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In this paper, main studies were as follows: (1) Three kinds of dietary fibers, including insoluble dietary fibre(IDF), soluble dietary fiber(SDF) and the mixed dietary fiber with 1:3 of the ratio of SDF to IDF, were prepared from maize bran by different methods such as acid - base technology, acid system and extrusion method; their properties were also determined and compared. (2) The model of TFA resulted in hyperlipidemia mice was established. (3) The effects of three dietary fibers on blood-fat and inhibiting ability of hyperlipoidemia rats were studied.(1) Studies on preparation and properties of three dietary fiber samplesTechnological Process for preparation of IDF from maize bran by acid - base technology was as following: maize bran→dry→crushing and sift through 100μm→alkaline leaching(the ratio of wheat bran to water 1:9, concentration 0.5mol/L, temperature 100℃)→filter→washing to neutral→acid hydrolysis(pH 1.5-2.0)→solid-liquid eparation→washing to neutral→grinding→product. purity of IDF was up to 96.78%. Technological Process for preparation of SDF from maize bran by acid system was as follows: maize bran→dry→crushing and sift through 100μm→constant temperature bath (the ratio of wheat bran to water 1:10, pH5, temperature 80℃and action time 70min)→centrifugal (3000r/min, 20 min)→supernatant→vacuum concentration→alcohol-precipitation (the ratio of supernatant to alcohol 1:4 )→standing (2h)→drying filter cake→grinding→product. purity of SDF was up to97.03 %. Technological Process for mixed dietary fiber from maize bran by extrusion method was as following: maize bran→dry→crushing and sift through 100μm→extrusion (12% of material moisture content, 80℃of temperature, 100 r/min of screw speed, three sections of screw length)→crushing→mixed dietary fiber.SDF content was 14.74 %, IDF content was 38.51 %, the ratio of SDF to IDF was 1:3.08.Water holding capacity, oil absorption capacity, swelling capacity, nitrite adsorption capacity, cholesterol absorption capacity, viscosity , Scavenging ability of three dietary fiber samples were studied. The results showed that water holding capacity, swelling capacity and oil absorption capacity of the mixed dietary fiber was best, increased 2.82%, 9.34 % and 23.86 % than that of SDF, as well as 19.99 %, 17.58 % and 11.99 % than that of IDF; Nitrite absorption capacity was stronger in the acidic conditions(pH2, simulated stomach acidic conditions)than in the neutral conditions(pH7, simulated intestinal environment), furthermore on both conditions, the sequence of nitrite adsorption capacity was IDF> mixed dietary fiber >SDF; cholesterol absorption capacity was stronger in pH7 than in pH2, and cholesterol absorption capacity of mixed dietary fiber was best, adsorptions of cholesterol of IDF, SDF, SDF:IDF(1:3) was 4.98 mg/g, 7.33 mg/g, 7.62 mg/g, respectively; sample viscosity increased gradually with the concentration increasing. On the same concentration, SDF viscosity was highest, mixed dietary fiber took second place, and IDF least; Three dietary fibers all have strong scavenging ability, the sequence of scavenging ability was mixed dietary fiber >SDF> IDF.(2)establishment model of TFA resulted in hyperlipidemia miceThe mice were fed with ATM(tans-fatty acid and lard) for 4 weeks, at TFA contents of 5 % and 11 % , its total cholestero was up to 5.27 mmol/L, it suggested that modeling was success . The mice were fed with STM(tans-fatty acid and seed fat)for 4 weeks, at TFA contents of5 % and 11 % , its total cholestero was up to 5.27 mmol/L ,it suggested that modeling was success. (3) The effects of three dietary fibers on blood lipid and antioxid action of experimental hyperlipidemia mice caused by trans-fatty acidThe ATM(5 %, 11 %TFA) and STM(9 %, 13 %TFA) resulted in hyperlipidemia mice, which were administrated orally with maize bran dietary fiber of low dose group (2.5g/kg.bw), moderate dosage group (5g/kg.bw) and high dose group (10g/kg.bw). The rusults showed that in the condition of STM(9 %, 13 % TFA) modeling, the moderate dosage group of IDF could obviosly decrease TC, TG, LDL-C, but enhance HDL-C. On the condition of ATM(5 %, 11 % TFA) modeling, high dose group of IDF could obviosly decrease TC, TG, LDL-C, but enhance HDL-C. It suggested that the influence of ATM on Blood lipid was greater than STM .On the condition of STM(9 %, 13 % TFA) modeling and ATM(5 %, 11 % TFA) modeling, high dose group of IDF could obviosly decrease MDA, NO, enhance TAOC, SOD significantly. In the condition of STM(9 %, 13 % TFA) modeling and ATM(5 %, 11 % TFA) modeling, high dose group of SDF could obviosly decrease TC, TG, LDL-C, MDA, NO, enhance HDL-C, TAOC, SOD significantly.In the condition of STM(9 %, 13 % TFA) modeling, low dose group of SDF:IDF(1:3) could obviosly decrease TC, TG, LDL-C, enhance HDL-C significantly. In the condition of ATM(5 %, 11 % TFA) modeling, high dose group of SDF:IDF(1:3) could obviosly decrease TC, TG, LDL-C, enhance HDL-C significantly. In the condition of STM(9 %, 13 % TFA) modeling and ATM(5 %, 11 % TFA) modeling, the moderate dosage group of SDF:IDF(1:3) could obviosly decrease MDA, NO enhance TAOC, SOD significantly.On the condition of ATM(5 %, 11 % TFA)modeling, the effects of SDF:IDF(1:3) and SDF on reducing blood lipid and anti-oxidation capacity had little difference,both were better than IDF. In the condition of STM(9 %, 13 % TFA) modeling. The influence of SDF:IDF(1:3) on reducing blood lipid was greatest,SDF took second place, IDF least. The influence of SDF:IDF(1:3) and SDF on anti-oxidation capacity had little difference, both were better than IDF.
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