A molecular dynamic study of the starch obtained from the Mangifera indica Cv. Bourbon and Espada seeds by 13C solid state NMR

Abstract

The molecular mobility of the starch obtained from Mangifera indica Cv. Bourboun and Espada, has been characterised by 13C solid state nuclear magnetic resonance, using techniques, such as magic angle spinning (MAS) and cross polarisation magic angle spinning (CPMAS) NMR and by proton spin-lattice relaxation time in the rotating frame ( T 1 H ρ). The CPMAS 13C NMR spectra of these seeds showed three signals for Bourboun and two very broad signals for Espada. The seeds of the Mangifera indica Cv. Bourboun and Espada are heterogeneous amorphous polysaccharides that present, at least, two domains with distinct molecular mobility. These domains differ in size and chain packing. The variable contact time decay confirms that these starches are amorphous and present one predominant rigid domain. Mango fruits were also analysed by delayed contact time experiments, and the 13C decays showed that the polysaccharides are heterogeneous and contain one rigid domain that controls the relaxation parameter.