In Vitro Assessment of the Bioaccessibility of Tocopherol and Fatty Acids from Sunflower Seed Oil Bodies

The in vitro digestibility (proteolytic and lipolytic) and bioaccessibility of nutritionally important compounds (α-tocopherol and fatty acids) have been studied for natural sunflower (Helianthus annuus) oil body suspensions in comparison to artificial emulsions emulsified with polyoxyethylene-20-sorbitan-monolaurate (Tween 20) or whey protein isolate. Proteolytic digestion of emulsions with pepsin (pH 2) promoted significant increases in mean particle size of the whey protein isolate stabilized emulsion (1.8−2.9 μm) and oil bodies (2.3−22.5 μm) but not the Tween 20 stabilized emulsions. SDS-PAGE of proteolytic digestion products suggested degradation of the stabilizing oleosin protein (ca. 18−21 kDa) in oil bodies. The rate of oil body hydrolysis with lipase was significantly slower than the lipase-catalyzed hydrolysis of the artificial emulsions and exhibited a prolonged lag phase. Results from simulated human digestion in vitro suggested that the mean bioaccessibility of α-tocopherol and total fatty ac...