Octenyl succinate hydroxypropyl acidolysis tamarind gum: synthesis, optimization, structure and properties

Octenyl succinate hydroxypropyl acidolysis tamarind gum (OSA-HATG) with a high substitution degree of ester groups was first synthesized using hydroxypropyl acidolysis tamarind gum (HATG) as a raw material, 1-butyl-3-methylimidazolium chloride (ionic liquid) as a solvent, octenyl succinic anhydride (OSA) as an acylating agent, and 4-dimethylamino pyridine (DMAP) as a catalyst. The results showed that OSA-HATG, as a new emulsifier, has good emulsification capacity and stability. The emulsifying capacity of OSA-HATG increased with increasing substitution degree. Acidolysis (acid hydrolysis) and hydroxypropylation were mainly conducted on the large particles of TG. The stretching vibration peaks of the C=O bonds at 1735 cm −1 and C=C bonds at 1654 cm −1 indicated that the acylation of HATG by OSA was successfully accomplished. TG was almost amorphous. The acylation resulted in a reduction in the thermal stability of OSA-HATG but obviously increased the contact angle of OSA-HATG (102.7°). The addition of TG and its derivatives did not improve the setback of potato starch. The acidolysis and hydroxypropylation could swell the TG particles.