Sunflower seed protein isolate and a process for producing the same

A process for preparing a sunflower protein isolate, said process comprising the following steps:

• (a) providing an at least partially defatted seed meal, said seed meal being a sunflower seed meal and having a proportion of dry matter ranging from 80 wt % to 98 wt %;
• (b) mixing said at least partially defatted seed meal with an aqueous NaCl solution at a pH of about 6 to 8, in order to solubilize proteins present in said at least partially defatted seed meal and to thus obtain a solubilized protein solution, wherein said aqueous NaCl solution has a NaCl concentration ranging from 0 to 1.2 mol·L−1;
• (c) separating said solubilized protein solution from solids therein;
• (d) diafiltering said solubilized protein solution through an ultrafiltration membrane system having a molecular weight cutoff of 1 to 100 kDa, said diafiltering step being effected using:
• an aqueous NaCl diafiltration solution having a NaCl concentration ranging from 0.1 to 0.6 mol·L−1;
• and
• at least 2 diavolumes of said aqueous NaCl diafiltration solution, to obtain a NaCl-diafiltered protein solution;
• (e) subsequently to step (d), diafiltering said NaCl-diafiltered protein solution through an ultrafiltration membrane system with a molecular weight cutoff of 1 to 100 kDa, using water, to obtain a purified protein solution;
• (f) concentrating said purified protein solution to obtain a purified protein concentrate;
• and
• (g) drying said purified protein concentrate to obtain said protein isolate;
• wherein said process does not contain a step of precipitation of said protein prior to the step (d).