Molecular Dynamics of Soy-Protein Isolate Films Plasticized by Water and Glycerol
Article first published online: 20 JUL 2006
Journal of Food Science
Volume 68, Issue 8, pages 2516–2522, October 2003
How to Cite
Choi, S.-G., Kim, K.M., Hanna, M.A., Weller, C.L. and Kerr, W.L. (2003), Molecular Dynamics of Soy-Protein Isolate Films Plasticized by Water and Glycerol. Journal of Food Science, 68: 2516–2522. doi: 10.1111/j.1365-2621.2003.tb07054.x
- Issue published online: 20 JUL 2006
- Article first published online: 20 JUL 2006
- MS 20030187 Submitted 4/8/03, Revised 6/16/03, Accepted 8/14/03.
- molecular mobility;
- edible film;
ABSTRACT: The effects of water and glycerol on the molecular mobility of a soy-protein isolate (SPI)-based film were investigated using 1H nuclear magnetic resonance (NMR). SPI-films were prepared with different glycerol contents and equilibrated to various levels of water activity (aw). The distributed transverse relaxation of film samples showed 2 distinct components: a solid-like fraction (T2s*) and a liquid-like fraction (T2m*). The peak T2s* values of films with lower glycerol concentration were more sensitive to variation in aw. As aw increased, the change of solid-like to liquid-like fraction was observed in higher glycerol films. As glycerol content increased, a minimum longitudinal relaxation time (T1) occurred at lower aw. Our results suggest that NMR techniques can be used to quantify the plasticizing effects on biopolymer films.