Physicochemical Properties Of Dietary Fiber From Three Fruits And Vegetables And Its Effect On Lipid Metabolism In High Fat Rats

Dietary fiber is a type of carbohydrate that can not be digested and absorption by human. However, it has important biological functions, and has closely connection with human health, especially for the cardiovascular and other chronic metabolic diseases.In this study, we have taken apple dietary fiber (ADF), carrot dietary fiber (CDF), Jerusalem artichoke dietary fiber (JADF) as examples. We’ve measured microstructure and crystal structure of those three kinds of fibers as well as the conventional ingredients of dietary fiber, Meanwhile, we’ve established the dietary fat in animal models with intervention and we’ve got to know the structure of lipid metabolism.Finally, we have found the mechanism of lipid-lowering dietary fiber in the molecular level by measuring the liver, epididymal fat peroxisome proliferator-activated receptor a (PPARa) and peroxisome proliferator-activated receptor y (PPARy) of mRNA expression.The main conclusions are as follows:Firstly, microstructure of dietary fiber and its water holding capacity, and oil holding, swelling, etc. have a certain relevance. For example, the water retention and swelling for loose, small particles of dietary fiber is significantly better than larger particles of dietary fiber.The water retention, swelling in this group are both significantly higher than the ADF, CDF(P<0.05).Secondly, three kinds of dietary fibers exhibit two-phase coexistence region of crystalline and amorphous.Thirdly, ADF, CDF and JADF have the ability to delay glucose dialysis. The ability of postprandial blood glucose in JADF is better than in ADF and CDF.Fourthly, by differential scanning calorimetry (DSC), denaturation temperature, enthalpy value and the temperature difference of ADF are respectively 112.6 ℃,51.79 J/g and 82.2 ℃. Denaturation temperature, enthalpy value and the temperature difference of CDF are respectively 113.8 ℃,46.99 J/g and 96.4 ℃. Denaturation temperature, enthalpy value and the temperature difference of JADF are respectively 117.7 ℃,66.41 J/g and 70.8 ℃. The ability of thermal stability in those three kinds of dietary fiber:JADF> ADF> CDF.Fifthly, after the autopsy in rats, we found that liver basal diet group presented deep red and normal size, high-fat diet group liver presented white color, showing characteristics of fatty liver.Sixthly, dietary fiber can improve the urine of rats metabolism and the ADF group is better than CDF group but less than JADF group.Seventhly, TC, TG, AI, LDL-C increased by high-fat diet can be significantly decreased byall three kinds of dietary fiber. The ability in JADF is more significant (P<0.05)and can inhibit the HDL-C levels, and effectively improve liver fat status, reducing the fat of the degeneration of the liver cells.Eighthly, by scanning electron microscopy method, the rats in each group abdominal aorta wall ultrastructure observation of three dietary fiber on atherosclerosis have played an inhibitory effect in terms of:Jerusalem artichoke dietary fiber> Apple dietary fiber> carrot dietary fiber.Ninthly, comparing to the basal diet rat group, PPAR a, PPAR y mRNA expression levels of liver and epididymal fat increased in other groups. Dietary fiber intake effectively provents PPAR y pathway from being hurted, which plays a role in the protection of liver function and promotes catabolism of fat. Adding dietary fiber in diet can effectively increase PPAR a, PPAR y mRNA expression levels of liver and epididymal fat in rats is highest in JADF, while the CDF group is the weakest.