Performance comparison of two media during starch-protein separation of chickpea flour using a hydrocyclone

Chickpea flour was suspended in isopropyl alcohol or deionized water at three concentrations and fractionated to the underflow (starch fraction) and the overflow (protein fraction) using a hydrocyclone. The separation using deionized water resulted in higher starch content in the underflow and higher protein content in the overflow than using isopropyl alcohol. Deionized water resulted in a greater starch separation efficiency (96.3-97.8%) and slightly lower protein separation efficiency (70.4-73.3%) than did isopropyl alcohol. The geometric mean diameter (GMD) of the overflow and underflow increased with a decrease in inlet pressure. The GMD of the underflow fraction in deionized water (26.27-31.28 μm) was greater than that in isopropyl alcohol (17.09-21.12 μm). In both media, the estimated centrifugal and drag forces increased with a decrease of inlet pressure. The centrifugal force applied to the particles in deionized water (1.32 x 10⁻⁶-1.67 x 10⁻⁶ N) was greater than that in isopropyl alcohol (0.54 x 10⁻⁶-0.76 x 10⁻⁶ N). Therefore, deionized water resulted in markedly higher starch separation efficiency. However, in isopropyl alcohol, a higher drag force was applied to the particles, and the protein separation efficiency was slightly greater than in deionized water. The separation of starch and protein from chickpea flour in suspension of isopropyl alcohol or deionized water using a hydrocyclone was investigated. Fractionation from the deionized water suspension resulted in higher starch content in the underflow and higher protein content in the overflow than from isopropyl alcohol. The method using deionized water resulted in higher starch separation efficiency; the separation using isopropyl alcohol resulted in slightly higher protein separation efficiency. The differences in the separation efficiencies of the two media were related to the variations in forces applied to the particles in the hydrocyclone. The magnitude of forces applied to the starch granules and protein particles was estimated.