147 Relationship of surface hydrophobicity of gluten proteins measured by HIC using highly acetylated agarose to dough functional properties.

L. Vazquez-Moreno (1), A. I. Ledesma (2), C. Medina (2), and P. I. TORRES (1,2). (1) Centro de Investigación en Alimentación y Desarrollo; (2) Universidad de Sonora, México.

Hydrophobic interaction chromatography (HIC) with highly acetylated agarose was used to estimate gliadin and glutenin surface hydrophobicity. Protein was eluted in two fractions, the first one in pH 3.6 sodium acetate buffer containing 35% n-propanol and the second one in 8M urea. The proportion of protein eluted in 8M urea was used as a hydrophobicity index of these proteins. Wheat cultivars of diverse quality were used. Wheat was milled in an experimental Bravender Senior mill. Rheological dough properties were measured with the alveograph and the farinograph. Flour protein content was measured with the Kjedahl method while soluble proteins from extracts and elutions by the dye binding Bradford assay. Multiple regression analysis using the general lineal model with the variable selection techniques was used to obtain a model that explains the effect of surface hydrophobicity on wheat quality specific parameters. Surface hydrophobicity of gliadinas relates significantly to farinographic water absorption, whereas surface hydrophobicity of glutenins to dough strength, this measured as alveographic dough deformation energy (W). Hydrophobicity index of gliadins and glutenins measured by HIC with highly acetylated agarose showed to be a valuable wheat quality predictor.