Physicochemical Characteristics of Pin-milled and Turbo-milled Chickpeas

Abstract

The effect of pin-milling and turbo-milling on particle size distribution and geometric mean diameter of chickpea flour was determined. The form factor and starch granule diameter of both samples were also calculated. Both samples were divided into six granulometric fractions with a sieving classifier using a range of mesh opening from 44 to 425 µm, which include five sieves and one pan. The starch and protein contents of the initially obtained flour and each fraction were determined. A major proportion of particles of both samples had a geometric mean diameter of 326 µm. Pin-milled flour had a geometric mean diameter of 270.7 µm at a moisture content of 8.29% (w.b.). Turbo-milled flour had a geometric mean diameter of 268.5 µm at 8.52% (w.b.) moisture content. There was no significant difference between pin-milled and turbo-milled flours in terms of geometric mean diameter of particles and average diameter of starch granules. There was no considerable difference between the starch granule size of the six fractions and the initially obtained flour of both samples. The averages of form factor and starch granule diameters in pin-milled and turbo-milled flours were determined using scanning electron microscope (SEM) images and Matrox Inspector software. The average form factor and starch granules diameters in pin-milled flour were 0.77 and 15.78 µm, respectively, while those of turbo-milled flour were 0.69 and 15.70 µm, respectively.