title: Determination of secondary structural changes in gluten proteins during mixing using Fourier transform horizontal attenuated total reflectance spectroscopy.
abstract: Fourier transform horizontal attenuated total reflectance (FT-HATR) was used to examine changes in the secondary structure of gluten proteins in a flour-water dough system during mixing. Midinfrared spectra of mixed dough revealed changes in four bands in the amide III region associated with secondary structure in proteins: 1317 (alpha-helix), 1285 (beta-turn), 1265 (random coil), and 1242 cm (-1) (beta-sheet). The largest band, which also showed the greatest change in second derivative band area (SDBA) during mixing, was located at 1242 cm (-1). The bands at 1317 and 1285 cm (-1) also showed an increase in SDBA over time. Conversely, the band at 1265 cm (-1) showed a corresponding decrease over time as the doughs were mixed. All bands reached an optimum corresponding to the minimum mobility of the dough as determined by the mixograph. Increases in alpha-helix, beta-turn, and beta-sheet secondary structures during mixing suggest that the dough proteins assume a more ordered conformation. These results demonstrate that it is possible, using infrared spectroscopic techniques, to relate the rheological behavior of developing dough in a mixograph directly to changes in the structure of the gluten protein system.
authors.affiliation: Grain Marketing & Production Research Center, Agricultural Research Service, U.S. Department of Agriculture, Manhattan, Kansas 66502, USA. brad.seabourn@ars.usda.gov
authors.forename: Bradford W
authors.initials: BW
authors.lastname: Seabourn
authors.forename: Okkyung K
authors.initials: OK
authors.lastname: Chung
authors.forename: Paul A
authors.initials: PA
authors.lastname: Seib
authors.forename: Paul R
authors.initials: PR
authors.lastname: Mathewson
mesh_terms: D001939:Bread / Q000032:analysis; D005433:Flour / Q000032:analysis; D005511:Food Handling; D005983:Glutens / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012212:Rheology; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D014867:Water
chemical_list: D014867:Water; D005983:Glutens