and minerals and contain mainly starch. Durum wheat semolina is usually light yellow and coarse. Even when cooked it remains grainy, but the grains form a good coherency, making it suitable for dumplings and noodles. Common wheat semolina is almost white. It loses its graininess when cooked, so that it is good especially for porridge and soups.

* Groats denotes husked and coarsely ground kernels, usually from oats, barley or buckwheat, with a size between that of pearl barley and that of semolina. It is well-suited for porridge, dumplings and soufflés or baked puddings.

* Branisa residue of flour production. It consists of the outer layers of the kernel that are sifted out after polishing, i.e., hulls and parts of the aleurone layer and of the germ bud. Impurities adhering to the outer layer are also contained in the bran. Edible bran is a componentof dietary preparations today because it contains much fiber, large amounts of protein and some vitamins.

* Flour constitutes the greatest quantity among cereal products. It is obtained by grinding the kernels – either the endosperm alone, with or without the surrounding aleurone layer, or practically the entire kernel including the germ. This is termed the level of extraction: flour containing more of the kernel has a higher level of extraction. Grinding the endosperm with the germ and the hull produces a dark whole-grain flour. For white flour the kernels are first polished, separating the hull and possibly the aleurone layer and the germ from the endosperm.

The type of flour depends on the portion of whole kernel contained in the final product. The higher the type number, the more of the kernel has been processed. The number denotes the ash content of the flour, i.e. how many grams of ash, consisting of minerals, remains after 100 g of flour is incinerated. Type 405 flour contains 405 mg ash per 100 g flour.

With the same level of extraction, rye flours contain more vitamins than wheat flours do.

* Coarse-ground wholemeal consists of coarsely ground kernels of grain. Like flour, coarsely ground wholemeal contains all components of the entire kernel, and that used for baking contains all but the germ.

Hulled products:

* Flakes are produced when hulled and steamed, mostly whole, kernels of grain are crushed between hot rollers. This makes them flat and oval. The heat during steaming inactivates the enzymes that would otherwise make them bitter. Flakes are particularly easy to digest. Surely the best known are oat flakes, of which there are three types: crunchy rolled oats from whole kernels, tender flakes from groats (see above) and instant flakes / baby flakes from finely ground kernels. The latter dissolve completely when they are added to a liquid.

Other grain products:

* Bulgur is a traditional food in the Middle East,made of wheat.To produce it industrially, wheat kernels are soaked, treated with hot steam and dried. By means of this parboiled process, with which we are familiar in connection with rice, the greater part of the minerals and vitamins contained in the outer layers of the kernel are pressed inside and thus are retained even after subsequent hulling and polishing. The dried kernels are sold packaged and can be stored for a relatively long time. In private households, the washed wheat is cooked or soaked for several hours and then dried. The bran is rubbed off in a mortar.

* Couscous is made from either millet or durum wheat semolina. In some cases the two grains are mixed. The grain is usually husked and coarsely crushed. Wholemeal couscous is made from kernels that are not hulled and is identifiable by its dark colour. The millet or the semolina is then pre-cooked, pressed and dried. This easily digested cereal product is easy to prepare by cooking the grains and letting them soak in hot water. It is suitable as a separate dish, as a side dish or as a component of salad.

* Green spelt, or Grünkern, is a product known above all in southern Germany. Triticumspelta, a variety of wheat, is harvested green and roasted in the ear. This roasting, or drying, is a procedure in which water is removed from the kernels by warm air that is blown through the loosely layered ears usually from below. This means it can be stored longer.

* Malt is prepared from germinated grain that is then dried. During germination, the soaked kernels begin to form enzymes that are able to convert starch into sugar. This is important for brewing, which is the most common way in which malt is further processed. With roasting, the continued formation of enzymes and the conversion of starch to sugar are stopped and the malt is dried. Depending on the type of malt and the temperature, different aromas and dyestuffs are formed.

* Sprouts are germinated grains that can be eaten as a vegetable or salad.

* Starches account for 55–80% of the carbohydrates present in grain. They are extracted from grain and used directly in other products as native starches, or they are further processed to modified starch that fulfills special technological purposes (for example, particularly good swelling properties or resistance to heat). Some starches are bleached with sulphur dioxide(SO2). This serves only to enhance the appearance and provides no other advantages. Unfortunately, some of the bleach remains in the end product and can be harmful to the consumers’ health even in small concentrations. It is important that sulphur dioxide in the human body be degraded quickly, so that it cannot form any compounds with amino acids, proteins and other substances and disturb a very sensitive balance. Common reactions to an excessive amount of sulphur are pseudo allergies; asthmatic patients in particular should be very careful in this respect.


