|Quantification of peptides causing celiac disease in historical and modern hard red spring wheat cultivars|
B. DUPUIS (1), R. Bacala (1), B. Fu (1), D. Hatcher (1) (1) Canadian Grain Commission, Winnipeg, MB, Canada.
Wheat gluten imparts “unique” functional characteristics to dough which allow it to make bread. While High Molecular Weight Glutenin Subunits (HMW-GS) are partially responsible for gluten strength Canadian wheat varieties in the premium CWRS class have the same HMW-GS composition yet there is a wide range in their gluten strength. Low molecular weight subunits (LMW-GS) play a key role in gluten polymer size and strength yet limited investigation of Canadian wheat has been done. Four varieties of CWRS, Glenn, Viewfield, Carberry and Unity, representing a wide range in gluten strength were grown at six sites across the western prairies. LMW-GS were prepared via sequential extraction, precipitation, alkylated with 4-vinyl pyridine and analyzed of an ESI-ToF mass spectrometer to characterize differences in these key proteins relative to gluten strength due to different growing environments. Molecular weight accuracy was 6 Da or an RSD of 0.02% with a precision RSD of 0.0013%. The strongest varieties; Glenn, Viewfield and Carberry displayed similar LMW-GS protein patterns above 42,000 Da while the weakest, Unity, exhibited no proteins in this range. The two strongest varieties, Glenn and Viewfield shared a common, most abundant, protein of 42,927 Da however Carberry’s most abundant protein exhibited a mass of 33,553 Da. Unity, the weakest, had its most abundant protein at 40,343 Da. Only 3 LMWs were present in all varieties at all sites: 40,587, 33,278, and 32,444 Da. The 3 strongest varieties only had 8 proteins in common above 30,000 Da, with 6 of these above 40,000 Da, suggesting they are serine-B-type LMWs. All varieties exhibited the presence/absence of different proteins depending upon their growing environment. Only 3 proteins, found in all 4 varieties, displayed absence/presence of the protein due to growing environment; 40,424, 33,296 and 32,382 Da.