Dynamic site heterogeneity in amorphous maltose and maltitol from spectral heterogeneity in erythrosin B phosphorescence

The Effect of Molecular Size on Molecular Mobility in Amorphous Oligosaccharides

“…The applicability of such a dynamic picture to biomolecule glasses is supported by evidence of spectral heterogeneity in Ery B phosphorescence in amorphous dried sugars and sugar alcohols [13][14][15] and in dried proteins 27,46 , indicating that dynamic site heterogeneity may be a characteristic feature of amorphous solid foods and other biomaterials. The Ery B phosphorescence emission bandwidth (Γ), the intensity decay stretching exponent (β), and variations in k TS0 and β across the excitation and emission bands all provide information about dynamic site heterogeneity in these amorphous sugar matrixes.…”

“…The principle is that phosphorescence spectroscopy of triplet probes can examine the slow mobility motions occurring on the milliseconds to seconds time scale in highly viscous glasses and melts. Ery B is a food grade phosphorescence probe which has been found to be very sensitive to the molecular mobility in amorphous sugars [13][14][15][16][17][18][19][20]22,25,26 and proteins 27,28 . By embedding Ery B within the amorphous matrix, we can collect signals from probe molecules that are surrounded by matrix molecules and respond to the slow modes of mobility in local environments.…”

“…The dynamic effect of matrix composition varies depending on the properties of the matrix molecules, the concentration of additive, and the temperature [14][15][16][17][18][19][20] . Composite matrixes composed of sucrose and glycerol 16 , of maltose and maltitol 14 , or of lactose and lactitol 15 , for example, all show lower molecular mobility than the corresponding matrixes composed of the pure sugar, while a sucrose matrix containing added biopolymer, either gelatin 19 , xanthan 20 , amylose, or maltodextrin 21 , displayed higher molecular mobility under some concentration conditions than the pure sucrose matrix. Since all of the additives have higher T g than sucrose, such results cannot be explained by the simple hypothesis that composition modulates matrix molecular mobility solely by modulating matrix T g .…”

Molecular mobility and dynamic site heterogeneity in amorphous lactose and lactitol from erythrosin B phosphorescence

“…The peak frequency shifted to higher energy (blue-shifted) with increasing delay time in both lactose and lactitol; these shifts were approximately linear in time and of consistent magnitude (∼ 200 cm − 1 ) at all temperatures measured from − 10°C to 80°C in lactose and from − 10°C to 45°C in lactitol. All curves were approximately parallel in both sugars; vertical shifts with temperature reflected additional stabilization of the triplet state at higher temperature due to increasing dipolar relaxation rate [33,34,59]. At short time (0.1 ms delay), the spectra reflected emission from all chromophores (weighted by their absorbance and inverse lifetime); at long time (2.5 ms delay), however, the measured spectrum only reflected emission from long-lived chromophores.…”

The effect of salts on molecular mobility in amorphous sucrose monitored by erythrosin B phosphorescence

“…A number of techniques have been used to characterize the properties and mobility of amorphous materials. [4][5][6][7][8][9][10][11][12] We have recently demonstrated that phosphorescence of erythrosin B (Ery B) provides a sensitive indicator of molecular mobility as well as dynamic site heterogeneity in amorphous sugars [13][14][15][16] and proteins. [17][18][19][20][21] Amorphous sucrose is involved in the protection of living organisms, seeds, and spores against stresses induced by desiccation; [22][23][24] it is also the major component responsible for the stability of many dried and frozen foods.…”