Retrogradation behavior of wheat starch gel affected by natural fermentation

The retrogradation behavior of wheat starch gel influenced by natural fermentation was explored using a rheometer, texture analyzer, low-field nuclear magnetic resonance (LF-NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FITR), and differential scanning calorimetry (DSC). A notable decline in storage modulus (G') and hardness of gels was observed after starch natural fermentation. The T₂₃ value decreased, and the hydrogen proton density increased correspondingly, suggesting that fermented starch gels could retain more water and reduce water migration and loss during retrogradation. SEM images demonstrated that natural fermentation effectively stabilized the microstructure of starch gels during storage. After 168 h of storage at 4 °C, the relative crystallinity (RC), short-range order degree (OD), retrogradation enthalpies (ΔH), and crystallization rate constant (k) of fermented starch gels were significantly reduced compared to those of the non-fermented starch gels. These findings indicated that natural fermentation inhibited the retrogradation of wheat starch. The inhibitory effect was mainly ascribed to the fact that natural fermentation decreased the crystallization rate and prohibited the formation of an ordered structure during retrogradation. Natural fermentation is promised to be an effective approach to inhibit the retrogradation of wheat starch, providing novel insights for producing fermented starch-based products and prolonging their shelf life.