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rapeseed

 

Synonyms: rape, canola, colza; botanical name: Brassica napus


Rapssaat

 

Rape has been cultivated in Europe for centuries. It was brought to Middle Europe in the Middle Ages and has been used ever since to produce oils. Rape originated in the eastern Mediterranean region.

After petroleum was introduced in the 1860s the cultivation of rape was drastically reduced. During the Second World War it increased again – rape was used to manufacture margarine – but it failed to gain acceptance following the war. Only since the 1980s has it been cultivated in great amounts, and it is becoming more and more popular, thanks to increased research and new breeds.

In addition to Germany, rape is grown in China, Canada, the area of the former Soviet Union, India, Pakistan and Japan, as well as in numerous other countries.


Availability


With the new breeds, varieties were created that had many advantages over the old ones and were better received. Varieties that contain only approximately 0.1% erucic acid are known as 0 rape. Erucic acid is a fatty acid that has been replaced by the unsaturated fatty acid oleic acid, which is considerably more digestible by the human body. Varieties are known as 00 rape (double-zero rape) which, in addition to the reduction of erucic acid, are also low in glucosinolates. We differentiate as well between summer and winter rape.


Appearance, taste, characteristics


Like cabbage and mustard, rape is botanically speaking a cruciferous plant. It is unmistakeable in May when the radiant yellow blossoms present themselves in all their splendour. A single rape plant carries up to 100 such yellow blossoms.

The round, brown to red-brown seeds have a diameter of ca. 1–2 mm. After the plant has been pollinated, up to 2500 seeds form in a pod. They are used to extract an edible oil that is bright yellow, just like the blossoms.

Rape is of great importance in agriculture; it loosens and aerates the soil, which increases the yield of the plants that are subsequently grown in it.


Ingredients


The seeds contain about 40–50% fat and up to 20% protein. As already mentioned, the content of erucic acid and gluosinolates has been reduced in many varieties.

At this point we should list exactly the components of rapeseed oil. It contributes greatly to supplying the vitally important fatty acids. The proportions or omega-3 and omega-6 fatty acids is optimal. They should be consumed in a ratio of 1:2, and rapeseed oil supplies this almost exactly.

Saturated fatty acids should make up maximally 10% of the total energy requirement per day, unsaturated fatty acids about 20%. The content of saturated fatty acids in rapeseed oil is very good at around 8 g per 100 g.

Vitamin E is present in particularly high amounts, but to fulfil the daily requirement one would have to consume more than 50 g of rapeseed oil per day.

100 g contain:

Rapeseed oil
Energy (kcal)
825
Water (g)
<1
Protein (g)
0
Fat (g)
99
Carbohydrates (g) (g)
0
Fibre (g)
0
Vitamin A (RE) (µg)
550
Vitamin E (mg)
23
Saturated fatty acids
7,7
Omega-3 fatty acids (g)
9,5
Omega-6 fatty acids (g)
22



Harmful substances


Erucic acid can accumulate on the cardiac muscles, and when it is consumed in large amounts it can cause damage. Today its content in rapeseed oil is limited to maximally 5%.

Glucosinolates are sulphur compounds that, among other things, promote the formation of goitre and contribute to the bitter, biting taste of rapeseed oils. Meanwhile, some health-promoting effects are also presumed, such as a lowering of the cholesterol level.

Zero and double-zero rape varieties counteract the risks that accompany erucic acid and glusosinolates.


Presumed effect on health


When rapeseed oil is eaten, many essential fatty acids can be consumed, i.e. those that the body cannot produce itself but that perform vital functions and must be supplied through food. A good ratio of omega-3 to omega-6 fatty acids, as well as of saturated to unsaturated fatty acids, also prevails. An optimal fat intake in general has an influence on the development of cardiac diseases, arteriosclerosis and much more.


Form of consumption, use, processing, practical tips for preparation


We have already dealt intensively with rapeseed oil and its importance. But how is it extracted? We differentiate between two different oils:

* Cold-pressed rapeseed oil

The cleaned seeds are pressed and then filtered several times. As it is not otherwise treated, the colour and flavour of the oil are very intense. Cold-pressed rapeseed oil has a nutty aroma and is suited for the preparation of cold dishes such as salad dressings and dips.

* Fine rapeseed oil

Before the seeds are pressed, they are warmed to increase the yield during pressing. Then flavour, scent and aroma substances are removed so that the oil smells and tastes neutral. This oil is suited for stewing, frying and baking.

In addition to rapeseed oil for consumption, oil is produced that is added to soft soap, cleaning agents and cosmetics. Rape cake is a waste product of pressing for oil. It is processed and used as protein-rich animal fodder. Further, rape can be used to produce fuel (biodiesel).

Rape produces a great deal of nectar and pollen and is the most important plant for honey bees in Germany. Characteristic of rape honey are its mild and flowery aroma, its light colour and its creamy consistency. It is well-suited for sweetening tea and refining baked goods.

 

 

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