Physicochemical properties of octenyl succinic anhydride-modified potato starch with different degrees of substitution

BACKGROUND: Esterified starch is an important type of modified starch. In particular, octenyl succinic anhydride-modified starch (OSA starch) is widely used in the food industry. However, there has been little research on the properties of products with different degrees of substitution (DS). Therefore the aim of this study was to analyse the physicochemical properties of products with different DS. RESULTS: OSA starch samples with different DS were prepared from potato starch. Two new peaks were observed in the Fourier transform infrared spectrum, one at 1724 cm(-1) due to C=O and one at 1572 cm(-1) due to RCOO-. Emulsifying capacity and emulsion stability improved with increasing IDS. Rheological analysis showed the occurrence of the 'shear-thinning' phenomenon, the viscosity of the sample with DS = 0.0211 being even lower than that of native starch. A decrease in syneresis rate from 88.3% (native starch) to 39.0% (DS = 0.0211) indicated that freeze-thaw stability was improved. CONCLUSION: The physicochemical properties of OSA potato starch were better than those of native potato starch. Freeze-thaw stability, emulsifying capacity and emulsion stability improved with increasing DS. Viscosity increased at lower IDS but decreased at IDS = 0.0211. (C) 2009 Society of Chemical Industry