The effect of enzymatic pretreatments on subsequent octenyl succinic anhydride modifications of cornstarch

Cornstarch granules were allowed to react with α-amylase and then esterified with octenyl succinic anhydride (OSA). The paste properties and the distribution of octenyl succinate (OS) groups of OS-starch granule were studied. Results show that the α-amylase pretreatments significantly decreased the degree of substitution (DS) of OS-starch compare with a non-pretreated control group, while the retrogradation properties, freeze-thaw stability and shearing resistant stability of α-amylase pretreated OS-starch didn't change markedly. Enzymatic pretreatment appears to influence the distribution of the OS groups from being mostly on the surface and amorphous part of the starch granules to being in the inner amorphous and crystalline regions of the granules, as shown by X-ray photoelectron spectroscopy (XPS) and lintnerisation studies.

The cornstarch granule was pretreated by a-Amylase and then esterfied with octenyl succinic anhydride (OSA). The function-structure relationship between paste properties and octenyl succinate group distribution in amorphous/crystalline and surface/inner region of enzymatic pretreatments OS-starch granule was studied.