We use flour for a myriad of dishes and elaborations of bakery and pastry products, but what do we know about different flours? How is it obtained in each case? Which is the most convenient for each preparation? And for our health? In this article we will answer these questions and tell you everything you need to know about different flours
What is flour?
Flour is the fine powder that is obtained from ground cereals and other starchy foods. You can get different cereal flour. Although the most common is wheat flour, also made from other cereal flour such as rye, barley, oats, corn, rice ... and there are also other types of flours from other foods such as vegetables (peas, soybeans ), nuts, cassava, etc.
The flour may contain more or less whole grains, depending on whether more or less bran and germ are discarded. The proportion of whole grains that is used to obtain the flour is called the degree of extraction. When we speak of a 90% extraction degree, it would be a flour containing 90% of the whole cereal and 10% of bran and germ were discarded. Therefore, a whole meal would be a flour with 100% extraction.
What parts can we differentiate into a grain of cereal?
To get a clearer idea of what the whole cereal would look like, we'll see which parts we can differentiate into a grain of cereal.
In cereals we can differentiate 3 parts: bran, germ and endosperm.
Saved: it's the cereal cover. It is formed in turn by 2 parts:
Pericarp: is the outer layer and is formed by the epicarp, mesocarp and endocarp.
Cuticle: involves the seed and is formed by the layer of tesla and aleurone.
The bran is rich in B vitamins and minerals.
Endosperm: involves the germ or embryo and provides the nutrients needed for its development.
The endosperm contains a large amount of carbohydrates, especially starches and proteins, and to a lesser extent vitamins and minerals.
Germ: It is the part of the seed that germinates and will give rise to a new plant.
The germ contains high quality proteins, B vitamins, vitamin E, minerals and lipids that can be extracted in the form of vegetable oils.
Crushing or milling of wheat
Wheat milling consists of reducing the size of the grain through roller mills. First, the bran and germ are separated from the endosperm and then the latter is reduced until the flour is obtained. The purpose of milling is to maximize the yield of the flour with the minimum bran content.
The milling process consists of two stages of breaking and reduction, the grinding is done gradually, obtaining in each stage one part of flour and another of larger particles. Between the phase and the milling step, the milled product is screened and the flour is purified.
Crushing: The grain of wheat, after being cleaned and conditioned, is passed by the first set of rolls to be crushed.
Screening: The function of sifting or sifting is to separate the product into the three main fractions: bran, semolina and germ.
Purification: After crushing, the bran is discarded and the semolina is classified by thickness through sieves and purifiers.
Reduction: The purpose of the reduction is to grind the semolina and the purified semolina and turn them into flour. It reduces the semolina particles to a fineness of flour also removes some particles of bran and germ that can remain, this operation is carried out with a sieve. This process is performed several times until most of the withdrawable semolina is removed.
Grinding of common wheat: flour
Soft wheats are crushed and pressed into flour, which separates the bran and endosperm germ. The grain crushed by a sieving process, and then the pure endosperm particles, semolina and semolina are compressed and reduced in size until the obtained flour is sorted according to its size. This flour will be passed through sieves.
Grinding of hard wheats: semolina
In semolina mills do not crush the grain but do not cut layers to go progressively reducing its size until all the particles have the same size. By sifting the particles by their darker colored or weight are not suitable for the production of semolina are removed.
The flour has a yellow pigment composed of 95% of xanthophyll or its esters. Natural pigment bleaching wheat endosperm by oxidation occurs rapidly when the flour is exposed to air, the slower the mass of flour is exposed, and can be accelerated by chemical treatment using bleaching agents based mainly on chlorinated compounds.
Classification of flour types:
The most widely used classification in Europe, is based on the amount of gluten or proteins that flour has and, according to this, we can find:
Extra strong flour: It is characterized by having a high percentage of proteins (over 13%). It is obtained from durum wheat and is mainly used for the preparation of