Location: Cereal Crops ResearchTitle: Variation and correlation of protein molecular weight distribution and semolina quality parameters for durum genotypes grown in North Dakota
|MANTHEY, FRANK - North Dakota State University|
|ELIAS, ELIAS - North Dakota State University|
Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2017
Publication Date: 7/9/2017
Publication URL: http://handle.nal.usda.gov/10113/5700911
Citation: Ohm, J.-B., Manthey, F., Elias, E.M. 2017. Variation and correlation of protein molecular weight distribution and semolina quality parameters for durum genotypes grown in North Dakota. Cereal Chemistry. 94(4):780-788.
Interpretive Summary: This research assessed the associations between size distribution of protein molecules and quality characteristics for durum semolina samples. Semolina samples were obtained from thirteen durum genotypes grown at seven locations for two years in North Dakota. Proteins in semolina that were extractable and unextractable by sodium dodecyl sulfate (SDS) solution were individually analyzed for size distribution using an analytical method called size exclusion HPLC. The SDS extractable and unextractable gluten proteins associated differently with semolina gluten strength characteristics. While SDS extractable gluten proteins had negative influence on gluten strength, large protein molecules in SDS unextractable fraction contributed to increasing gluten strength. Spaghetti cooking characteristics were greatly associated with total quantity of gluten proteins. Specifically, total quantity of gluten proteins in both SDS extractable and unextractable fractions had a strong positive effect on cooked spaghetti firmness. However, the percentage of SDS extractable gliadins which are small size gluten proteins was found to have a negative association with cooked spaghetti firmness, while the percentage of the large protein molecules in SDS unextractable fraction had a positive effect. Those two protein size parameters are highly expected to help evaluation of durum wheat genotypes for gluten strength and spaghetti cooking characteristics.
Technical Abstract: This research assessed the associations between protein molecular weight distribution (MWD) and quality characteristics for durum semolina samples that were obtained from thirteen durum genotypes grown at seven locations for two years in North Dakota. Sodium dodecyl sulfate (SDS) extractable and unextractable proteins in semolina were analyzed for MWD by size exclusion HPLC. The SDS extractable and unextractable gluten proteins correlated differently with semolina gluten strength characteristics. Both gluten index and mixograph classification showed positive correlations with SDS unextractable polymeric proteins and negative correlations with extractable gliadins and polymeric proteins. Quantitative variations of protein MWD parameters greatly influenced spaghetti cooking characteristics. Specifically, cooked spaghetti firmness (CSF) had high and positive correlations with quantitative variations of gluten protein in both SDS extractable and unextractable fractions. Variation in those protein fractions were also highly influenced by growing environments. However, a qualitative MWD parameter, percentage of the SDS extractable gliadins in total protein had a negative genotypic correlation with CSF while percentage of the SDS unextractable polymeric proteins had a positive correlation. Those two MWD parameters showed significant (P<0.05) variations for genotypes and they also improved significantly accuracy of multiple regression model of CSF when combined with protein content.