Retrogradation behavior of corn starch treated with 1,4-α-glucan branching enzyme

The retrogradation behavior of corn starch treated with 1,4-α-glucan branching enzyme (GBE) was investigated using rheometry, pulsed nuclear magnetic resonance (PNMR), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Dynamic time sweep analysis confirmed that the storage modulus (G′) of corn starch stored at 4 °C decreased with increasing GBE treatment time. PNMR analysis demonstrated that the transverse relaxation times (T2) of corn starches treated with GBE were higher than that of control during the storage at 4 °C. DSC results demonstrated that the retrogradation enthalpy (ΔHr) of corn starch was reduced by 22.3% after GBE treatment for 10 h. Avrami equation analysis showed that GBE treatment reduced the rate of starch retrogradation. FTIR analysis revealed that GBE treatment led to a decrease in hydrogen bonds within the starch. Overall, these results demonstrate that both short- and long-term retrogradation of corn starch were retarded by GBE treatment.