Quantitation of the immunodominant 33-mer peptide from α-gliadin in wheat flours by liquid chromatography tandem mass spectrometry

Figure 1. MS/MS product ion mass spectra of the 33-mer peptide (a) and the isotopically labelled *33-mer (b). The four most abundant product ions (underlined) were used for identification. The most abundant product ion (y2) was used for quantitation.

Figure 2. Contents of 33-mer based on flour [μg/g] (a) and based on α-gliadins [mg/g] (b). 23 modern and 15 old common wheat cultivars (49 samples in total due to multiple harvest years (see Table 1)) and two spelt cultivars were analysed. Wheat cultivars registered prior to 1950 were designated as old. For abbreviations of the cultivars, see Table 1.

Figure 3. Linear Pearson correlations between contents of 33-mer and contents of α-gliadin (a), gliadin (b), gluten (c), and crude protein (d). 23 modern and 15 old common wheat (49 samples in total due to multiple harvest years (see Table 1)) and two spelt cultivars were analysed. Wheat cultivars registered prior to 1950 were designated as old.

Figure 4. Principal component analysis biplot of data for 33-mer, α-gliadin, gliadin, gluten, and crude protein contents. 23 modern and 15 old common wheat (49 samples in total due to multiple harvest years (see Table 1)) and two spelt cultivars were analysed. Wheat cultivars registered prior to 1950 were designated as old.