Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
604555 | Food Hydrocolloids | 2011 | 7 Pages |
The effects of pH and electrolytes (NaCl and CaCl2) on the viscosity, dynamic modulus (storage modulus G′ and loss modulus G″) and thixotropy of aqueous solution of new exopolysaccharide (SM-A87 EPS) secreted by a deep-sea mesophilic bacterium Wangia profunda SM-A87 were investigated. It was found that at pH 3–12 and the electrolyte concentration of 0.1–80 g/L, the SM-A87 EPS solution showed very weakly pH-dependent and salt-dependent rheological properties and dominant elastic behavior. These properties were considered to arise from the hyper-branched structure of the SM-A87 EPS molecules through the comparison of rheological properties of SM-A87 EPS solutions with those of partially hydrolyzed polyacrylamide ones at different electrolyte concentrations. Such good pH stability and salt resistance of the SM-A87 EPS solution indicate that SM-A87 EPS has great potential for application as food additive, thickener, stabilizer and enhanced oil recovery system. In the studied conditions, 2 g/L SM-A87 EPS solution showed positive thixotropy. The relative thixotropic recovery decreased with pH increasing and the electrolyte concentration decreasing.
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