Preparation and characteristics of carboxymethyl potato starch

The optimum parameters for preparation of carboxymethylated potato starch and its properties were studied.The result of orthogonal experiments showed that the highest DS could be achieved 0.841 5 under the condition as starch solution 16%,mass ratio of chloracetic acid and starch 0.11,mass ratio of NaOH and starch 0.09,temperature at 45 ℃,and reaction time for 6 h.Among the factors,the effect was decreased in the following order:temperaturesodium hydroxidereaction timechloroacetic acid.The carboxymethyl starch had a lower level of the viscosity in strong acid or alkali medium;however,the viscosity kept a higher level in neutral or bias-neutral medium.The viscosity gradually decreased with the temperature increasing.And carboxy methylation significantly improved the transparency of potato starch.