| 摘要 |
Galacturonic acid is produced by reacting enzymes belonging to the pectase and pectolase group with aqueous solutions of pectic substances, causing the resultant liquid to react with a cation exchange resin to remove any calcium, magnesium or the like ions remaining in the liquid, neutralizing the solution with lime or with a mixture of lime with caustic soda or sodium carbonate, concentrating, if necessary, to precipitate the salts, dissolving the precipitated salts in water, causing the solution of said salts to react with a cation-exchange resin and separating the solution of pure galacturonic acid thus obtained. Raw pectic material such as natural beetroot pulps, pomace or commercial pectin may be used as starting materials and it is advantageous to boil the raw material in water and then cool before the enzymatic treatment. Preferred enzymes are polygalacturonases and pectin-methylesterases. When starting from commercial pectins, sulphites, sulphates and antiseptics are removed by passing over anionic and cationic exchange resins. In an example, raw beetroot pulp is boiled in water for one hour, the solution is cooled and then reacted with a pectolytic enzyme for five days, the liquid is separated off and passed over a cation exchange resin, neutralized with lime and soda concentrated and allowed to stand, whereby the sodium-calcium salt precipitates, the latter is filtered off, dissolved in boiling water and passed over a cation-exchange resin, whereby a pure solution of galacturonic acid is obtained. The acid may be separated out by crystallization or the solution may be used as it is. |
