| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject DNA salt having lowered molecular weight, extremely low viscosity even as a high-concentration solution and remarkably improved solubility in water and enabling easy addition to a liquid food by heat-treating a free DNA originating from the soft roe of fish in water and neutralizing the treated product. SOLUTION: The objective DNA salt having lowered molecular weight, extremely low viscosity even as a high-concentration solution and remarkably improved solubility in water and enabling easy addition to a liquid food can be produced by using the soft roe of fish such as salmon as a DNA raw material, heat-treating at 50-90 deg.C for 30min to 2hr, adding an aqueous solution of sodium hydroxide to adjust the pH to >=8, stirring the solution, removing the solid component by centrifugal separation, adding 7% hydrochloric acid solution, etc., to the obtained filtrate to adjust the pH to 1.5, collecting the precipitated free DNA, thoroughly washing with running water, adding 2 times weight of water, heating at 80 deg.C for 30min, allowing the mixture to cool, removing insoluble component by decantation, adding 20% solution of sodium hydroxide to the supernatant to adjust the pH to 7 and freeze-drying the product. |
