Insights into the supramolecular structure and techno-functional properties of starch isolated from oat rice kernels subjected to different processing treatments

Oat rice kernels were subjected to decortication (DOR), decortication and enzyme deactivation (DDOR), decortication and cooking (DCOR), as well as combined decortication, enzyme deactivation and cooking (DDCOR). The starch fractions were isolated and their structural features were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, solid-state 13C nuclear magnetic resonance, small angle X-ray scattering (SAXS), and scanning electron microscope. In the cooked oat rice samples (DCOR and DDCOR), in addition to losing a significant amount of the A-type crystalline structure, there was an enhancement in the proportion of V-type crystallinity. The cooking process completely destroyed the periodic lamellar structure of oat starch on the SAXS profile. The Mw values (1.195 × 107-1.459 × 107 g/mol) were in the following order: DOR > DDOR > DCOR > DDCOR. The data was in line with the results for crystallinity, double helix content, degree of order, melting enthalpy, and those obtained for textural parameters, resistant starch content, and bile acid binding capacity.