Abstract: In order to explore the retardant effect of adding oleic acid and maltitol mixtures on the retrogradation properties of corn starch, rapid viscosity analysis (RVA), differential scanning calorimetric analysis (DSC), texture analysis, dynamic rheological analysis, low-field nuclear magnetic resonance (LF-NMR), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to evaluate the gelatinization, retrogradation, rheological, texture and crystallization structure properties of corn starch gels with different proportions of oleic acid and maltitol mixtures. The results suggested that adding oleic acid and maltitol mixtures could increase the gelatinization temperature, and decrease the setback value and retrogradation rate of corn starch. Upon addition of a 0.5:1.5 mixture of oleic acid and maltitol, the gelatinization temperature was the highest (77.80 ℃), while the setback value was the lowest (1 218 cP). The retrogradation rate of corn starch gels decreased by 60% lower than that of native starch gel. Adding oleic acid and maltitol increased the tangent of loss angle and transverse relaxation time (T2) of corn starch gels, which resulted in the formation of a weak gel structure as well as a reduction in the firmness, short-range order and relative crystallinity of corn starch gels. The 0.5:1.5 mixture had a synergistic effect on retarding the retrogradation of corn starch. These results may be related to the fact that maltitol could inhibit water molecule movement in starch system and that oleic acid could form a complex with starch to prevent the recrystallization of starch. The present study provides a theoretical basis for improving the processing properties of corn starch and the quality of starch-based foods.

Key words: corn starch; maltitol; oleic acid; retrogradation; properties; structure