Sonication, wheat proteins

High-performance liquid chromatography (HPLC) was first applied to cereal proteins by Bietz (1986). Size-exclusion HPLC (SE-HPLC) has been used to quantify cereal proteins it separates proteins according to molecular size. Wheat proteins have been the most studied of the cereals. The preferred solvent has been dilute sodium dodecyl sulfate (SDS)/buffer. A wheat flour suspension (-1.0 mg/mL) is sonicated under conditions (time, intensity) that solubilize almost all, if not all, of the protein without altering quantitation of the main protein classes (see discussion in Chapter 9). 

The use of symmetrical flow FFF hyphenated with RI and MALLS detectors to assess the size and shape of sequentially dilute HAc extracted monomeric rich and sonicated HAc extracted polymeric rich wheat proteins was reported by Stevenson et al. - values at peak for the monomeric extract varied from 31,000 to 33,000 and increased to approximately 110,0(X) at later elution times. Results for all five varieties of wheat included in this study were similar for the monomeric wheat protein extracts. The profiles of polymeric extracts for the five wheat samples ranged from 225,000 to 300,000 at peak and increased to approximately 7x10 after 60 min of elution as shown in Fig. 2. values for the polymeric protein fraction showed relatively small changes with increasing elution time (M ), suggesting that the larger polymeric proteins tend toward a more compact structure than the lower polymeric proteins. 

NK Singh, GR Donovan, IL Batey, F MacRitchie. Use of sonication and size-exclusion high-performance liquid chromatography in the study of wheat flour proteins. 1. Dissolution of total proteins in the abscence of reducing agents. Cereal Chem 67 150-161, 1990. 

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