The objective of the present study was to investigate the structural and rheological properties of octenyl succinic anhydrate (OSA) modified potato starch. Potato starch was modified with different concentrations of OSA (0, 1, 3, and 5%, v/v). X-ray results suggested that OSA modification did not disrupt the crystallinity of the native starch, and esterification occurs primarily in the amorphous regions. The use of 1 H-NMR spectra confirmed the presence of methyl protons in substituted OSA groups, which interacted with the starch molecules. In steady shear rheological analysis, OSA modified starch pastes showed a pronounced shear thinning behavior (n = 0.47-0.54). The consistency index (K) and yield stress (σ oc) values of OSA modified starch pastes were significantly lower than those of the native starch. Dynamic shear rheological tests indicated that OSA modified starch pastes had weak gel-like behavior with storage moduli (G') higher than loss moduli (G''). OSA potato starch pastes were more viscous as compared to the native potato starch paste, as evidenced by their higher tan δ values.

The objective of the present study was to investigate the rheological, pasting, and thermal properties of octenyl succinic anhydrate (DSA)-modified potato starch. Potato starch was modified using different concentrations of DSA (0, 1, 3, and 5%, v/v). The degree of substitution (DS) for the DSA-modified starch ranged from 0.0012 to 0.0055. The amylose leaching values of native and DSA-modified potato starch with different DS levels were in the range of 47.09-87.32%. The gel strength values of the DSA-modified starch were lower than those of native potato starch. Rapid Visco Analyzer data showed that peak, hot pasting, final and setback viscosities of the native starch decreased after DSA modification. Dynamic shear rheological tests, conducted at 4 °C, indicated that DSA-modified potato starch had weak gel-like behavior with the storage moduli (G') higher than the loss moduli (G") over most of the frequency ranges (0.63-63.8 rad·s -1 ).Keywords: potato starch; octenyl succinic anhydride; rheological property; pasting property; retrogradation.Practical Application: Higher stability of DSA-modified potato starch can better withstand freeze-thawing of frozen food.

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