Enhancement of physical stability and bioaccessibility of tangeretin by soy protein isolate addition

Abstract Soy protein isolate (SPI) was selected to fabricate supersaturated self-emulsifying nanoemulsions, aiming to enhance physical stability and bioaccessibility of hydrophobic tangeretin. Dissolution studies demonstrated that tangeretin had the highest solubility in Tween 80, followed by oil phase solutions, and polymer solutions. Supersaturated tangeretin in oil phases easily formed crystals. That metastable zone was found to vary with its initial concentrations. After encapsulation by nanoemulsions, the addition of glycerol compressed the retention amount of tangeretin from 76% to 53%, but benefited the transparency. Whereas, the combination of glycerol and SPI could not only maintain high-loading tangeretin (>85%), but also provide high transparency for nanoemulsions. When tangeretin concentration was 4.83 mM, combination of 50% glycerol and 1% SPI could maintain around 88% tangeretin in the nanoemulsion within one month. Its bioaccessibility of different systems were at 60–65%. These findings can provide useful information for protein to be a potential precipitation inhibitor.