Characterizing digestibility of potato starch with cations by SEM, X-ray, LF-NMR, FTIR

Cations can combine with starch and alter its physicochemical characteristics. The addition of cations may influence the in vitro digestion of potato starch. Scanning electron microscopy, X-ray diffraction, low-field nuclear magnetic resonance, and Fourier transform infrared spectroscopy were used to measure the microstructure, relative crystallinity, water distribution, and interaction of potato starch with cations and characterize its digestibility. The results showed that all cations decreased rapidly digestible starch (RDS) at a low concentration but increased the RDS with the addition of cations, especially trivalent cations. However, the resistant starch (RS) had the opposite trend. All cations increased the relative crystallinity of potato starch, except Ca2+. Fe3+, and Al3+ markedly decreased the mobility and hydrogen bonds in potato starch. In general, the addition of cations influenced the retrogradation of potato starch, resulting in a change in its digestibility.