Physicochemical Properties of 2S Albumins and the Corresponding Protein Isolate from Sunflower ( Helianthus annuus )

Sunflower albumins (SFAs) are a diverse group of proteins present in sunflower isolates, with a sedimentation coefficient of approximately 2S. This research presents a detailed study of the influence of pH on the structure and solubility of SFAs. The effect of temperature on the structure of SFAs was also studied. Furthermore, the solubility of a sunflower isolate (SI) was studied and discussed in terms of its main protein components (SFAs and helianthinin). The native structure of SFAs revealed to be very stable against pH changes (pH 3.0 to 9.0) and heat treatment (>100 °C), and their solubility was only marginally affected by pH and ionic strength. The solubility of the sunflower isolate as a function of pH seems to be dominated by that of helianthinin: SI ( I = 30 m M ) showed a U‐shaped solubility curve with a minimum between pH 4.0 and pH 6.0.