Abstract
The relation between molecular structure of oil-structuring agents and their gel-forming capability was investigated for mixtures of the phytosterol ester γ-oryzanol with a series of phytosterols. Dihydrocholesterol, cholesterol, β-sitosterol, and stigmasterol were found to form firm transparent gels with γ-oryzanol in sunflower oil under the conditions used in this work. The mixture of β-sitosterol with γ-oryzanol in sunflower oil does not gel immediately on cooling, but mechanical agitation such as shear promotes gelling. Gels that are formed immediately after cooling show a higher modulus than gels for which there is a time delay between cooling and agitation (150 vs. 100 kPa). The effect of oscillatory shear parameters (amplitude, frequency) is small, as long as the yield stress of the gel is not exceeded. The gels withstand compression very well (up to deformations of 10%), but yield at very small deformations. The enthalpy of melting of the solid phase is estimated to be 26±4 kJ/mol, putting it in the same range as for certain fibrillar steroid-derived organogels.
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de Bruijne, D.W., and A. Bot, Fabricated Fat-based Foods, in Food Texture—Measurement and Perception, edited by A.J. Rosenthal, Aspen, Gaithersburg, 1999, pp. 185–227.
Bot, A., E. Flöter, J.G. Lammers, and E.G. Pelan, Controlling the Texture of Spreads, in Texture in Foods, Volume 1: Semisolid Foods, edited by B.M. McKenna, Woodhead, Cambridge, 2003, pp. 350–372.
Clark, A.H., and S.B. Ross-Murphy, Structural and Mechanical Properties of Biopolymer Gels, Adv. Polym. Sci. 83:57–192 (1987).
te Nijenhuis, K., Thermoreversible Networks: Viscoelastic Properties and Structure of Gels, Adv. Polym. Sci. 130:1–235 (1997).
Gandolfo, F.G., A. Bot, and E. Flöter, Structuring of Edible Oils by Long Chain Fatty Acids, Fatty Alcohols and Their Mixtures, J. Am. Oil Chem. Soc. 81:1–6 (2004).
Ritter, H., R.L.K.M. van de Sande, and V.K. Müller, Liquid Fatty Component Containing Composition, Patent Application WO 97/42830 (1997).
Ojijo, N.K.O., E. Kesselman, V. Shuster, S. Eichler, S. Eger, I. Neeman, and E. Shimoni, Changes in Microstructural, Thermal, and Rheological Properties of Olive Oil/Monoglyceride Networks During Storage, Food Res. Int. 37:385–393 (2004).
Ojijo, N.K.O., I. Neeman, S. Eger, and E. Shimoni, Effects of Monoglyceride Content, Cooling Rate and Shear on the Rheological Properties of Olive Oil/Monoglyceride Gel Networks, J. Sci. Food Agric. 84:1585–1593 (2004).
Daniel, J., and R. Rajasekharan, Organogelation of Plant Oils and Hydrocarbons by Long-Chain Saturated FA, Fatty Alcohols, Wax Esters, and Dicarboxylic Acids, J. Am. Oil Chem. Soc. 80:417–421 (2003).
Flöter, E., and A. Bot, Developing Products with Modified Fats, in Improving the Fat Content of Foods, edited by C.M. Williams and J. Buttriss, Woodhead, Cambridge, 2006, pp. 411–427.
Wade, R.H., P. Terech, E.A. Hewat, R. Ramasseul, and F. Volino, The Network Structure of a Steroid Cyclohexane Physical Gel, J. Colloid Interface Sci. 114:442–451 (1986).
Terech, P., and R.H. Wade, The Relationship Between a Dried and Native Steroid Gel, J. Colloid Interface Sci. 125:542–551 (1988).
Lin, Y.C., and R.G. Weiss, A Novel Gelator of Organic Liquids and the Properties of Its Gels, Macromolecules 20:414–417 (1987).
Lin, Y.C., B. Kachar, and R.G. Weiss, Novel Family of Gelators of Organic Fluids and the Structure of Their Gels, J. Am. Chem. Soc. 111:5542–5551 (1989).
Murata, K., M. Aoki, T. Nishi, A. Ikeda, and S. Shinkai, New Cholesterol-Based Gelators with Light-Responsive and Metal-Responsive Functions, J. Chem. Soc., Chem. Commun.: 1715–1718 (1991).
Murata, K., M. Aoki, and S. Shinkai, Sol-Gel Phase Transition of Switch-Functionalized Cholesterols as Detected by Circular Dichroism, Chem. Lett.: 739–742 (1992).
Terech, P., I. Furman, R.G. Weiss, H. Bouas-Laurent, J.P. Desvergne, and R. Ramasseul, Gels from Small Molecules in Organic Solvents: Structural Features of a Family of Steroid and Anthryl-Based Organogelators, Faraday Discuss. 101:345–358 (1995).
Terech, P., D. Pasquier, V. Bordas, and C. Rossat, Rheological Properties and Structural Correlations in Molecular Organogels, Langmuir 16:4485–4494 (2000).
Brinksma, J., B.L. Feringa, R.M. Kellogg, R. Vreeker, and J. van Esch, Rheology and Thermotropic Properties of Bis-Urea-Based Organogels in Various Primary Alcohols, Langmuir 16:9249–9255 (2000).
Terech, P., Low-Molecular Weight Organogelators, in Specialist Surfactants, edited by I.D. Robb, Blackie Academic and Professional, Glasgow, 1997, pp. 208–268.
Bot, A., I.A. van Amerongen, R.D. Groot, L.L. Hoekstra, and W.G.M. Agterol, Large Deformation Rheology of Gelatin Gels, Polym. Gels Networks 4:189–227 (1996).
Narine, S.S., and A.G. Marangoni, Mechanical and Structural Model of Fractal Networks of Fat Crystal at Small Deformations, Phys. Rev. E 60:6991–7000 (1999).
Hildebrand, J.H., and R.L. Scott, Regular Solutions, Prentice-Hall, Englewood Cliffs, NJ, 1962, pp. 21–23.
Gandolfo, F.G., A. Bot, and E. Flöter, Phase Diagram of Mixtures of Stearic Acid and Stearyl Alcohol, Thermochim. Acta 404:9–17 (2003).
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Bot, A., Agterof, W.G.M. Structuring of edible oils by mixtures of γ-oryzanol with β-sitosterol or related phytosterols. J Am Oil Chem Soc 83, 513–521 (2006). https://doi.org/10.1007/s11746-006-1234-7
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DOI: https://doi.org/10.1007/s11746-006-1234-7