All grains and the products made from them should always be stored dry and airtight. In this way, kernels can be kept for several years and packaged light wheat flour for about 1 year. Dark, more highly extractedflours have a shorter shelf life. The more hull fragments the product contains, the more bacteria and mould spores can adhere to them and the quicker the product must be used. Wholemeal flours and wheat germ have a very short shelf life.
In contrast, finely ground wholemeal has a shorter shelf life than coarse-ground. The contents of moisture and fat are also important for the length of storage: Products with a high fat content such as oats, rice or millet must be used up more quickly or pre-treated. Brown rice, oat flakes and similar products should also not be kept for too long and should be taste-tested prior to use; slightly bitter aromas and a scratchy throat are indications of fat degradation. Such products should be discarded. On the other hand, parboiled rice can be stored for quite a long time. With all cereal products, a sweet smell (unpleasant) indicates mite infestation.

Advice for household use: Fill dried cereal products such as flour, flakes, muesli, rice, noodles, etc., as well as packet soups, raisins, and all other long-life kitchen basics that you don’t wish to use right away in separate airtight containers. In case one of these products was already infested with pests such as moths or with mould when you bought it, these will not be able to spread to the other stored goods and you will have to discard only the affected product and disinfect its container.


An average kernel of grain consists of 70% starch (carbohydrates), 12% water, 11% protein, 2% fat and 7–9% fibre. Owing to its high starch content, grain is considered to be an important source of energy in the human diet.

Grain kernels also contain the essential minerals and trace elements iron, phosphorus, zinc, manganese, and potassium, as well as vitamins, mainly vitamin E and the B-vitamins, above all thiamine and folic acid.

The nutrient content is subject to natural variations in climate and in soil properties, but it is also influenced by fertilization. Moreover, nutrient contents vary between the different types of grain and between the individual components of the kernel. Thus the endosperm contains mainly starch and protein. The majority of the vitamins, minerals and fibre are found in the outer layers of the kernel. In the germ there is a large amount of protein, with a high content of essential amino acids. The fat is composed largely of unsaturated fatty acids. Numerous vitamins and minerals are also found in the germ, in larger quantities than in the endosperm.

The sprouting of the germ increases its health value. During germination, conversion processes are started by which proteins, carbohydrates and fat are broken down into their individual components. This markedly increases the content of vitamins and enzymes.

Some grains contain gluten, an elastic protein substance. Among these are wheat, spelt, rye, barley and oats. Gluten provides good baking properties, but not all grains that contain gluten are suitable for baking. Persons with gluten intolerance (coeliac disease) should avoidgrains that contain gluten. Gluten-free grains are rice, maize and millet, as well as the pseudo grains amaranth, buckwheat and quinoa.

When grain is processed to make flour and cereal products many of the valuable ingredients are lost, because the parts of the kernel that contain the majority of vitamins and minerals (i.e. husk, germ bud and aleurone layer) are frequently removed. For wholemeal products the entire kernels are processed, giving them the largest share of minerals and vitamins.

Almost no dangersto health

The consumption of grains and cereal products carried a greater health risk in earlier times than it does today because the plants were more frequently infested with the ergotfungus. Thanks to modern treatment methods, however, this problem is by and large under control. Contamination with heavy metals and herbicides is also negligible. Since entire kernels including the husks are used for wholemeal products, these are – like brans, which consist only of the husk layers – more contaminated with harmful substances than are flours with a low extraction grade, groats, pearl barley, flakes, bulgur, and so on.

Cereal products

Cereal products are manufactured from minimally processed grains.

*Flakes are extruded milled grain products. The milled products are foamed with water under certain conditions of temperature and pressure.

* Gluten is the term for several water-insoluble protein complexes that are found in variable amounts in the endosperm of certain kernels and have varying characteristics. One of the most important, for example, wheat gluten, determines the shapeability and elasticity of doughsand a loose crumb for bread. Maize gluten, on the other hand, is unfit for human consumption and is used mainly as animal fodder or as a raw material in the production of spices. Some people cannot tolerate gluten (coeliac disease); for them, baked goods can be made from gluten-free grain varieties such as buckwheat or rice.

* Muesli usually consists of flakes, groats and sometimes bran from various sorts of grain. It is generally a wholemeal product. Mueslis are supplemented with oil seeds (e.g. flax, sunflower), nuts (e.g. coconut, hazelnuts/filberts, peanuts), flakes and dried fruits (usually raisins). Many mueslis on the market are sweetened with honey. In many cases the cereal products are heated prior to their use in muesli in order to ensure a long shelf life.

* Noodles consist mainly of semolina or flour. Pasta is made from a dough containing only durum wheat semolina and water. Other noodles have egg as an additional ingredient.

* Popcorn is puffed kernels of maize (Zea mays var. microsperma). Due to the heat during puffing, products of caramelisation and roasting are formed which give popcorn its typical flavour. Oil or butter and sugar or salt are added according to taste while the kernels are heated.

* Puffed rice also takes on the aromas of caramelisation and roasting when it is heated.

* Edible oil can be extracted from various sorts of grain. Both the seeds and the germ buds (e.g. wheat germ oil) may be used. More information can be found under “Fats and Oils”.




  With the website the Fritz Terfloth Foundation of Münster offers consumers independent and competent information about plant foods and their health effects. All texts are subject to German copyright law. Information about the conditions for use of the texts by third parties can be found here.

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