Henan University of Technology

About: Henan University of Technology is a education organization based out in Zhengzhou, China. It is known for research contribution in the topics: Catalysis & Chemistry. The organization has 7648 authors who have published 6503 publications receiving 73067 citations. The organization is also known as: Hénán Gōngyè Dàxué.

Optimization of ultrasonic extraction of polysaccharides from Ziziphus jujuba Mill. by response surface methodology.

Abstract: Ziziphus jujuba Mill. is nutritious and used as food and medicine for more than two thousand years. It has many pharmacological effects, such as elimination of fatigue, dilation of blood vessels, etc. The polysaccharide in it is one of the bioactive substances. In this paper, the ultrasonic extraction effects on the yield and activity of polysaccharide were studied. The optimum ultrasonic extraction conditions were investigated based on a Box-Behnken statistical experimental design. Response surface methodology (RSM) of three factors (ultrasonic power, extraction time and extraction temperature) and three levels was employed to optimize the yield and the antioxidant activity of the polysaccharides. The experimental data were fitted to quadratic response surface models using multiple regression analysis. The best extraction conditions were 120 W, 15 min. and 55°C for highest yield, and 80 W, 15 min. and 40°C for highest hydroxyl radical scavenging activity. The study showed that high ultrasonic power was good for obtaining high yield but bad for keeping the antioxidant activity of the polysaccharides.

Phospholipid composition and emulsifying properties of rice bran lecithin from enzymatic degumming

Abstract: The phospholipid composition and emulsifying properties of rice bran lecithin recovered from enzymatic degumming catalyzed by phospholipase A1 (PLA1) were investigated and comparing to those from citric acid and water degumming. Rice bran lecithin from enzymatic degumming (RLED) had a different phospholipid composition compared with that from water and citric acid degumming, with a particularly high lysophospholipid concentration. Meanwhile, PLA1 showed hydrolysis selectivity for phosphatidylcholine and phosphatidylethanolamine, but almost no selectivity for phosphatidylinositol. RLED provided better emulsion stability compared with rice bran lecithin from citric acid degumming (RLCD) and water degumming (RLWD). RLED-stabilized emulsions exhibited smaller particle sizes when deionized water or phosphate buffer were used as the aqueous phase, compared with RLCD and RLWD-stabilized emulsions. RLED, RLCD, and RLWD-stabilized emulsions had similar shear stresses when using phosphate buffer as the aqueous phase, and lower shear stresses when using deionized water. Furthermore, the apparent viscosity was higher when using phosphate buffer as the aqueous phase. Meanwhile, the microstructure of rice bran lecithin-stabilized emulsions corresponded with their particle size distribution and viscosity. This information will help food industry to evaluate the potential applications of RLED.

Special circular hole elements for thermal analysis in cellular solids with multiple circular holes

Abstract: In this paper, a three-dimensional material point human head model is constructed from the computed tomography (CT) scanned images of an adult male volunteer, and used to study the dynamic response of human head under the impact of a three-dimensional cylindrical lead projectile with a speed of 6.4 m/s. The model consists of skull bone, brain tissue and membrane of human head, which is close to the real one. The skull and membrane are modeled by an elastic constitutive model, and the brain tissue is modeled by an anisotropic viscoelastic constitutive model. These constitutive models have been implemented in our three-dimensional explicit material point method code, MPM3D, and is verified by comparing its numerical results for a ball impact problem with those obtained by LS-DYNA. The simulation results help illustrate the response of skull bone, membrane and brain tissues subjected to impact, which contributes to the understanding of the biomechanics and mechanisms of head injury.