Separation of gliadins from wheat flour by capillary gel electrophoresis: optimal conditions

Introduction. Gliadin proteins are one of the gluten fractions. They are soluble in alcoholic solution and divided into four groups (α + β, γ, ω1.2, and ω5-gliadins). In this paper gliadins were extracted from wheat flour, and optimal conditions for their separation were determined. Study objects and methods. The separation was performed by capillary gel electrophoresis on Agilent apparatus, CE 7100 (a capillary with an inner diameter of 50 μm, a total length of 33 cm, and an effective length of 23.50 cm). In order to determine the optimal conditions, different solvent concentrations (50, 60, and 70% ethanol), capillary temperatures (20, 25, 30, 35, and 40°C), and electrode voltages (–14.5, –16.5, –17.5 and –18.5 kV) were applied. Migration time and relative concentration of each protein molecules within gliadin fractions in the electrophoregram were analysed using Agilent ChemStation Software. Results and discussion. The optimal conditions for gliadin separation were: solvent 70% (v/v) ethanol, capillary temperature of 25°C, and electrode voltage of –16.5 kV. Under these conditions, the total proteins were indetified as Xav = 23.50, including α + β gliadin fraction (Xav = 7.50 and relative concentration RC = 28.29%), γ-gliadins (Xav = 5.00, RC = 26.66%), ω1.2-gliadins (Xav = 4.33, RC = 14.93%), and ω5-gliadins (Xav = 6.67, RC = 30.98%). Conclusion. The results of the research can be of fundamental importance in the study of gluten proteins and the influence of technological procedures on their change and the possibility of reducing the allergic effect of gluten during processing.