Effects of Wall Materials on the Structure and Antioxidant Activities of the Bamboo Leaves Flavonoids Microcapsules

Abstract

In this experiment, the bamboo leaves flavonoids microcapsules were prepared by spray-drying using maltodextrin, arabic gum, gelatin, soy protein isolate and monosaccharide laurate as wall materials. The properties and encapsulation effect of microcapsules prepared by five wall materials were investigated by scanning electron microscope (SEM), laser particle size distribution, physicochemical properties and antioxidant activity. The results showed that microcapsules prepared with arabic gum had the highest encapsulation rate (91.23%±1.00%), the highest stacking density (0.53±0.01 g·cm-3), the lowest resting angle (33.27°±1.20°), and the lowest moisture content (5.55%±0.39%). These microcapsules had good fluidity and storage performance. The particle size distribution resulted in descending order as the following monosaccharide laurate (22.87 μm), soybean protein isolate (15.65 μm), maltodextrin (14.26 μm), gelatin (8.95 μm), and arabic gum (6.96 μm). The results of SEM showed that the microcapsule prepared by arabic gum was spherical and the surface was relatively smooth. The microcapsules prepared by arabic gum had higher antioxidant activity and reducibility in vitro antioxidant activity and reducibility experiments, and its IC50 of DPPH radical scavenging was 364.3 μg/mL. In conclusion, the properties of bamboo leaves flavonoids microcapsules prepared with arabic gum were obviously better than those of other four wall materials microcapsules. The results could provide technical support for the development of more stable functions of the flavonoids of fang bamboo leaves.