Enhancement of the physicochemical and in vitro release properties of lutein by gelatin/octenyl succinic anhydride (OSA)-modified starch composite as vehicles

In this study, the lutein was microencapsulated by complex coacervation with gelatin and OSA starch as vehicles, and the physicochemical and in vitro release properties of the microcapsules were evaluated followed by the spray drying or freeze-drying method. Preliminary assays of coacervation indicated that a higher encapsulation efficiency was obtained at the gelatin/OSA starch volume ratio of 5:4 and the core/wall material volume ratio of 1:8 (v/v) followed by the spray-drying method. The lutein-gelatin-OSA microcapsules had a higher solubility, antioxidant activity, thermostability, relative humidity stability and sustained in vitro release compared to the free lutein. Fourier transform infrared data indicated that the encapsulated lutein interacted with gelatin and OSA starch was mainly through hydrogen bonding, hydrophobic and electrostatic interactions. The freeze-dried microcapsule was observed with a more regular shape, smaller particle size in morphology and confirmed with better thermal stability from the differential scanning calorimetry results while the spray-dried microcapsules obtained a higher cumulative release rate of lutein and higher antioxidant activity. The results of this study are expected to contribute to the design and commercial application of gelatin-OSA starch complex-based delivery systems for hydrophobic nutraceuticals with desired physicochemical properties and digestive performance.