Changes in Secondary Protein Structures During Mixing Development of High Absorption (90%) Flour and Water Mixtures

Abstract

Cereal Chem. 83(2): [136][137][138][139][140][141][142] Wheat flour and water mixtures at 90% absorption (dry flour basis) prepared at various mixing times were examined using Fourier transform infrared (FT-IR) reflectance spectroscopy. Spectra were obtained using a horizontal attenuated total reflection (ATR) trough plate. The apparent amount of protein and starch on the surface of the dough varied with mixing time but this was likely due to the polyphasic nature of the substrate and the changing particle distributions as the batter matrix was , Wheat flour dough or batter may appear to be uniform and well mixed but actually it is multiphasic: starch, gluten, lipids, and water representing the principal phases. Furthermore, the form of these phases changes during periods of mixing that prepare them for separation or food uses. Microscopic changes begin with the instant formation of protein fibrils at first contact of water and flour particles (Bernardin and Kasarda I 973a,b; Amend and Belitz 1991). Slow mechanical development induces these fibrils to coalesce into fibrous bands or tendons and segregates the starch into clusters. When flooded with a displacing fluid, this open, sponge-like structure readily releases the entrained starch. This unmixed or separable state is evident in dough at 56-65% absorption and in batter at 90% absorption (Tipples and Kilborn 1975;Robertson and Cao 1998;Robertson et al 2000). Additional development disbands the protein into relatively line, uniformly distributed, and networked or webbed filaments that entrap the starch and gas bubbles formed when the dough is fermented and baked.The physical properties of hydrated wheat proteins are the result of covalent and noncovalent interactions of wheat gluten proteins. These interactions are altered by the repeated extension, tearing, and compression during mixing or development. Specific chemical effects include 1) disulfide bond disruption, 2) chain disentanglement and rupture, 3) disulfide-sulfhydryl interchange, 4) formation of dityrosine cross-links, 5) formation of new disulphide cross-links, 6) free radical interactions, and especially 6) reorientation leading to enhanced hydrogen bonding (Golstein 1957;

Exploring Functionality of Hard and Soft Wheat Flour Blends for Improved End‐Use Quality Prediction

“…Protein secondary structure is dependent on the secondary structure of the starting raw material (i.e., flour), system moisture content (i.e., flour, dough, batter, and bread), and system processing history (Wellner et al 2005;Li et al 2006;Robertson et al 2006). Protein secondary structure in the flour blend farinograph dough, GlutoPeak batter, and bread are shown in Table IV.…”

Protein Structural Features in Winter Wheat: Benchmarking Diversity in Ontario Hard and Soft Winter Wheat

“…FTIR spectroscopy has proven to be a useful tool in elucidating the nature of gluten structure and dynamics (Robertson et al 2006). Attenuated total reflectance FTIR spectroscopy has been used for the analysis of secondary structure of wheat gluten in dough under various conditions (Wellner et al 2005;Seabourn et al 2008;Sivam et al 2013;Jazaeri et al 2015) and has given a basis for a molecular explanation of the viscoelastic properties of the gluten network, which are essential to the breadmaking potential of dough (Bruun et al 2007).…”

Structural Modification of Gluten Proteins in Strong and Weak Wheat Dough as Affected by Mixing Temperature

“…This weakening occurs as a consequence of the conversion of relatively rigid elements of secondary structure (e.g., a-helices and b-sheets) into random coil structures that do not contribute to the strength of the overall gluten network (Robertson et al 2006;Bonomi et al 2014). This weakening occurs as a consequence of the conversion of relatively rigid elements of secondary structure (e.g., a-helices and b-sheets) into random coil structures that do not contribute to the strength of the overall gluten network (Robertson et al 2006;Bonomi et al 2014).…”