Effects of Temperature, Sonication Time, and Power Settings on Size Distribution and Extractability of Total Wheat Flour Proteins as Determined by Size‐Exclusion High‐Performance Liquid Chromatography

Abstract

Cereal Chem. 77(5):685-691The size-exclusion (SE) HPLC profile of total protein extract obtained by sonication of flour samples at ambient temperature showed marked instability on reinjection. Instability was related to the presence of flour proteases that were inactivated by thermal treatment of flour samples at 60°C. Extraction of flour protein by sonication was a function of ultrasonic energy (sonication time × power product) delivered to flour sample. As protein solubility increased, the proportions of the earliest eluted SE-HPLC fractions (F1 and F2) increased. Oversonication of proteins evidenced by a decrease in F1 amount at the benefit of F2 occurred below the sonication energy level needed for total protein extraction. Ultrasonic energy level was adjusted to allow total protein extraction while limiting oversonication. The sonication procedure was applied on 27 flour samples of contrasting dough strength to extract total proteins. Absolute amount of protein extractable by sonication, determined from SE-HPLC area, was strongly correlated with flour protein content. Very significant and equivalent relationships were found between alveographic W index and absolute amount of either unextractable protein extract or F1 of SE-HPLC profile from total protein extract.

“Productivity, quality and sustainability of winter wheat under long-term conventional and organic management in Switzerland”

“…Protein fractions were determined by size exclusion (SE) HPLC. For this purpose, the method of Morel et al (2000) was slightly modified and a phosphate buffer was used to extract SDS-soluble proteins. Five fractions of SDS-soluble proteins (F1-F5) were separated (Dachkevitch and Autran 1989).…”

Impact of Legume Flour Addition on Pasta Structure: Consequences on Its In Vitro Starch Digestibility

“…The SE-HPLC apparatus (Waters model LC Module1 plus) was equipped with an analytical column TSK G4000-SW (Merck, France; 7.5×300 mm) and a guard column TSK G3000-SW (Merck, France) (7.5× 75 mm), as previously described. 18 Once corrected for their different solid-to-solvent ratios during extractions, areas (in arbitrary units) of SDS-soluble and DTE-soluble proteins were added, and the sum (i.e. total extractable proteins) was expressed as percents of the corresponding total area calculated for semolina (for durum wheat pasta) or a blend of 65% semolina and 35% legume flour (for legume pasta; on equivalent dry protein basis).…”

“…In durum wheat semolina, fractions S1 (6%) and S2 (19%) could be assimilated to polymeric glutenin proteins, fractions S3 (7%) and S4 (34%) could be assimilated to gliadins and fraction S5 (14%) corresponded to watersoluble proteins (albumins and globulins) 18 (Figure 8b). Split pea and faba bean proteins were mainly composed of proteins with a molecular weight inferior to 100 kDa.…”

Inactivation kinetics of pectin methylesterase and cloud retention in sonicated orange juice

“…Cloud retention after sonication may be attributed to dispersion stability of macromolecules due to the promotion of certain chemical reactions during sonication (Floros & Liang, 1994;Mason, 1998;McClements, 1995). High-intensity ultrasound enhances protein solubility (Krešić, Lelas, Jambrak, Herceg, & Brnčić, 2008) by changing protein conformation and structure in such a way that hydrophilic parts of amino acids from inside are opened toward water (Morel, Dehlon, Autran, Leygue, & Bar-L'Helgouac'h, 2000;Moulton & Wang, 1982). Lacroix, Fliss, and Makhlouf (2005) reported that electrostatic interactions between PME and its substrate pectin have a major impact on orange juice cloud stability.…”