In this study, two in vitro digestion models were employed to compare the rate of lipolysis in soybean oil (SBO), pomegranate oil (PGO), a physical blend (PHY, 1:1 molar ratio of SBO:PGO, w/w), and their enzymatically interesterified oil (IO). In the pH-stat digestion model (emulsified oils with bile salts), PGO emulsion containing 74.7% conjugated form of linolenic acid (CLn) showed a significantly lower release rate of free fatty acid (FFA) than the other oil emulsions (p < 0.05). In FFA release rates and oil droplet sizes between PHY and IO emulsions, no significant differences were observed (p > 0.05). In a simulated model of small intestinal digestion, the lipolysis rates of SBO, PGO, PHY, and IO after digestion for 30 min in digestion fluids were 80.4%, 66.5%, 74.8%, and 77.0%, respectively. The rate of lipolysis in PGO was significantly lower than that in SBO (p < 0.05), and the lowest lipolysis rate was observed in the conjugated form of trilinolenoyl glycerol (CLn-CLn-CLn).
Keywords: conjugated linolenic acid; in vitro digestion model; lipolysis; triacylglycerol species.