Crystallization from Concentrated Sucrose Solutions
When concentrated aqueous solutions of sucrose are cooled, ice or sucrose crystals separate, depending on the concentration and temperature. The state diagram of the sucrose-water system describes both the equilibrium and non-equilibrium behaviour. A detailed account is given of the effect of sucrose concentration and various, principally polysaccharide, stabilizers on the processes of homogeneous and heterogeneous nucleation, as well as the kinetics of crystal growth. Increasing concentrations of sucrose reduce the diffusion coefficient of water molecules and the linear growth velocity of ice crystals. Polysaccharide stabilizers have relatively little effect until incipient gelation occurs. Thereafter, there is a gross change in crystal form and growth rate. A careful analysis of the impact of sucrose concentration on the rate of ice crystal growth has not permitted satisfactory matching of theoretical predictions with actual behaviour.
Recent studies of the rate of growth of sucrose crystals in sucrose glasses of varying water contents are recorded. There is no simple relationship between the moisture content (in the 2–12 w/w% H2O range) and the rate of growth of the sucrose crystals.
KeywordsSucrose Solution Sucrose Concentration Crystal Growth Rate Vary Water Content Sucrose Crystal
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- 2.A.H. Muhr, “The Influence of Polysaccharides on Ice Formation in Sucrose Solutions,” Ph.D. Thesis, Nottingham University (1983).Google Scholar
- 3.B. Luyet and D. Rasmussen, Study by differential thermal analysis of the temperature of instability of rapidly cooled solutions of glycerol, ethylene glycol, sucrose and glucose, Biodynamica 10:167 (1968).Google Scholar
- 5.H. Levine and L. Slade, Water as a plasticizer: physicochemical aspects of low-moisture polymeric systems, in “Water Science Reviews,” Vol. 3, F. Franks, ed., Cambridge University Press, Cambridge (1988).Google Scholar
- 7.P.V. Hobbs, “Ice Physics,” Clarendon Press, Oxford (1974).Google Scholar
- 9.G.P. Ivantsov, Growth of spherical and needle shaped crystals of a binary alloy, Dokladv Akad. Nauk. SSSR 58:567 (1947).Google Scholar
- 11.M.E. Glicksman, R.J. Schaefer, and J.D. Ayers, Dendritic growth — a test of theory, Met. Trans. 7A:1747 (1976).Google Scholar
- 13.J.S. Langer, Dendritic solidification of dilute solutions, Physico-Chemical Hydrodynamics 1:44 (1980).Google Scholar
- 15.N.J.H. Huige and A.A.C. Thijssen, Rate-controlling factors of ice crystal growth from supercooled water and glucose solutions, Proc. of Symp. Inst. Chem. Eng.: 69 (1969).Google Scholar
- 16.A.H. Muhr and J.M.V. Blanshard, Effect of polysaccharides on the rate of growth of ice, J. Food Technol. 21:683 (1986).Google Scholar
- 20.G.W. Greenwood, Mechanism of phase transformations in crystalline solids, Inst. Metals Monograph Series 33:103 (1969).Google Scholar
- 21.J. Fischmeister and G. Grimvall, Ostwald ripening — survey, Material Sci. Res. 6:119 (1973).Google Scholar