Effect of sodium carbonate on the gelation, rheology, texture and structural properties of maize starch-Mesona chinensis polysaccharide gel

In this study, the effects of sodium carbonate (Na2CO3) on the maize starch (MS)-Mesona chinensis polysaccharide (MCP) gels were evaluated. Na2CO3 significantly accelerated pasting process and decreased viscosity of MS mixtures, however, the paste viscosity was increased with increasing concentration of MCP. Na2CO3 addition resulted in higher G′ of starch gels in the presence of 0.2% of MCP compared with MS-MCP gels. X-ray diffraction spectrum showed that the relative crystallinity of MS was increased by both MCP and Na2CO3 during gelatinization. The gel textural properties were improved in the presence of Na2CO3, and the microstructure of MS-MCP-Na2CO3 consisted of cross distributed bigger pores with thicker pore wall. Confocal laser scanning microscopy (CLSM) confirmed the changes in granular size of MS-MCP as the starch granules tended to swell to the high degree in the presence of Na2CO3. The addition of Na2CO3 lead to the improvement of rheological and textural properties of MS-MCP gels, it suggested that Na2CO3 could apply to the starch-non starch polysaccharide systems as gel-strengthen agent.