Author
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Bietz, Jerold |
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Lookhart, George |
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Submitted to: Journal of Food Science and Technology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/17/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Recent studies have shown that a new analytical method, capillary electrophoresis (CE), gives excellent and useful separations of wheat proteins. Wheat varieties can be identified and results can be related to quality. For such a method to become widely used, however, it must give the same results in different laboratories. To test this, we extracted gliadin proteins from several wheat varieties and analyzed them in two laboratories using the same methods. Excellent and comparable separations were achieved at both locations. We found, however, that differences between batches of commercial buffers could cause results to vary. Homemade buffers, carefully prepared, give best results. Our results show that CE is a rapid, reliable, and reproducible method for wheat varietal identification and is a useful alternative to other methods. Technical Abstract: Capillary electrophoresis (CE) is a rapid automated method for wheat protein analysis. It is sensitive, reproducible, and gives high-resolution separations of gliadins, differentiating most genotypes. Optimal CE conditions have not yet been established, however, nor methods compared between laboratories. We, therefore, analyzed 30% ethanol-soluble gliadins from several wheat varieties by two methods in two laboratories using Beckman 2100 P/ACE systems. Both methods used a commercial 0.1M phosphate buffer, pH 2.5, containing a linear hydrophilic polymer, and 27 cm uncoated silica capillary columns (20 cm inlet to detector). One method used a 50 um i.d. capillary at 7 kV; separations required 30-40 min. The other method used a 20 um capillary at 22 kV; separations took about 10 min. Within each laboratory, both methods gave excellent separations, with comparable selectivity and resolution. Results from the two laboratories for short analyses were equivalent, with elution times for corresponding peaks differing by an average of +/ 0.030 min. For the longer separations, resolution and elution times were also equivalent at both laboratories. Elution times and operating currents varied slightly for different batches of buffer, however, showing the need for careful standardization of buffer composition. These results show that CE is a rapid, reliable, and reproducible method for wheat varietal identification and a useful alternative or replacement to slab gel electrophoresis or high-performance liquid chromatography. |
