CAPILLARY ELECTROPHORESIS OF WHEAT GLIADINS

Abstract

Identification of wheat varieties by their gliadin spectrum with acidic polyacrylamide gel electrophoresis has been in use for decades. Since the early 70s electrophoresis has been one of the most frequently used analytical methods for separation and characterisation of gluten proteins. Electrophoresis separates the analytes according to the difference in their charge distribution and/or Stoke's radii. Capillary electrophoresis (CE), the miniaturised instrumental version of electrophoresis, uses similar separation principle as the traditional technique, with several advantages. These are: high electric field, thus fast separation; low sample amount (nl); low buffer consumption (5 ml/day) thus low running costs; oncolumn detection, thus quantitative analysis; use of aqueous buffers thus no environmental wastes. Due to the several advantages capillary electrophoresis is gaining popularity in a number of fields, as opposed to the standard electrophoretic techniques. In our study a capillary zone electrophoretic method has been developed to separate the gliadin fraction of wheat proteins. The effect of the buffer composition on the resolution of the separation is shown. Various wheat types have been analysed for their gliadin spectra using both the traditional and the capillary electrophoretic method. Comparing the gliadin spectra obtained by means of the two methods, capillary electrophoresis seems to be a suitable alternative to the traditional method for identification / quality control of wheat species according to their gliadin spectra.