The effects of heat–moisture treatment (HMT; moisture content of 25%, at 100°C for 1, 3, or 5 h) prior to octenyl succinylation on degree of substitution (DS), reaction efficiency (RE), FTIR, pasting properties, starch gel morphology, and emulsifying capacity of cassava starch were investigated. Octenyl succinylated heat–moisture treated (OSHMT) starch had higher DS and RE than octenyl succinylated (OS) starch, indicating that prior HMT could enhance the reaction between octenyl succinic anhydride (OSA) and hydroxyl groups of starch molecules. However, the difference between OS and OSHMT starches could not be verified from FT-IR spectra. Paste viscosities of OSHMT starches were higher than native and OS starches, whereas pasting temperature of OSHMT starches was between those of OS and HMT starches. Emulsifying capacity of OSHMT starches was slightly higher than the starch modified by OSA alone.
Cassava starch; Heat–moisture treatment; Octenyl succinic anhydride esterification; Physicochemical properties