Sodium alginate pH value and stability
pH value
Water-soluble sodium alginate, insoluble in most organic solvents. It is soluble in alkaline solution, the solution has a viscosity. Sodium alginate powder with water wet, the water particles to the surface of co-operation with the sticky. Then particles bonded together to form clumps quickly, clumps very slowly for complete hydration and dissolution. If the water contains other competition with alginate hydrated compounds, is more difficult to dissolve sodium alginate in water. Water, sugar, starch or protein will reduce the rate of hydration of sodium alginate, it is necessary to extend the mixing time. Monovalent cation salt (as NaCl) in concentrations higher than 0.5% will have a similar effect. 1% sodium alginate solution in distilled water pH of about 7.2.
Stability
Alginate is hygroscopic equilibrium depends on the amount of water contained in the relative humidity. Dry sodium alginate in sealed containers at temperatures below 25 ℃ and stored fairly stable. Sodium alginate solution at pH5 ~ 9 are stable. Degree of polymerization (DP) and molecular weight and viscosity of sodium alginate solution is directly related to storage time can be used to measure viscosity of sodium alginate to reduce the degree of polymerization. High degree of polymerization of the oligomeric heterozygosity less than the stability of alginate sodium alginate. According to reports by the proton-catalyzed hydrolysis of sodium alginate can be, depending on the hydrolysis time, pH and temperature. Propylene glycol alginate solution at room temperature, pH3 ~ 4 are stable; pH less than 2 or greater than 6, even at room temperature will quickly reduce the viscosity.