In Vitro Assessment of the Bioaccessibility of Tocopherol and Fatty Acids from Sunflower Seed Oil Bodies
2009
White, Daniel A. | Fisk, Ian D. | Makkhun, Sakunkhun | Gray, David A.
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 acids from oil bodies (0.6 and 8.4%, respectively) was significantly lower than that from the Tween 20 stabilized emulsion (35 and 52%, respectively) and the whey protein isolate stabilized emulsion (17 and 33%, respectively). These in vitro results suggest that oil bodies could provide a natural emulsion in food that is digested at a relatively slow rate, the physiological consequence of which may be increased satiety.
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