The dissertation is dedicated to the development of recommendations for improving the technology of production the corn groats by scientific and practical substantiation of separate stages of preparation and processing of corn grain.
Samples of corn grain processed at Ukrainian enterprises in 2016-2018 were analyzed; intermediates and finished corn products obtained in industrial and laboratory conditions, as well as parameters and modes of stages: cleaning and corn grain intake, tempering of corn grain, degermination of corn grain and tempering of corn groats in the production of small corn flakes.
It is determined that the number of sown areas in Ukraine allocated for corn in 2016-2018 reached 2.8-3.5 million hectares. The bulk of corn was sown in the central and northern regions, the minimum area of land sown for corn was in the southern and eastern regions. The varietal composition of corn grain, which is distributed on the territory of Ukraine, has been established. It is shown that among the high number of varieties included in the state register of plant varieties in 2016-2018, half of the land for corn was sown only with 25-30 varieties. Based on statistical analysis, the predominant part in the typical composition of corn grain that grown in Ukraine was confirmed, dent type – 57.8-61.3 % and to a lesser extent semi-dent type – 24.3-26.2 %. The part of more technological flint corn is only 9.6-14.4 %, consequently when justifying the modes of processing corn into cereals, more attention should be paid to the modes of processing corn grain dent type or semi-dent type. It is determined that the grain of corn entering for processing, after its harvesting and post-harvest processing already has a certain number of cracked grains. The largest stress crack of corn grain is characteristic of flint corn – 50-89 % and semi-dent corn – 32-84 %; in dent corn stress crack is less – 25-73 %.
Technological indicators of corn grain quality are established: specific weight of grains – 235-310 g; bulk density – 790-815 g/l. The chemical composition of corn grain processed in 2016-2018 was studied: protein content – 8.6-11.3 %; fat content – 5.8 to 7.6 %; starch content – 67.2 to 70.4 %; ash content – 2.20 to 2.41. It is established that according to technological properties, chemical composition and indicators the studied samples of corn grain had the necessary quality indicators for their further use as raw materials for the production of cereals and flakes.
The regularity of the change in the fractions yield and the germ content when changing the regimes of the degerminator is established. With increasing gap on the degerminator (decrease in total extraction from 34.9 to 12.4 % – for dent corn; from 27.3 to 13.6 % – for flint corn), the yield of large fractions of intermediate products in the overtail of the degerminator increases from 65.1 to 87.6 % for dent corn, from 72.7 to 86.4 % – for flint corn, but in the overtail of the degerminator remains a large number of germ – 25.9 % for dent corn and 19.2 % for flint corn, respectively. It is recommended to control the quality of the degerminator overtail product: the fat content should not exceed 2.0-2.2 % – in the production of long-term storage products and for baby food not more than 2.3-2.5 % – in the production of conventional corn products. It is proposed to use the rate of total extraction for operational control, which can be determined by sieving a 100-gram portion of the overtail product on a sieve Ø 3.0. To ensure the fat content in cereals at the level of 0.6-0.8 and 0.8-1.0 %, the total extraction in the processing of dent-type corn should be in the range of 28-33 and 23-28 %, respectively, for flint corn – 20-24 and 16-20 %, respectively.
It is determined that in the production of flakes in semi-production conditions it is technologically expedient to use moistening of cereals stage before sending them for steaming in the production of small corn flakes. The optimal modes for this method of tempering are: the humidity of cereals before steaming – 17±0.2 %, steaming time – 7.5-10 minutes, the duration of tempering – 30-40 minutes.
