Study On The Physicochemical Properties And Applications Of Microcapsulated Lutein Prepared By Different Methods

Lutein is one type of carotenoid, which is widely spread in nature, holding strong antioxidation ability. Lutein is known as its powerful coloration ability, meanwhile Lutein posseses many other significant physiological functions such as preventiving macular caused by age, and reducing the risk of cancer, cardiovascular disease and oculopathy. However, its application in food industry is limited by the instability towards oxygen, light and temperature due to the eight-conjugated-double-bonds structure. On the other hand, the poor solubility is another obstacle for its application. In this paper, we studied the preparation of Lutein microcapsules prepared by spray-drying method, complex coacervation method and nanocapsule methods, respectively. We also studied the physicochemical properties and stability of the three kinds of microcapsules. The purpose of the work is to give some guides about the application in pratice for various microcapsule methods.Firstly, the technique of spray-drying method was studied. The condition of preparing the microcapsule was as follows: the wall material was consisted of maltodextrin and gum arabic, and the ratio between them was 1:1; the solid content concentration was 20%; the ratio of core to wall-material was 1:6. The microcapsules were prepared under the techiniques parameter that the emulsion was homogened at 40 MPa for two times and the temperature for inlet and outlet wind being 180℃and 80℃,respectively. The satisfied morphology was obtained with the yield of 71.76% , encapsulation efficiency of 83.61% and the loading capacity of 10.89%.Then we optimized the techniques parameters of complex coacervation method. The optimum condition was as follows: the ratio of gelatin and gum arabic as the wall material was 1:1 and the concentration of them was 1%; the ratio of core and wall-material was 1:2; the microcapsules were formed under the pH 4.0 at the temperature 40℃, stirring at the speed of 400 r/min; TG which amount about 0.25 g / g gelatin was added for crossing-linking for 5 h. The microcapsules were obtained with the yield of 85.24%, encapsulation efficiency of 92.77% and the loading capacity of 35.10%.Next the nanocapsules were carried out. The final optimized parameters were as follows: the chitosan/Tpp mass ratio was 3:1, the concentration of chitosan was 0.075%, the ratio of chitosan/Lutein was 1:1, the ratio of oil/emulsification of HLB 12.5 was 3:2, pH 4.5. The obtained Lutein-loaded chitosan particles were spherical in shape with an average diameter of 121.8 nm and PDI 0.255 as observed by TEM. Encapsulation efficiency of Lutein in the nano-microcapsules was 81.50%.Finally, the stability of three microcapsulations in solid and liquid systems was evaluated. In the solid system, we assessed the retention for three types of microcapsulations at the temperature 150℃, while in the liquid system we assessed the release stability between complex coacervation microcapsules and nanocapsules. The results showed the technology of microencapsulation played an important role in improving the stability of Lutein. Furthermore, the spray-drying microcapsules were only suit for the solid system, and the complex coacervation microcapsules had a good preformance in stability against heating and heavy moisture. The nanocapsule was a method for microcapsulations prepared in low temperature, especially it could provide great protection to the core in the liquid system.