Pneumatic screen fractionation of barley and wheat flour for extraction of protein and carbohydrate fractions

Abstract

A technology has been developed for separating grains of wheat and barley into anatomical parts using pneumatic classification for maximum extraction of protein and carbohydrate fractions. To obtain a concentrated protein fraction, it is advisable to carry out centrifugal pneumosieve fractionation of crushed wheat flour, extracting small (up to 18 microns) light particles of protein and starch into one fraction, the yield of which should not exceed 15%. The final separation of protein and starch particles should be based on the difference in their density in a centrifugal-axial rotary pneumatic classifier. The highest content of starch differ fractions of barley flour, obtained by descending from sieves with holes of 40 and 30 microns (respectively 82,72% and 85,26%). In larger fractions, the starch content drops sharply (51,24% and 61,59%), which is explained by the presence of shell and protein particles in them. The protein content correlates with the ash content of the fractions, and the minimum ash content (0,97%) and protein content (7,51%) differ in the fraction obtained by passing a sieve with 63 μm holes and leaving a sieve with 40 μm holes. The maximum protein content (14,08%) is characterized by the finest fraction obtained by passing a sieve with a hole size of 30 μm. At the same time, the protein content in it is 1,9 times higher than in the fraction with a hole size of 30μm.