| Using soybean protein isolate, maltodextrin and arabia gum as wall materials, walnut oil microcapsules was separately prepared by spray drying and vacuum freeze-drying. The walnut oil microcapsules was accelerately oxidized at 62 ℃ for 14 d. The peroxide value, anisidine value and total oxidation value were determined. The simulated intestinal juice and gastric juice were prepared, and the release rates of oil and free fatty acid of walnut oil microcapsules in vitro were determined. Kunming mice aged 6-8 weeks were selected and randomly divided into eight groups after adaptive feeding: blank control group, high-fat model group, walnut oil microcapsules and walnut oil low, medium and high-dose groups. They were administrated continuously for four weeks. Their body weight, liver index, blood index and liver cell index were measured, and the damages of liver and fat cells were observed by staining. The results showed that the encapsulation rate of the walnut oil microcapsuls prepared by spray drying was 8191%, the moisture content was 2.40%, the fluidity was high and the solubility was good. Through 62 ℃ accelerated oxidation test for 14 d, microencapsulation could effectively alleviate the oxidative deterioration of walnut oil, and the oxidation degree of walnut oil microcapsule prepared by spray drying was lower than that by freeze-drying, and the peroxide value, anisamine value and total oxidation value were lower. The walnut oil microcapsules prepared by spray drying were digested by simulated gastric juice and intestinal juice, and the release rate of oil was up to 91.13%, higher than that by freeze-drying, and the releasing of free fatty acids was also higher. Walnut oil microcapsule prepared by spray drying could effectively alleviate the increase of body weight and liver index, decrease the contents of serum total cholesterol (TC) and triglyceride (TG), reduce the levels of low density lipoprotein cholesterol (LDL-C), increase the level of high-density lipoprotein cholesterol (HDL-C), increase the level of glutathione peroxidase (GSH-PX) and superoxide dismutase (T-SOD) in liver of mice, and reduce the level of malondialdehyde (MDA) in liver, which could effectively inhibit fatty degeneration and oxidative damage of liver in high-fat mice. |
