Structural and nutritional properties of pasta from Triticum monococcum and Triticum durum species. A combined 1H NMR, MRI and digestibility investigation

Two different kinds of pasta, differing in botanical species (Triticum turgidum ssp. durum (cv. Saragolla), vs Triticum monococcum ssp. monococcum (cv. Monlis) and processing were studied to investigate a relationship between starch digestibility -enzymatically determined- and microstructure -MRI determined by T₁ and T₂ relaxation and diffusion (D). MRI experiments (4.7 T) were performed on cooked (11-15-20 min) pasta. Combined with¹H NMR analysis (11.7 T) of the chemical compounds released during cooking, MRI data highlighted different microstructure for the two varieties: significantly shorter relaxation and D suggested a more compact structure for Saragolla. Relaxation showed a biexponential decay for T₁, while a single decay for T₂. To shed light on the MRI results, samples cooked in both water and D₂O were compared, confirming the assumed models and showing up a different hydration level. Digestibility results highlighted a lower starch hydrolysis rate in Monlis. All results suggested the protein network to protect starch granules in Saragolla, so influencing the gelatinization process.