What is the corn starch production process?

Corn is stripped from the corn kernels on the ears of corn, and the corn kernels contain 12~16% moisture, 70~72% starch, 8~11% protein, 4~6% fat, 1.2~1.6% ash, and 5~7% fiber.

Corn starch is a product made from corn kernel as raw material, through sulfite soaking, crushing and sieving, grinding, separating and washing, dehydration and drying.

The product is mainly used in medicine, food, chemical industry, textile and other industries, can produce caramel, high maltose syrup, glucose, modified starch, soluble starch, cyclodextrin, acidic starch, oxidized starch, high fructose syrup; can be used as raw materials for the production of enzyme preparations, monosodium glutamate, amino acids, and antibiotics, such as the raw material for fermentation.

In recent years, with the development of production in all walks of life, corn starch with a wide range of uses, excellent performance, moderate price to the market, doubly favored by the market.

Corn starch production process

Operation Points

2.1 Selection of raw materials

Select the corn as raw material which is free from impurities, full grains, moth and mold.

2.2 Preparation of sulfurous acid

Prepare sulfur dioxide by burning sulfur, then dissolve it in water and prepare sulfurous acid, the newly prepared sulfurous acid solution should contain S02 0.25~0.3%.

2.3 Soaking and crushing of corn

Countercurrent method or diffusion method of soaking, the newly prepared sulfite solution pumped into a group of soaking tanks to soak corn, according to the soaking liquid countercurrent inverted tanks, the longest soaking time, in turn, to the shorter soaking time to move (inverted tanks), with this method, the concentration of leachate can be up to 7-9%, leachate further concentration of steam consumed less than the static method.

After soaking corn using the second crushing, separation process, so that the germ all separated from the endosperm. Soaked corn germ contains about 60% water, has great elasticity, at the same time the germ, corn husk and endosperm linkage between the weakening of the endosperm of corn, the endosperm of corn protein and starch linkage between the weakening of the endosperm of corn, crushing is easy to be separated from the corn kernel. In addition, the amylopectin portion of the endosperm is ground into crushed grains during crushing, from which about 25% of the starch can be released.

2.4 Separation and washing of germ

After primary crushing, most of the germ and endosperm are separated from the corn kernel, and the germ is separated through the floating tank, and then into the secondary crushing, after two crushing and separation, the germ is all separated.

The separated germ is sprayed by continuous water on the vibrating screen to wash away the adhered starch milk and gluten on the surface of the germ, and then it is preliminarily dewatered by centrifuge to the moisture content less than 36%.

2.5 Grinding of slurry

After crushing and separating the endosperm, the crushed slurry consisting of starch granules, gluten, seed coat, crushed endosperm grains containing a large amount of starch, etc., needs to be finely ground by the primary and secondary impact mills with the aim of making the endosperm finer in particle size and at the same time releasing the starch associated with proteins and cellulose at the maximum extent, so as to create conditions for the separation of the next step of the process.

2.6 Sieving and washing of dregs

The suspension formed after grinding of the pulp contains free starch, fine particles of gluten and cellulose (fine and coarse dregs). Separation of the coarse and fine dregs from the starch suspension is carried out using a seven-stage pressure curved sieve, and the dregs undergo a six-stage countercurrent wash to wash away the starch adhering to them.

2.7 Separation of starch from gluten

The separation of starch and gluten is carried out in the disk centrifuge. Since the particle size and specific gravity of starch particles are larger than that of protein particles, its settling speed in the suspension is faster than that of protein particles, and the centrifuge can be used to separate starch and protein with high efficiency.

2.8 Washing and mechanical dehydration of starch

In order to remove the soluble and insoluble protein, reduce the acidity of starch and improve the concentration of suspension, ten-stage cyclone countercurrent washing is used. After washing, the starch is mechanically dehydrated by horizontal scraper centrifuge, and the water content of wet starch is 38~40%.

2.9 Drying of starch

Adopting airflow drying, the starch is fed into the fluffer by the screw conveyor according to the output requirement (depending on the moisture content of the finished starch), and the mechanically dewatered wet starch is fed into the airflow drying system in the fluffer, and at the same time, the pre-purified and heated hot air up to 140℃ is fed in for drying.

Production of by-products

3.1 Production of corn oil

The washed germ is centrifugally dehydrated, baked and dried in a rotary drum dryer with a heating furnace to a moisture content of 1~1.5%, and then pressed by a screw press, the oil pressed out of the oil storage tank, so that the suspended impurities in the oil naturally settle, filtered by plate and frame filter press to remove impurities, and then get the gross corn oil, which contains more than 85% of the unsaturated fats. Corn oil can also be further processed into margarine, shortening and so on.

3.2 Protein powder production

Separated from the butterfly centrifuge slurry, sent to the storage tank in the natural settlement, pumping up the clear liquid, 5% concentration of slurry filtered by the plate and frame filter press to the non-drip, the filter cake into the pulverizer in the crushing, and then into the air dryer to dry to the moisture content of less than 14% can be.

3.3 Production of leachate (corn syrup)

In the process of corn soaking, soluble dry matter from the corn kernels transferred to the leaching solution, with the diffusion method of soaking in the leachate dry matter content of up to 8 ~ 9.5%, the leachate contains a large number of proteins, soluble carbohydrates, ash, oil, starch, lactic acid and other substances.

The leachate is concentrated to 48~50% of dry matter by vacuum concentration method, and corn syrup is obtained, and the by-products can be used for the production of antibiotics, yeast and alcohol.

Corn starch product quality standard

and production test results

Production test on corn starch products, the results are shown in the table below, the average yield of 59.8%.

4.1 Sensory index of raw materials

4.2 Physical and chemical indicators

4.3 Health indicators

Conclusion

Using this process for production test, the average starch rate is 59.8%, and the product quality reaches the standard of superior grade. This process not only produces the main product corn starch, but also produces three kinds of by-products, which can improve the utilization rate of raw materials, reduce energy consumption and environmental pollution, lower production costs, and achieve the purpose of comprehensive utilization.