Grains


 

Introduction Grains

 

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Grain is a comprehensive term for plants that belong to the family of grasses (Gramineae) and bear single-seeded fruits. These fruits are known as kernels and are fundamental in the diet of human beings and animals. The cultivation of grain accounts for the largest portion of agricultural production today. Nearly 80% of the grain produced in highly developed countries is used to raise livestock.

The economically most important grains are wheat, rye, barley, oats, rice, maize, millet and triticale. Spelt, einkorn, emmer and QK-77 (Kamut) are all types of wheat. Buckwheat, amaranth and quinoa are also frequently counted as grains, as they also form starchy kernels. Botanically, however, they belong to the polygonaceous plants (buckwheat), the foxtail (amaranth) and the goosefoot (quinoa) plants and are classed under the term pseudo grains. Nevertheless, their assignment to the grains is quite justified in view of their use.

According to when they are planted, cereals are known as either summer or winter grains. A further distinction is made on the basis of how they grow. Cereals whose kernels are tightly attached to the husk are known as husked grains. These include rice, spelt, millet and oats. During the threshing of naked grains (rye, wheat, naked oats and naked barley) the fruit falls out of the husk as a naked kernel.

Grain is frequently referred to as "corn". This generally means the predominant crop of a particular region, such as wheat or rye in Germany, wheat in England, and oats in Scotland and Ireland.

Origin, Area of Cultivation

Archaeological finds show that grains were cultivated in the Middle East 10 500 years ago, in the area of the Tigris and Euphrates rivers. Einkorn and emmer were grown there first, later followed by wheat and barley. These came to Central Europe in the fifth century b.c.

In other areas as well, the cultivation of grains developed, adapted to the given region and to the prevailing climate. Thus rice and millet were grown in China, millet in Africa, maize in America, wheat by the Romans and barley by the northern peoples.

Availability

After it is harvested, grain is normally dried, and if it is stored properly it keeps for a long time and is available throughout the year.

Composition

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

Further, kernels of grain 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 vitamins, minerals and fibres 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. The content of vitamins and enzymes is markedly increased.

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. In case of gluten intolerance (coeliac disease) grains that contain gluten should be avoided. Gluten-free grains are rice, maize and millet, as well as the pseudo grains amaranth, buckwheat and quinoa.

Harmful Substances

Naturally occurring harmful substances in grains are destructive insects, moulds and ergot. Grain that is infested with animal pests such as the Mediterranean flour moth or the rice weevil must be destroyed. The flour mite is practically invisible to the naked eye, and its excreted matter makes the grain inedible. A sweetish smell indicates that flour mites have settled in.

Grain is dried after being harvested in order to prevent the spread of moulds. Proper storage in the private household is therefore imperative. In a humid environment moulds find the optimal conditions for growth.

Ergot is an adhesion that is produced by a fungus in the grain plant. This fungus produces alkaloids, which are poisonous for human beings. Ergot is separated in large part from the kernel after the harvest. Thanks to modern purification techniques it is no longer a great danger. In folk medicine ergot was frequently used as an oxytocic to induce labour.

A harmful substance in the broadest sense is also phytine, which reduces the uptake of minerals and the digestibility of proteins and starches. It is degraded by heating and germination. Soaking groats, for example for fresh muesli, has a similar effect on the phytine. As with the valuable contents, a large portion of the phytine is found in the fruit husk. However, studies show that the higher mineral content makes up for the lesser availability, and whole-grain products supply more nutrients in any case than products made of refined flour.

Quality Criteria, Optimal Storage

Grains are well-suited to stockpiling. Under correct storage conditions it can be kept in the household for up to 2 years. The kernels should be stored dry but not airtight. Direct sunlight should be avoided, and the storage temperature should remain as constant as possible.

It should be taken into consideration that, due to their high fat content, whole-grain flours have a short shelf life and tend to become rancid. It is recommended that they be as fresh as possible and that only the required amount be ground and used within a short time. Refined flours, on the other hand, can be stored for up to 18 months without losing their baking properties. In any case, flours should be stored in well-closed containers to prevent infestation by pests.

Forms of Consumption, Use, Further Processing, Practical Tips for Preparation

Raw grain is normally not consumed, but processed further to flour for use in making baked goods. Or the processed grains, including flours, starches, semolina, brans, groats or flakes, are used to prepare meals. Grain kernels are also used in breweries and distilleries or to produce coffee substitutes. Grain germs are used to produce germ oils.

Particularly with flours there are differences according to the form of processing. The milling grade determines the fineness of the flour. It indicates which components of the kernel were used in the production. A white flour with a low milling grade of 60–70% contains mainly the components of the endosperm; a dark flour with a high milling grade of 75–85% contains components both of the endosperm and of the outer layers and husk.

A further difference results from the classification of flour into types. The flour type corresponds to the mineral content in grams per 100 kg flour. This is found by burning flour in an oven at 900°C and determining the weight of the ashes. In other words, the remaining components that have not burned, which are essentially mineral substances, are weighed and equated with the mineral content. A pale wheat flour type 405 thus contains ca. 4.05 grams of mineral substances per kilogram flour, while a dark whole-wheat flour type 1700 contains approximately 17 grams per kilogram.

In recipes, the word "flour" normally means white flour. When other flours are used the required amount of water is increased: With type 1050 flour ca. 10% more water is necessary and with whole-grain flours even ca. 20% more. Soaking kernels overnight in water greatly reduces their cooking time and increases their digestibility.

Pseudo Grains

The pseudo grains belong to different plant families. In addition, they differ from one another in their plant structure, the height they reach, in their preferred cultivation site and their growth period, in their time of ripeness, and in their temperature requirements and the degree to which they tolerate frost and cold.

Common to all three species, however, is that they form starchy kernels, which differ sometimes considerably with regard to their composition of nutrients. Moreover, they vary in size, form and structure of their kernels. Amaranth forms the smallest kernels, followed by quinoa; buckwheat differs greatly in form and size.

 



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