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How production of wholemeal flour can be simplified and optimized

12 April 20186 min reading

“The demand for production of wholemeal flour is increasing and millers may take an additional approach to their existing production line which is a flexible, efficient and cost-effective approach for industrial milling to meet the demand. This approach adds a parallel line where a combination of a discmill with other equipment such as micronizer or/ and a stone mill allows for the optimal production of high-quality organic wholemeal flour.”

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Mustafa ZİRAK - Marketing And Research, Engsko United Milling Systems

Whole grains have long been considered as a powerful health promoter. Nutrition-wise whole grains deliver important dietary components such as magnesium and dietary fiber, both of which are often low in Western diets. The demand for wholemeal foods has increased demand for wholemeal flour and food products that are wholly or partially whole grain. In the United States, the quantity of wholemeal flour (wheat) accounted in 2017 for about 5,2% of the total flour production. This can be compared to 2% wholemeal wheat flour production in 2002. In particle, article suggestions will be made on how to optimize production of wholemeal flour in an industrial capacity.

The purpose of milling grain mostly is to process the grains in mills with the aim to obtain the highest possible flour yield and high quality after completion of a large number of milling steps with intermediate sifting steps. The typical method for production of whole grain flour is on roller mills by way of recombination. In this multiple-stream process, different millstreams are separated by particle size and other predefined characteristics. Particles that are too large may be returned to be reground until they reach the correct size. Afterward, all the various millstreams are recombined to become whole grain flour that will have the proportions of bran, germ, and endosperm that are typical of the grains in the original batch.

Numerous milling/sifting steps may produce a comparatively white flour, which is the way roller mills are operating in, however, the disadvantage of a large number of steps is large machines and large space requirement, which means high investment costs. However, there are additional methods of production especially in relation to the production of wholemeal flour in which the miller should take into consideration.

One area of interest for a miller may concern a discmill which relates to a device and a method for processing grains, preferably but not limited to as the first step of a milling process. It is designed for a range of size-reduction applications, particularly in the cereal grain milling industry. The main characteristic of this unique grinding technology is very high productivity in relation to the physical size and energy consumption of the machine. Finished product granulation can be controlled over a wide range by the choice of corrugations on the grinding elements, selection of the peripheral speed of the rotating disc and, by adjusting the gap between the discs. Depending on the product and the desired granulation, the discmill has a capacity of up to 2.000 kg per hour.

A discmill is fast and operate more efficient with respect to flour yield than roller mills (based on the results from one milling pass or step). However, one milling step is rarely enough as the level of bran content in the flour will remain high. A further explanation will follow soon. A few other steps need to be taken in order to make finer flour. Nevertheless, the advantage obtained with a discmill lies in few milling/sifting steps required to obtain full yield as for production of wholemeal flour compared to a roller mill plant.

Normally, when grain is processed in one stage in a stone mill or in a micronizer, the process is so intense that it may cause damage to the gluten and the starch, and as a result, the whole grain flour may have less baking qualities. In order to maintain the baking qualities of whole grain flour, two goals must be met:

• To keep the baking qualities of gluten and starch. • To produce very fine particles of bran and germ. Both targets can be met by milling whole grain flour in multiple stages.

WHOLE GRAIN MILLING METHODS The additional approach which includes a discmill with the same or other combinations for production of wholemeal flour will be touched briefly and allows the miller to reach two objectives.

1. Flexibility as the miller can now add a separate line and allow for a complete organic section separated from the traditional flour milling section.

2. Low investment cost, in this way, it increases the whole milling capacity of the mill.

The goal is to reduce the granulation of bran and germ to very small particles by using micronizers, stone mills, discmills and adding the fine particles of bran and germ continuously to the flour collecting conveyors. It is important that the quality of gluten and starch remains good, and the fine particles of bran and germ do not interfere with the baking quality. These systems are designed in a multistage form. The following are some examples: 1. A combination of a roller mill and a discmill 2. A combination of two discmills 3. A combination of a discmill and a micronizer 4. A combination of a discmill and a stone mill

The discmill mentioned above is a modern “stone mill” in which the milling “stones” are made from a special metal, Wolfram Carbide, and are exceptionally hard-wearing alloy. The intensity of grind is determined by several factors including speed of rotation, element type, corrugation type, and dispositioning, as well as by the grinding gap, which can be adjusted while the machine is in operation. In above figure, four combinations are listed and in order to determine which combination is best we must examine what the goal is for the end product. For example, the discmill and micronizer combination along with the stone mill produces a high-quality wholemeal flour with a very fine particle size. The advantages also include low maintenance and high reliability. For example, the energy needed to produce very fine flour is estimated at approximately 80-90 kW per ton for the discmill and micronizer combination. The combination of a discmill and a stone mill is also excellent for the production of fine and high-quality wholemeal flour. The differences of the four combinations rely on capacity and degree of fineness of the end product.

To sum it up: The demand for production of wholemeal flour is increasing and millers may take an additional approach to their existing production line which is a flexible, efficient and cost-effective approach for industrial milling to meet the demand. This approach adds a parallel line where a combination of a discmill with other equipment such as micronizer or/ and a stone mill allows for the optimal production of high-quality organic wholemeal flour.

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