| The preparation of glucosamine sulfate(GAS) and its physicochemical property were studied in this paper.Glucosamine sulfate was made from glucosamine hydrochloride by using direct acid hydrolysis, triethylamine, ion exchange chromatography methods. The direct acid hydrolysis was confirmed as the best preparation technology according to the product conversion,and then its technological parameters were optimized. The results showed that optimum conditions were as follows:concentration of sulfuric acid 2-8 mol/L, reaction temperature 40 ℃, concentration ratio of GAH to sulfuric acid 1:3.The antioxidative activity of GAS solution in superoxide anion radical,hydroxyl radical and DPPH radical assay system were determined respectively by using the pyrogallol autoxidation, Fenton and DPPH methods,meanwhile,compared with Vitamin C and analogous derivatives of chitosan,such as glucosamine hydrochloride(GAH), glucosamine (GA), N-acetylglucosamine (NAG) and oligochitosan. Its reducing power was determined as well. The results showed that GAS had certain antioxidation in these assay systems.In the system of O2-·,the antioxidant activities was in the order:Vitamin C>oligochitosan>GA>GAH> GAS>NAG; in the system of ·OH:Vitamin C>oligochitosan> GAH>GA>GAS>NAG; in the system of DPPH-:Vitamin C> oligochitosan> GAS> NAG> GA> GAH. The antioxidant activities of GAS among the three systems was in the order:·OH system> DPPH·system> O2-·system.Their reducing power were in the order:Vitamin C> oligochitosan>GAH>GAS>GA>NAG.Also in this paper the bacteriostasis, hydroscopicity, moisture retentive ability,stability and antianaphylaxis of the GAS were studied. The results showed that the GAS had no bacteriostasis to Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisiae, Aspergillus oryzae and Lactobacillus bulgaricus. GAS had good moisture absorption, moisture retention, thermal stability at 20 ℃～50℃,pH stability at the range of pH 4.0～6.0 as well as the good antianaphylaxis. |
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