|Seabourn, Bradford - Brad|
Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 7/25/2005
Publication Date: 9/11/2005
Citation: Xie, F., Seabourn, B.W., Chung, O.K., Seib, P.A. 2005. Study of wheat gluten secondary structure conformational changes in frozen dough using FT-HATR Mid-Infrared Spectroscopy.. Abstract No. 245 in: 2005 AACC Annual Meeting Program Book. p.146. Meeting Abstract. Interpretive Summary:
Technical Abstract: Breadmaking quality of frozen dough is usually inferior to that of freshly mixed dough. A change in gluten structure during freezing and thawing might be one of the reasons that frozen dough has a poorer end-use performance than fresh dough. We investigated changes in wheat gluten secondary structure resulting from freezing and thawing of flour-water “model” doughs optimally mixed, using six hard red winter wheat flours of varying protein content and optimum mix time. Doughs were scanned in the mid-infrared region of the electromagnetic spectrum using Fourier transform horizontal attenuated total reflectance (FT-HATR) mid-infrared spectroscopy. Frozen storage time was 0 min, 24 hr, 1 and 2 weeks, and the thawing time was 45 min for all frozen doughs. The protein secondary structures such as beta-sheet (1242 cm<sup>-1</sup), beta-turn (1285 cm<sup>-1</sup), and alpha-helix (1317 cm<sup>-1</sup) decreased, whereas random coil (1265 cm<sup>-1</sup) and alpha-helix (1336 cm<sup>-1</sup) increased, in general, with frozen storage time. The greatest changes for all of the secondary structures occurred within the first 24 hr of frozen storage. For each sample, the most significant change occurred with a decrease in beta-sheet structure. Secondary structure changes in gluten after freezing and thawing cycles were opposite from the changes in secondary structure observed during the dough-mixing and development processes. At present, we do not know if the alteration of secondary structure of gluten resulted from the process of freezing, dough relaxation during thawing or a combination of both. Secondary structural characteristics of gluten protein in frozen and thawed doughs were similar to secondary structural characteristics of an undermixed or undeveloped dough.