The surface compositions and structure of oil bodies (OBs) are dependent on the oil crop, and these factors affect in vitro gastrointestinal digestion behaviors. Herein, a comparative study was conducted to examine the in vitro gastrointestinal digestion characteristics of two natural emulsions prepared with soybean seeds and rapeseed OBs during gastrointestinal digestion process. The average particle size of soybean OBs and rapeseed OBs emulsions was 0.46 and 5.02 µm, respectively. The droplet size of soybean seed and rapeseed OBs emulsions was large with relatively low zeta-potentials at 30 min digestion time in simulated gastric fluid condition. The droplet size of two natural OBs emulsions decreased with increasing digestion time in simulated gastric fluid condition. The average droplet size of both emulsions gradually decreased with increasing digestion time in simulated intestinal fluid conditions. The zeta-potential of the two emulsions increased with increasing digestion time in simulated intestinal fluid conditions. The extent of free fatty acids of soybean OBs emulsions was significantly higher than rapeseed after 20 min digestion time in simulated intestinal fluid conditions. The obtained results suggested that plant OBs could be useful as natural emulsifiers in the development of functional food and achieve controlled release of bioactive compounds from emulsions during gastrointestinal digestion.
Keywords: emulsion; gastrointestinal digestion; oil bodies.