The present invention relates to technical field of
modified starch and provides physical oxidative carboxymethyl composite
modified starch and a preparation method thereof. The
modified starch is prepared from the following raw materials: raw
starch,
alcohol, inorganic alkali,
sodium chloroacetate,
hydrochloric acid and
hydrogen peroxide. According to the carboxymethyl composite modified
starch provided by the invention, the process steps of firstly mechanically activating the raw
starch, etherifying the carboxymethyl and then carrying out
hydrogen peroxide oxidation are adopted; therefore, the proportion of
alcohol and water in a carboxymethylation reaction segment
system can be favorably controlled to avoid expansion and
dissolution of starch granules, so as to ensure high substitution ratio of the prepared product; in addition, due to the
process operation of first etherification and then oxidation, the product
viscosity can be controlled more accurately. The preparation method of the carboxymethyl composite modified starch provided by the invention can be used for preparing
carboxymethyl starch with high substitution ratio and low
viscosity by using mechanically activated corn, cassava and waxy
maize starch as raw materials, the operation is convenient, the process flexibility is strong, the continuity is good, the
utilization rate of equipment is high and the production efficiency is high.