Effect Of Twin-screw Extrusion On ?-glucan In Whole Oats And Gluten Of Wheat Flour

Twin-screw extrusion was an important processing technology in the food industry. As the raising awareness of health diet, oat, which was rich in dietary fiber, minerals, high quality protein and other nutrients,was paid attention. While, Improving the oat processing quality and nutritional characteristics were becoming a hot spot in the food industry. In addition, Based on celiac patients healthy diet needs, Reducing the gluten content in wheat flour was an important direction of food allergy scientific questions.There had four aspects in this thesis, including analysis of physical and chemical properties of Baiyan 2 oats twin-screw extrudate, effect of twin-screw extrusion on beta-glucan content of Baiyan 2 oats, the influence of adding wheat flour on oat squeeze out the effect of physical properties and effect of double screw extrusion on wheat gluten. The main research methods, results and conclusions were as follows:(1)Physical and chemical properties of Baiyan 2 oats twin-screw extrudate were investigated. It was shown that, while the extrusion conditions were set at 22% feed moisture content, 160? temperature, and 294 rpm screw speed with a fixed feed rate of 31.2 rpm, the expansion ratio of oats extrudate was 1.16. Maillard reaction was occurred during extrusion, resulting in changes of colors and amino acid content. L*, a*, and ?E decreased, while, b* increased. Total amino acid content decreased by 5.44%. Compared to original material, oats extrudate had a rough surface. Water absorption index increased by 378.4%, water solubility index decreased by 1.08%, soluble beta-glucan content increased by 62.2%, apparent viscosity of extract by in vitro digestion increased, and both polymerization and depolymerization reaction occurred during extrusion. Twin-screw extrusion processing was proved that could improve the sensory and nutritional properties, the processing characteristics and cholesterol-lowering functional propertiesof Bai Yan 2 oat products.(2)Through the sigle factor experment, the effect of extrusion parameters, which included the feed moisture, extrusion temperature, feed speed and screw speed, on soluble beta-glucan cotent of Baiyan 2 oats were explored. The parameters of the process of extrusion of oat beta-glucan were as follows: feed moisture 22%, extrusion temperature 140?, feed speed 25.2 rpm, screw speed 49 rpm. Under these conditions, the content of soluble beta-glucan up to 40.5mg/g.(3) Effect of twin-screw extrusion on beta-glucan content of Baiyan 2 oats was studied. The results found that with wheat flour increasing, the expansion of extrudates were improved gradually. When the proportion of wheat belowed 30%, WSI of extrudates of increased, WAI of extrudates has significantly increased when proportion of wheat flour surpassed 70%. Extrudates' color changed(a* decreased after a incresing, b* increased, L* decreased), the largest color difference came form the extrudate, in which proportion of wheat flour was 70%. With the increase of wheat flour content, extrusion material structure gradually decline, extrudates' apparent became more smooth and better integrity, total beta glucan content gradually decreased, soluble beta glucan content gradually decreased. When the proportion of wheat flour blowed 50%, with the increase of adding amount of wheat flour, material physical extract viscosity decreased gradually after digestion. When the proportion of wheat flour surpassed 50%, instead. After digestion, the ratio of low molecular weight(Mw < 103) component decreased in extrudates physical extract. the ratio of the molecular weight(103 < Mw < 105) component increased except extrudates in which proportion of wheat flour was 50% and 70%. When the ratio of wheat flour surpassed 50%, high molecular weight(Mw > 105) component incresed significantly. Poor and hard performace of oats extrusion product was solved effectively.(4)Whole wheat flour was extruded. Through the sigle factor experment, the effect of extrusion parameters, which included the feed moisture, extrusion temperature, screw speed and feed speed, on gluten content of supernatant of wheat flour extrudates after digestion were explored. The parameters of the process of extrusion of gluten flour were as follows: feed moisture 18%, extrusion temperature 170?, feed speed 30 rpm, screw speed 210 rpm. Under these conditions, the content of gluten was the lowest, which was 4456 ppm. While, It was proved that reducing gluten content of wheat to below 20 ppm using twin-screw extrusion was infeasible.