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Contribution of Hydrophobic Soluble Gluten Proteins, Fractionated by Hydrophobic Interaction Chromatography in Highly Acetylated Agarose, to Dough Rheological Properties

¹Graduate student, Centro de Investigacion en Alimentacion y Desarrollo. Hermosillo, Sonora, Mexico. E-mail: pitorres@guayacan.uson.mx ²Corresponding author. Professor, Centro de Investigacion en Alimentacion y Desarrollo. Carretera a la Victoria Km 0.6. Apdo. Postal 1735 C.P. 83000. E-mail: lvazquez@cascabel.ciad.mx Phone: (62) 800058. ³Researcher, Universidad de Sonora. Hermosillo, Sonora, Mexico.

Hydrophobic interaction chromatography with highly acetylated agarose in 1-mL columns was used to fractionate gliadins and acid-soluble glutenins. Proteins were eluted in two fractions, the first with acetate buffer (pH 3.6) containing 35% propanol, and the second with Tris buffer in 8M urea. The proportion of eluted protein in the second fraction was called the surface hydrophobicity index. The study included 20 wheat samples of different baking qualities. Multiple regression analysis using the general linear model combined with the stepwise technique was used to relate the surface hydrophobicity index of soluble gluten proteins to specific dough rheological characteristics. Surface hydrophobicity index of gliadins and acetic acid soluble glutenins explained part of the variability of swelling index, extensibility, and work of deformation (dough strength) measured with the alveograph, and part of the farinograph water absorption variability, but showed no relationship to dough mixing characteristics. Hydrophobic soluble gluten proteins fractionated by hydrophobic interaction chromatography (HIC) explained a part of the variability of dough rheological properties.