Variation of protein molecular weight distribution parameters and their correlations with gluten and mixing characteristics for winter waxy wheat

Authors: Ohm, Jae-Bom; Dykes, Linda; Graybosch, Robert

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2018
Publication Date: 3/12/2019
Citation: Ohm, J., Dykes, L., Graybosch, R.A. 2019. Variation of protein molecular weight distribution parameters and their correlations with gluten and mixing characteristics for winter waxy wheat. Cereal Chemistry. 96:302-312. https://doi.org/10.1002/cche.10124.
DOI: https://doi.org/10.1002/cche.10124

Interpretive Summary: For the development of waxy (amylose-free) wheat cultivars which have improved gluten quality, information on the variation of protein composition would be highly useful. However, little data has been reported on protein composition for waxy wheat despite their possible significant influence on gluten quality. This research aimed to investigate variations of protein composition parameters and their associations with gluten quality traits in winter waxy wheat varieties. Specifically, this research investigated variations of size distribution for proteins in a fraction which were extractable by sodium dodecyl sulfate buffer solution and other proteins in unextractable fraction in winter waxy wheat. The polymeric proteins which are major proteins with the largest size in gluten were identified to be important components in screening of winter waxy wheat varieties for gluten quality. Waxy wheat varieties showed highly significant differences especially for polymeric proteins in extractable and unextractable fractions. The polymeric proteins were also observed to have highly significant influence on gluten quality. To be more specific, extractable polymeric proteins had negative associations and unextractable polymeric proteins had positive associations with gluten quality parameters which were mixograph peak time and gluten index. This information would be very helpful in screening winter waxy wheat varieties that have favorable protein compositions, and consequently, acceptable gluten quality in wheat breeding milling, baking and gluten production industry.

Technical Abstract: Little data has been reported on variation of protein MW distribution (MWD) parameters for waxy (amylose-free) wheat (Triticum aestivum L.) despite their possible significant effect on wheat quality traits. This research aimed to investigate variations of protein MWD parameters and their associations with gluten strength traits in winter waxy wheat genotypes. Winter waxy wheat genotypes varied significantly (P<0.001) for most protein MWD parameters including SDS extractable polymeric protein (EPP) and unextractable polymeric protein (UPP) fractions, which are major components of gluten proteins. The allelic variation of HMW glutenin subunits had significant influence on variations of EPP and UPP in waxy genotypes. Negative correlations for EPP and positive correlations for UPP were observed with mixograph peak time and gluten index for wheat genotypes. In particular, highly significant (P<0.001) correlations were observed between mixograph peak time and the proportion of EPP in total protein for waxy wheat genotypes. Overall, winter waxy wheat genotypes showed significant variations for EPP and UPP parameters, which were associated with variation of gluten strength. The results of this research indicate that there is a high probability of developing winter waxy wheat genotypes that have favorable protein compositions, and consequently, acceptable gluten quality.