Because of the limitations of the current milling technology, the complete separation of wheat skin is difficult. So that the bran also contains a small amount of endosperm and germ. And the bran contains protein and starch and other components, with the quality of wheat and flour rate of high and low, so to maintain a certain quality of bran in the technology is very difficult. Flour production of bran is divided into coarse bran and fine bran.
Expanded Information:
Bran is a flake-like material. p>Bran is flaky, coarse bran and fine bran are fine crumbly, with varying degrees of coarseness and fineness, mainly due to the different proportions of water added.
Three are the flour process products of which the bran protein, high fiber, the highest price of bran, fine bran between the two.
Operational control of the production process:
① Reasonable moisture regulation. Moisture regulation is to ensure the integrity of the bran and bran, powder effective separation of the necessary measures. Through the moisture adjustment, can increase the toughness of the wheat cortex, reduce the strength of the endosperm, is conducive to grinding and bran powder separation, to ensure that a reasonable milling moisture to reduce the bran powder plays a vital role. In order to effectively guarantee the integrity of the bran, bran clean, into the grinding moisture must be appropriate.
Generally, the moisture of the net wheat into the mill, the production of ordinary flour for 13.5% to 14%; standard powder for 14% to 14.5%; special powder for 14.5% to 15 %; grade powder suitable for milling moisture should be about 15 %, when the powder road is shorter, it should be less than 15 %.
Particularly in winter, when the milling moisture exceeds 15 %, the material entering the brush bran machine is not only a large flow, but also contains heavy powder, the brush out of the bran white, muddy, not fresh, finger twisting with a wet feeling.
The wetting time is generally controlled in 16 ~ 30 h, when the raw material more hard wheat, raw material moisture is low, cold and dry climate, the wetting time should be 24 ~ 30 h; raw material for soft wheat, the wetting time should be 16 ~ 24 h. In actual production, with the hardness and grade of wheat, the grade of flour, the length of the process route, the climate and temperature changes, etc., to consider the optimal moisture and wetting time suitable for this plant. Optimal milling water and wetting time.
② Control the peeling rate of the skin milling system. The size of the bran flakes and the total flour rate is mainly determined by the skin milling system. In the general process, 1B, 2B scraping rate control in 1B: 18% ~ 30 %, 2B: 28% ~ 55 %, skin mill set up a longer route, take the lower value.
If the stripping rate is too low, it will result in low flour yield and endosperm particles sticking to the inner layer of the bran flakes; if the stripping rate is too high, it will result in excessive crushing of the bran flakes, and the quality of the slagging and the heart will also become inferior.
The production of 1B, 2B scraping rate should be measured at regular intervals, and at any time to check the 1B, 2B rolling distance changes, to avoid the phenomenon of one end of the rolling distance is tight and one end of the phenomenon is loose.
1B, 2B, 3B, 4B task is to scrape the bran. Operation should pay attention to: to scrape the net bran piece shall prevail, must not appear cut silk phenomenon, otherwise it will cause the bran piece is too broken, and will affect the quality of flour.
3 control flow balance and quality balance. Process balance emphasizes the homogeneous merger, grinding one by one, which is the key to maintain the integrity of the bran flakes. When considering the flow balance, 3B and 4B are divided into coarse and fine grinding, and the flow balance can be completely adjusted by the grading sieve. This not only improves the stripping rate, but also reduces the bran stars and keeps the bran flakes intact.
Maintain uniform feeding from 3B, as the bran flakes become lighter, many manufacturers release the material door when a large amount of material only go in the middle, gulp, bran flakes are very easy to break; close the small material door when the material upward, blocking the upper level of the equipment.In small and medium-sized factories, it is recommended to adjust the feed baffle to the tangential direction of the feed rollers, while gradually increasing the speed of the feed rollers, 2B for 200 r/min, 3B for 220 r/min, 4B for 250 r/min, the operation of the rolling distance is looser, the load is light, the bran piece is large, the production of bran is good.