EFFECTS OF CARBOXYMETHYLATION AND HYDROXYPROPYLATION ON PROPERTIES AND STRUCTURE OF DIFFERENT STARCHES

The effect of carboxymethylation and hydroxypropylation on the properties and structures of potato starch (PS), tapioca starch (TS), sweet potato starch (SPS), pea starch (Ps), waxy corn starch (WCS) and corn starch (CS) was investigated to produce carboxymethyl starch and hydroxypropyl starch, utilize them properly. The results showed that the increase in swelling capacity of different starches caused by carboxymethylation was greater than that caused by hydroxypropylation. The Blue Values of different starches were less influenced by hydroxypropylation, and significantly more affected by carboxymethylation. The starches were affected differently by carboxymethylation, while PS, TS, Ps and CS had the same behavior after hydroxypropylation. Hydroxypropylation increased the average diameter of PS, SPS, Ps and WCS, but lowered the average diameter of TS and CS. Carboxymethylation altered the crystalline structure of WCS and CS. Hydroxypropylation only changed the crystalline structure of PS. Carboxymethylation led to an increase in the thermal stability of different starches, while hydroxypropylation caused reduction in the thermal stability of starches.