Degree of grinding
The degree of grinding (or the yield ) describes how much flour was made from 100 kg of grain during grain processing in the mill . In a modern mill there are yield computers that continuously monitor production. When producing light-colored flours, the miller's goal is to separate as many endosperm cells as possible from the inside of the grain from the shell particles ( bran ).
Composition of a cereal grain in percent (here wheat ):
| parameter | full grain | Bowl | Endosperm | Seedling |
|---|---|---|---|---|
| Share of whole grain | 100 | 17th | 80 | 3 |
| Starch / carbohydrates | 82 | 61 | 88 | 56 |
| protein | 12 | 11 | 10 | 26th |
| Fats | 2 | 5 | 1 | 10 |
| Fiber | 2 | 14th | 0.5 | 3 |
| Minerals | 1.5 | 9 | 0.5 | 5 |
Remarks:
- In the outer layers of the grain, defense substances against predators (antinutrients) such as z. B. phytin , and impurities such. B. pesticides , heavy metals and mold toxins .
- The seedling is rich in proteins and carbohydrates, trace elements and vitamins of the B group. It also contains oils, just as the outer layers (skin) of the grain contain oils. After grinding, these oils become rancid relatively quickly when they come into contact with atmospheric oxygen, which is why flours with higher proportions of surface layer and seedling have a reduced shelf life.
For wheat , the following statements can be made as approximate reference points about the degree of milling and the corresponding flour names in Germany and Switzerland:
- Yield approx. 50-60%: German DIN designation: Type 405 , or CH (Swiss) designation: white flour
- Yield approx. 75%: German designation: Type 550 , or CH designation: semi-white flour
- Yield approx. 83%: German designation: Type 1050 , or CH designation: Ruchmehl
- Yield min. 98%: German designation: wholemeal flour (wholemeal products are not DIN- typed), or CH designation: wholemeal flour .
As wholemeal flour , the milled whole cereal grain is referred to as a mineral content of 2% or more. It must contain all the components of the purified wheat kernels, including the sprout . The outer skin of the fruit may be removed from the grains prior to grinding ( Steinmetz process / Steinmetz flour ). If the seedling has been removed beforehand, the miller speaks of " breadcrumbs " - DIN type 1700 for wheat and DIN type 1800 for rye . Baked meals are of course no longer whole grain products. Whole wheat flour is more difficult to process when baking (relatively little glue ). For this reason it is often mixed with Type 550.
Individual evidence
- ↑ JA Gwirtz, MR Willyard, KL McFall: Future of Flour: Wheat: More than just a Plant , muehlenchemie.de, accessed on November 19, 2016