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Phase behavior of aqueous gelatin/oligosaccharide mixtures
Author(s) -
Vinches Corinne,
Parker Alan,
Reed Wayne F.
Publication year - 1997
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/(sici)1097-0282(199705)41:6<607::aid-bip2>3.0.co;2-u
Subject(s) - gelatin , chemistry , phase diagram , aqueous solution , kinetics , thermodynamics , phase (matter) , population , oligosaccharide , chromatography , polymer chemistry , chemical engineering , chemical physics , organic chemistry , physics , demography , quantum mechanics , sociology , engineering
The phase behavior of aqueous mixtures of gelatin and oligosaccharides above their gelation temperature is investigated experimentally, and rationalized according to a simple multicomponent Flory‐Huggins model. When the gelatin is only weakly charged, entropic considerations dominate and it is found that the cloud point curve of the mixtures is extremely sensitive to the molecular weight distribution of the oligosaccharide. Even very small quantities of long‐chain oligosaccharides present in an otherwise short‐chain oligosaccharide population can radically reduce the compatibility. Added salt does not significantly affect the phase diagram, although a strong effect on the kinetics of phase separation is seen. Lowering the pH increases the electrostatic charge on the gelatin and strongly enhances the compatibility. Because the kinetics of gelation and phase separation are different, gelation can freeze in nonequilibrium states. Therefore, all phase diagrams were determined well above the gelation temperature (about 37°C). © 1997 John Wiley & Sons, Inc. Biopoly 41: 607–622, 1997