Fig 1.
RP-HPLC chromatograms of the prolamin fractions.
(A) Wheat prolamins, (B) oat prolamins, (C) rye prolamins, unreduced, (D) rye prolamins, reduced with 1% (w/v) DTT, (E) barley prolamins, unreduced, (F) barley prolamins, reduced with 1% (w/v) DTT. AU, absorbance units at 210 nm, ω5, ω5-gliadins, ω1,2, ω1,2-gliadins, α, α-gliadins, γ, γ-gliadins, ave, avenins, ωs, ω-secalins, ωs+H, ω- and high-molecular-weight (HMW)-secalins, γ-75k, γ-75k-secalins, γ-40k, γ-40k-secalins, C, C-hordeins, γ/B, γ-hordeins and B-hordeins.
Fig 2.
RP-HPLC chromatograms of the glutelin fractions.
(A) Wheat glutelins, (B) rye glutelins, (C) barley glutelins, all reduced with 1% (w/v) DTT. AU, absorbance units at 210 nm, ωb, ωb-gliadins, HMW-GS, high-molecular-weight glutenin subunits, LMW-GS, low-molecular-weight glutenin subunits, HMW-Sec, HMW-secalins, γ-75k, γ-75k-secalins, γ-40k, γ-40k-secalins, D, D-hordeins, B/γ, B-hordeins and γ-hordeins.
Table 1.
Analytical characterization of the flours.
Contents of water, ash, crude protein (CP) and the Osborne fractions albumins/globulins (ALGL), prolamins and glutelins of wheat, rye, barley and oat flours (mixture of four cultivars each).
Table 2.
Analytical characterization of the isolated gluten protein types (GPT).
Proportions of each GPT in wheat, rye, barley and oat flours, protein content of each isolated GPT, their N-terminal sequence(s), molecular weight ranges (Mr) determined by LC-ESI-QTOF-MS and the Mr of the most appropriate reference sequence found in the NCBI database given with its specific accession.
Fig 3.
Overview of the preparative strategy.
This strategy allows the isolation of well-defined gluten protein fractions and types from wheat, rye, barley and oat flours. HMW-GS, high-molecular-weight glutenin subunits, LMW-GS, low-molecular-weight glutenin subunits.
Fig 4.
SDS-PAGE of flours, prolamin and glutelin fractions and isolated gluten protein types.
(A) Wheat. M: marker, 1: wheat flour, 2: wheat prolamin fraction, 3: ω5-gliadins, 4: ω1,2-gliadins, 5: α-gliadins, 6: γ-gliadins, 7: wheat glutelin fraction, 8: high-molecular-weight glutenin subunits (HMW-GS), 9: low-molecular-weight glutenin subunits (LMW-GS). (B) Rye. M: marker, 10: rye flour, 11: rye prolamin fraction, 12: ω-secalins, 13: γ-75k-secalins, 14: γ-40k-secalins, 15: rye glutelin fraction, 16: HMW-secalins. (C) Barley. M: marker, 17: barley flour, 18: barley prolamin fraction, 19: γ/B-hordeins, 20: C-hordeins, 21: barley glutelins, 22: B/γ-hordeins, 23: D-hordeins. (D) Oats. 24: oat prolamin fraction (avenins), 25: oat flour.
Fig 5.
Mass spectra of isolated (A) ω-secalins and (B) γ-hordeins. The spectra show the average of scans under the peak with retention times (A) 8.9 min and (B) 12.5 min from the respective base peak MS chromatograms after LC-ESI-QTOF-MS analysis of the isolated ω-secalins and γ-hordeins, respectively. The insets show the mass spectra simulated by maximum entropy deconvolution.