Location: Cereal Crops ResearchTitle: Molecular weight distribution of flour proteins in intermediate wheatgrass (Thinopyrum intermedium): Impact on end-use quality parameters
|Gajadeera, Chathurada - University Of Minnesota|
|Whitney, Kristin - North Dakota State University|
|Rahardjo, Citra - University Of Minnesota|
|Simsek, Senay - North Dakota State University|
|Ismail, Baraem - University Of Minnesota|
Submitted to: Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 5/24/2016
Publication Date: 7/16/2016
Citation: Gajadeera, C., Ohm, J.-B., Whitney, K., Rahardjo, C., Simsek, S., Ismail, B. 2016. Molecular weight distribution of flour proteins in intermediate wheatgrass (Thinopyrum intermedium): Impact on end-use quality parameters [abstract]. Institute of Food Technologists, July 16-19, 2016, Chicago, IL.
Technical Abstract: Thinopyrum intermedium, commonly known as intermediate wheatgrass (IWG) is a perennial crop shown to have both environmental and nutritional benefits. We have previously shown that in comparison to wheat controls, IWG lines had higher protein and dietary fiber contents. However, a deficiency in high molecular weight glutenins (HMWG), an important protein component responsible for dough strength, was seen for all IWG samples. Therefore, the objective of this study was to better understand the protein distribution of IWG lines and its relationship to bread-making quality parameters. Sixteen IWG lines along with one-bulk IWG sample and two wheat controls were analyzed for molecular weight distribution of flour proteins using size exclusion chromatography and subsequent evaluation of bread-making quality. Two-dimensional gel electrophoresis followed by MALDI-TOF and liquid chromatography coupled with tandem mass spectrometry were performed on extracted gluten from bulk IWG sample and hard red winter wheat to determine molecular weight and identify the HMWG subunits. Dough rheological measurements were performed using farinograph and Kieffer following standard procedures. In contrast to wheat controls, IWG samples had lower percentage of SDS-unextractable high molecular weight polymeric proteins (uHMWPP). This fraction of proteins in IWG lines showed a significant and a positive correlation with farinograph stability and Kieffer-resistance to extension, but lower than that of wheat controls. Relative quantity of soluble albumins and globulins were higher in IWG samples than that of wheat. The protein distribution and molecular weights of HMWG subunits in the IWG bulk sample were considerably different from HRWW. These findings suggest that lower uHMWPP content in IWG samples results in poor dough rheology due to lack of proper gluten network formation. The difference in protein distribution coupled with higher fiber content in IWG may negatively affect the protein functionality and end-product quality. Investigating the effect of fiber content on dough rheology may help identify ways to utilize of IWG grain in commercial applications.