|QUAYSON, E - University Of Minnesota|
|MARTI, A - University Of Milan|
|MARENGO, M - University Of Milan|
|BONOMI, F - University Of Milan|
|SEETHARAMAN, KOUSHIK - University Of Minnesota|
|IAMETTI, STEFANIA - University Of Milan|
Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2018
Publication Date: 3/1/2018
Citation: Quayson, E.T., Marti, A., Morris, C.F., Marengo, M., Bonomi, F., Seetharaman, K., Iametti, S. 2018. Structural consequences of the interaction of puroindolines with gluten proteins. Food Chemistry. 253:255-261.
Interpretive Summary: The present study highlighted that puroindolines have an impact on gluten protein interactions in flour. Puroindolines enhanced gluten protein aggregation, resulting in decreased SDS extractability, decreased thiols accessibility and increased LMW-to-HMW ratio in SDS-extractable fractions. Puroindolines also affect exposure/accessibility of amino acid side chains that may be considered as “reporters” of protein structural organization. This was determined by flour aqueous suspensions in the absence of significant mechanical deformation of the involved proteins, suggesting that these interactions occur in the grain and in the flour prior to mixing. From a more practical standpoint, we are currently taking advantage of recent methodological developments to investigate how proteins in the different flours considered in this study behave when these flours are mixed into dough. This should provide insights on the possible impact of puroindolines on the structural modifications accompanying formation of a gluten proteins.
Technical Abstract: The effect of puroindolines (PINs) on structural characteristics of gluten proteins was investigated in Triticum turgidum ssp. durum (cv. Svevo) and Triticum aestivum (cv. Alpowa) and from their respective derivatives in which PIN genes were expressed (Soft Svevo) or the distal end of the short arm of chromosome 5D was deleted (Hard Alpowa). PINs presence altered the amount and profile of cold-SDS extractable proteins, and the accessibility of protein thiols to specific reagents. PINs presence also resulted in a more difficult salvation of gluten proteins, as detected by tryptophan fluorescence measurements carried out on minimally mixed flour/water mixtures. On this basis, we propose that PINs and gluten proteins are interacting in the grain/flour prior to mixing. Hydrophobic interactions between PINs and some of the gluten proteins may prevent interactions among gluten proteins in the grain itself, thus providing a mechanistic rationale for the effects of PINs on kernel hardness.