Papers by Keyword: Porous Starch

Abstract: This study was carried out to investigate the effects of hydrolysis ratio on the structure and adsorption properties of porous starch. The starches with different hydrolysis ratios were prepared by enzymolysis (combination of α-amylase and glucoamylase), and its adsorption capacity was evaluated by using methylene blue (MB) and soybean oil as adsorption objects. The results suggest that crystallinity, specific surface area and adsorption capacity of porous starch were gradually improved with the increase of hydrolysis degree. The crystallinity of native starch was increased by enzymolysis from 28.43±0.23% to 34.70±0.69%, and the specific surface area was increased from 0.58±0.002 m²/g to 1.82±0.014 m²/g. Moreover, the adsorption capacity toward (MB) was increased from 2.88 mg/g to 3.87 mg/g at 25°C, which was accurately described by the pseudo-first-order kinetic model, and the oil absorption ratio was also greatly improved from 23.2±0.16% to 76.1±0.11%. Thus, the properties of porous starch can be adjusted by controlling the hydrolysis ratio to meet different needs in the market.

Abstract: The porous starch was modified by xanthates, and the starch/natural rubber composite was prepared by blending the modified starch with natural rubber latex. The morphology, thermal stability, swelling behavior and mechanical properties of the composite were investigated. Morphology studies by SEM showed that the modified porous starch were homogeneously dispersed in NR matrix. The composite has higher solvent resistance and lower water resistance after adding modified porous starch. The mechanical properties of composite are improved significanly with the increase of modified porous starch.

Abstract: Magnetic carbon spheres (MCSs) with hierarchical pore structure were designed and controllably synthesized using corn starch as carbon source and iron nitrate as metal source by a combined procedure of enzymolysis, pre-oxidation and catalytic carbonization. The results show that after enzymolysis, the porous starch precursor inherits the morphology of original starch with round shape and has a number of honeycomb-like pores of ca.1 μm on the outside surface. It has been found that the MCSs materials with hierarchical porous structure can be synthesized only from the pre-oxidized porous starch by the catalytic carbonization technique, evidenced that the pre-oxidation of carbon source is a dominating factor governing the formation of MCs with hierarchical pore structure. Compared with the porous starch, the pores on the surface of the MCSs shrink slightly and vary in a range of 0.3-0.6 μm.

Abstract: The porous nanocomposites consisting of starch and sepiolite were prepared by a solvent exchange technique, i.e. replacing ice crystals in frozen sepiolite/starch gel with ethanol. The influence of sepiolite contents on pore size, apparent density, moisture adsorption, oil adsorption capacity and dye adsorption of porous sepiolite/starch composites (SPPSs) was investigated. The addition of sepiolite reduced pore size, apparent density and moisture adsorption of SPPSs. The oil adsorption and the methylene blue adsorption of SPPSs could respectively reach 10.1 g/g and 2.07 mg g-1 at the maximal, while those of PS were only 5.83 g/g and 1.55 mg g-1.

Abstract: Porous starch as a kind of high efficiency, non-toxic and safe new organic adsorbents are extensively used in food, medicine, agriculture, cosmetics, paper and other industries. Recently the preparation method is amylase in starch gelatinization temperature of less than hydrolysis. In the conditions of ultrasound (physics) and microwave (electromagnetic fields), we could improve the yield of the traditional method of enzyme hydrolysis corn starch. First, the results show that: the time at 45 min, microwave power 150W, ultrasonic power 400W, temperature 56°C, α-amylase enzyme quantity 8 U/g, glucoamylase and α-amylase ratio 6:1, citric acid buffer liquid pH 5.4, the absorption rate of porous starch is best. Ultrasonic- microwave improves the quality of customary enzymatic hydrolysis starch, by SEM observation, found that: There are a lot of table face holes which are uniform pore density, particle more complete.

Abstract: Rice, maize and potato starches were hydrolyzed by amylase to obtain porous starches as final product. The adsorptive capacity, desorbed rates, degree of crystallinity and retrogradation properties of native and porous starches were investigated. The results showed that porous starches had the stronger adsorptive capacity and slower desorbed rate compared with native starches. In the three starch materials, the adsorptive capacity of rice starch for liquids was the strongest; the adsorptive capacity of potato starch for liquids was the weakest. the more flavors adsorbed, the more flavors desorbed. X-ray diffraction showed that Enzyme hydrolysis did not result in any significant changes in the degree of crystallinity of starch. The porous starches exhibited lower tendency of retrogradation as assessed by differential scanning calorimetry (DSC).