Influence of triacylglycerol on the physical stability and digestion fate of triacylglycerol–bergamot mixed-oil emulsions with nobiletin

Abstract Nobiletin is a citrus flavonoid with poor water solubility, which limits its application. To investigate the effects of emulsions on the bioavailability of nobiletin, long-chain triglycerides (LCT, i.e., corn oil) and medium-chain triglycerides (MCT) were used in combination with bergamot oil at different mixing ratios (i.e., 1: 0, 3: 1, 1: 1, 1: 3, and 0: 1) as the oil phase to produce nobiletin–encapsulating emulsions by high-pressure homogenization. The emulsion stability, digestion fate, and bioavailability of nobiletin were systematically investigated. The results showed that triacylglycerol–bergamot oil at the ratio of 1: 3 was the most stable. The hydrolysis rate of triacylglycerol–bergamot oil emulsions increased with increasing triacylglycerol: bergamot oil ratio. The total bioavailability of nobiletin in corn oil–bergamot oil emulsions was higher than that of pure bergamot oil and MCT–bergamot oil emulsions during in vitro digestion, due to the higher hydrolysis rate of corn oil–bergamot oil and greater solubilization capacity of micelles formed by bile salts and long-chain fatty acids (LCFAs) from corn oil. Nobiletin bioavailability was highest in the 3: 1 corn oil: bergamot oil emulsion. This simulated digestion study may be useful for designing emulsion-based delivery systems to control the bioavailability of hydrophobic nutrients.