QENS investigation of the dynamics of starch saccharides.
We present here quasi-elastic neutron scattering results on D20 hydrated samples of amylose, one of the main saccharide components of starch. Two different sample hydrations (h = 0.5 and 1.0 g D2O (g dry amylose)-1 have been investigated in the temperature range 170 to 350 K. Below 260 K only an elastic contribution is present in the spectra, while a quasi-elastic component shows up above this temperature. The elastic incoherent structure factor (EISF) associated with this component changes considerably with increasing temperature. For the sample with hydration h = 0.5 the confinement volume increases by a factor of four in going from 300 to 350 K, and the proportion of hydrogen involved in the confined diffusion motion increases as well from 30 to 55%. Similar effects are observed at the higher hydration investigated. The observed dynamics can be associated with the known plasticising role of water in polysaccharides.
Dipartimento di Fisica, Università di Parma, Parma, Italy.
M
M
Di Bari
A
A
Deriu
G
G
Albanese
F
F
Cavatorta
D000688:Amylose / Q000737:chemistry*; D002627:Chemistry, Physical / Q000379:methods*; D004058:Diffusion; D004548:Elasticity; D006859:Hydrogen / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D012542:Scattering, Radiation; D013053:Spectrophotometry / Q000379:methods; D013213:Starch / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
D011134:Polysaccharides; D014867:Water; D006859:Hydrogen; D013213:Starch; D000688:Amylose