Sunflower seed protein: defatting, structural characterization and property analysis.

The preparation method and protein purity are crucial factors influencing the use of sunflower seed proteins in the food industry. In this study, sunflower seed press cake was defatted using subcritical butane, isopropyl alcohol and n-hexane, producing meal protein, protein concentrate, and protein isolate. A systematic analysis of the structural and functional properties of these proteins revealed that the subcritical butane and isopropyl alcohol extracted protein yield and color, protein structure was relatively loose, denaturation temperature was higher, the prepared sunflower seed protein solubility and other functional properties were better than traditional hexane extraction. Additionally, the protein isolate demonstrated superior solubility (46.38-52.34 %), emulsification stability (31.76-41.97 %), and oil holding capacity. The protein concentrate exhibited significant advantages in gel properties and water holding capacity. These findings supported the development of green, efficient, and sustainable methods for the optimal utilization of sunflower seed proteins at different purity levels.