| Résumé | The salt-extractable proteins in sunflower flour were characterized by gel chromatography, disk electrophoresis, and amino acid composition. The proteins from Commander, Majak, and Valley sunflower and a soybean control were 69-70% dispersible in 2.5% neutral salt solution. These proteins were seperated into five fractions by gel chromatography on a standardized Sephadex G-200 column. The fracctions I-V contained about 5, 49, 9, 24, and 12% of the extracted meal proteins, respectively, in the three sunflower varieties. After dialysis, fraction I contained a large proportion of nucleic acids, while chlorogenic acid appeared to be bound to only fraction V proteins. Molecular weight estimations indicated that, on the average, the five sunflower protein fractions were similar in molecular weight to the five soybean protein fractions. Sedimentation analyses of Valley fraction II showed that the major protein component in this fraction had a sedimentation coefficient of 12.1 S. The Valley proteins demonstrated fewer bands on disk electrophoresis at pH 8.9 than the soybean proteins. Amino accid analysis indicated that soybean was higher in lysine but lower methionine than sunflower. Majak proteins were higher in lysine and methionine than Commander and Valley proteins. The major protein fraction II contained high proportions of isoleucine, phenylalanine, theronine, and nonessential amino acids. The fraction IV proteins were very rich in lysine and methionine, while the fraction V in each sunflower variety was very deficient in these essential amino acids |
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