Technological improvements of grain preparation for milling in small enterprises

Introduction. In small enterprises with simplified technological process of graded milling, preparations, which involve cleaning, peeling and moistening grain, play an essential role for ensuaring high quality of graded flour. Modern equipment for the low-productive mills implies only dry cleaning of grains in an abrasive machine with their further cold conditioning. The equipment designed for graded milling with deep multiple cleaning, washing and hydrothermal treatment is not possible. It significantly increases the cost of flour. The aim of the study is to increase both qualitative and quantitative indicators of graded flour in small enterprises through peeling and drying of grains before milling. Materials and Methods. The quality analyses of grain processing according to such indicators as ash content (whiteness), moisture, quantity of fractured grains were carried out according to State Standards of the Russian Federation and the methods established in science and practice. The degree of peeling was determined by the whiteness indicator with a photoelectric whitener SKIB-M (GOST 26361-2013 “Flour. Test method for whiteness”). Grain moisture was determined according to GOST 13586.5-2015 by the drying cabinet DEC-3M (drying electrical cabinet, model type 3M). The number of fractured grains was determined according to GOST 30483-97. Results. The research result revealed the dependence of grain processing on the technical aids. А combined peeling-drying machine was developed on this principle. The authors have developed rational operations of grain processing, which increase the whiteness of the received flour on average 4-7 conventional units. The standard instrument for whiteness definition has been studied and set. According to the given results optimal operating parameters for grain processing before milling have been developed: machine productivity (Q = 700 kg/h); the period of grain processing (t = 72 s.); optimum moisture content (from the point of view of obtained flour whiteness) of grains received for milling (W = 14 %); radiant power (P = 1 000 W). Conclusions. The research proved the fact that peeling of grains is one of the most effective ways of increasing the grade of end products of small enterprises with simplified technological process of graded milling. The efficiency of peeling seeds of wheat with humidity higher than 16 % decreases that speaks for the need to dry grains. The authors of the article introduce the equipment and technology for grain processing before graded milling, which provide grain peeling and, if necessary, drying. The operating parameters of the peeling-drying machine for preparation of grains for milling have been determined. The developed technology provide, if necessary, drying the remoistened grain to necessary standards that gives the chance to produce high-quality flour from the grains processed hydrothermally without processing moisture conditions required. The machine productivity in the mode of drying should be connected with the power of microwave infrared radiation, and its time and power should be limited to a maximum permissible grain temperature, which does not exceed 60 ºС.