Fast wheat variety classification by capillary gel electrophoresis-on-a-chip after single-step one-grain high molecular weight glutenin extraction

Abstract

Wheat variety identification based on one-step single-grain wheat extraction and fast capillary gel electrophoresis-on-a-chip (CGE-on-a-chip) analyses was evaluated for 15 different wheat varieties grown in Austria. The results of the capillary-based separation system were compared to the internationally accepted method from the International Union for the Protection of New Varieties of Plants which is based on time-consuming sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Comparable protein patterns were observed making the CGE-on-a-chip system a promising tool for high-throughput analysis in food control. For the development of a robust method protein extraction, shelf life of wheat extracts and the instrument's variability were evaluated. It turned out that a one-step single-grain wheat extraction allowed the sample to be stored at 4 °C for up to 4 weeks without losing any valuable protein information. Furthermore, the technical variation of the whole method is very low making the biological variation of the selected wheat grains the only uncertain factor. Additionally, two unsupervised statistical methods (hierarchical cluster analysis and principal component analysis) were used for variety identification. Identification was successful for a reduced data set of 14 samples from five different wheat varieties making the combination of CGE-on-a-chip analysis of one-step single-grain extraction in combination with automatic data evaluation a promising tool for fast wheat differentiation (within a day).