Reversed-phase high-performance liquid chromatography of durum wheat gliadins: Relationships to durum wheat quality

Abstract

Durum wheat gliadins have been analyzed by RP-HPLC (reversed-phase high-performance liquid chromatography) for the first time. Gliadins extracted from each particular durum variety were resolved to give a complex chromatographic pattern that was unique to that variety. However, four chromatographic fractions, which were eluted under hydrophobic conditions (45·2, 45·6, 47·4 and 49·1% acetonitrile, respectively), could be used to classify durum varieties into two groups. Proteins in these fractions were purified by preparative RP-HPLC and analyzed by aluminium lactate-polyacrylamide gel electrophoresis (AL—PAGE), which indicated that two of these fractions contained gliadin bands 45 or 42 that have been shown previously to be correlated closely with gluten strength and weakness, respectively. Therefore, RP—HPLC can be used also to screen for gluten quality characteristics in durum varieties in a way analogous to that in which electrophoresis may be used. A rapid, highly-automated RP-HPLC analytical procedure was developed to screen for durum varieties with unacceptably weak gluten characteristics. Each determination takes less than 10 min, permitting approximately 200 analyses per 24 h. Because of its convenience and rapidity, RP-HPLC of durum wheats has considerable potential as an alternative to electrophoresis as an analytical tool for screening for gluten traits when large numbers of samples must be screened, as in early generation of wheat breeding.