Debranching potato starch: synthesis, optimization and thermal property

Effect of particle size of sesbania gum on its modification, structure and performances

Sesbania gum (SG), as an environmentally friendly and resourceful natural polymer, has attracted a lot of attention due to its favorable properties. The size distribution of SG powders was broadened owing to the growth. Therefore, it inevitably resulted in the differences in reaction activity, structure and properties of different SG particles. The results showed that small SG particles exhibited higher reaction activity in cross-linking, carboxymethylation and oxidation than its large counterparts. Compared with those of large SG particles, the sedimentation volume of small SG particles could be reduced by 1.1 mL, while their substitution degree of carboxymethyl groups and aldehyde content could be increased by 0.0824 and 18.11 %, respectively. The swelling capacity, freeze-thaw stability, acid and alkali resistance of small SG particles were greater than those of large SG particles, but their retrogradation was weaker than that of large counterparts. The crystalline degree of small SG particles consisting of more long molecular chains could be reduced by 9.8 % compared to large SG particles. The DSC curve of small SG particles was significantly different from that of large SG particles, while the difference in TGA curves between small particles and large particles was relatively small. The enthalpy change of small SG particle was reduced by 48.4 J/g compared to large SG particles. The peak viscosity, final viscosity, breakdown and setback of tapioca starch were obviously influenced by the addition of small SG particles. And their emulsification stability was also better than large SG particles.

Polyethyleneimine grafted starch nanocrystals as a novel biosorbent for efficient removal of methyl blue dye

In this paper, a novel biosorbent of SNCs-PEI was successfully prepared by grafting polyethylenimine (PEI) onto the starch nanocrystals (SNCs) using glutaraldehyde as a crosslinking agent. The optimal preparation conditions of SNCs-PEI were determined by the orthogonal experiments of the three-factor and three-level, and the SNCs-PEI was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDAX), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The zeta potential of SNCs-PEI was +26.3 mV (pH 7), which had a good adsorption performance for the anionic dye methyl blue (MB). The adsorption kinetics and isotherm of MB by SNCs-PEI were studied. At the temperature of 25, 30 and 35 °C, its maximum adsorption capacity was 337.84, 377.36 and 383.14 mg g^-1, respectively. The adsorption of MB by the SNCs-PEI was a spontaneous and endothermic process according to the thermodynamic analysis.

Cationic oxidized microporous rice starch: Preparation, characterization, and properties

The combination of enzymolysis of compound enzyme, oxidation of sodium hypochlorite, and cationic etherification of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTMA) was selected for the functionalization of rice starch (RS) to better raise the performances. The results showed that the oxidation and etherification could improve the acid and alkali resistance of RS, and enhanced its thermal stability. The crystalline structure of RS was an A-type, the enzymolysis, oxidation, and etherification did not change the structural type, while the crystallinity degree of RS derivatives was all reduced. The enzymolysis, oxidation, and etherification altered the pasting properties of RS, and could effectively decrease the setback and breakdown of RS. The oxidation of sodium hypochlorite not only damaged RS particles containing no micropores, but also destroyed the particles containing the micropores. The enzymolysis and oxidation more seriously destroyed the crystalline region than cationic etherification. The oxidation could increase the enthalpy change of RS, whereas the enzymolysis and etherification decreased its enthalpy change. In addition, the enzymolysis and oxidation could lead to the evident increase in average size of RS. The cationic etherification was able to improve the adsorption of Cu²⁺ on RS, whereas the low oxidation could only slightly ameliorate the adsorption of Cu²⁺ . PRACTICAL APPLICATION: Cationic oxidized microporous rice starch as an adsorbent, slow-release agent, and flocculant will be well used in food, medicine, pesticide, papermaking, waste water treatment, and so on owing to its abundant micropores, anionic groups, and cationic groups as well as small particle size and narrow size range.