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Molecular Weight Distribution of Proteins in Hard Red Spring Wheat: Relationship to Quality Parameters and Intrasample Uniformity

¹USDA-ARS-RRVARC-NCSL, Cereal Crops Research Unit, Hard Spring & Durum Wheat Quality Laboratory, Fargo ND. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable. ²Corresponding author. Phone: 701-239-1414. Fax: 701-239-1377. E-mail address: jae.ohm@ars.usda.gov ³Department of Plant Sciences, North Dakota State University, Fargo, ND. ⁴USDA-ARS-CGAHR, Grain Quality & Structure Research Unit, Hard Winter Wheat Quality Laboratory, Manhattan, KS. ⁵USDA-ARS-CGAHR, Engineering & Wind Erosion Research Unit, Manhattan, KS.

Molecular weight distribution (MWD) of proteins extracted from hard red spring wheat was analyzed by size-exclusion HPLC to investigate associations with wheat and breadmaking quality characteristics. Certain protein fractions were related to associations between wheat and breadmaking parameters, specifically when effect of quantitative variation of protein on those parameters was statistically eliminated by partial correlation analysis. SDS-unextractable high molecular weight polymeric proteins had positive partial correlations with percent vitreous kernel content and breadmaking parameters, including mix time and bread loaf volume. SDS-extractable protein fractions that were eluted before the primary gliadin peak had positive partial correlations with kernel hardness and water absorption parameters. The proportion of main gliadin fractions in total protein had a negative partial correlation with bread loaf volume and positive correlations with kernel hardness and water absorption parameters. Intrasample uniformity in protein MWD and kernel characteristics was estimated from three kernel subsamples that were separated according to single kernel protein content within individual wheat samples by a single-kernel near-infrared sorter. Wheat subsamples were significantly different in protein MWD. Intrasample uniformity in protein MWD did not differ greatly among wheat samples.