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United States Department of Agriculture

Agricultural Research Service

Title: Barley Proteins: Thermal and Rheological Properties

Authors
item Mohamed, Abdellatif
item Peterson, Steven

Submitted to: American Association of Cereal Chemists Meetings
Publication Type: Abstract Only
Publication Acceptance Date: September 14, 2005
Publication Date: September 14, 2005
Citation: Mohamed, A., Peterson, S.C. 2005. Barley proteins: thermal and rheological properties [abstract]. American Association of Cereal Chemists Meetings. Paper No. 122.

Technical Abstract: Barley protein isolate (BPI) was prepared using hexane defatted commercial barley flour. BPI was extracted in 0.05 N NaOH in a 10:1 ratio solvent:flour. The BPI was precipitated by adjusting the pH to 4.5 and freeze-dried. The thermal properties of the BPI were determined by Modulated Differential Scanning Calorimetry (MDSC). The onset temperature, peak temperature, and deltaCP were recorded for low moisture (4%) and high moisture (50%) samples. BPI exhibited a glass transition (Tg) with 140 deg C onset, 153 deg C middle, and 165 deg C end temperature with a deltaCP of 0.454. The high moisture content sample showed a Tg at 89 deg C, 91 deg C, 94 deg C and 0.067 deltaCP. Rheological properties of a 30% (w/w) suspension were determined using an ARES rheometer. To determine the linear viscoelastic range of the suspension, G prime was observed as a function of strain. The magnitude of G prime was greater than G double prime for all tested oscillatory frequencies for 0.1–100 rad/s. The strain value at which linear behavior ceased and nonlinear behavior began ranged from 3-10%.

Last Modified: 10/30/2014
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