Filler Effects of Oil Droplets on Physical Properties of Emulsion Gels
Filler effects of oil droplets on viscoelastic properties of emulsion gels were investigated by small deformation mechanical measurements. Emulsions were made with soya oil and soy l1S globulin(15 wt % oil, 1.5 - 7 % protein concentrations). Emulsions and soy 11S globulin solutions were gelated by Ca++-independent transglutaminase from microorganism. The shear storage modulus (G’) and loss modulus (G”) of proteinous gels and emulsion gels depended on the protein concentration. The concentrate-dependence of modulus was approximately by an exponential function of the form G ∞ cn, in which n=4 and n=2 was found in the case of the proteinous gel and the emulsion gel, respectively. Shear moduli of emulsion gels were much higher than those of proteinous gels. The gel made from fine emulsion (containing smaller size oil droplets) exhibited higher G’ and G” than the gel from coarse emulsion. Addition of Tween 20 was found to reduce G’ and G” of emulsion gel even if the protein matrix is not significantly displaced from the oil-water interface by the surfactant.
KeywordsFiller Effect Viscoelastic Parameter Coarse Emulsion Shear Storage Modulus Lysine Isopeptide Bond
Unable to display preview. Download preview PDF.
- 1.K.R. Langley, M.L.Green, and B.E.Brooker, Mechanical properties and structure of model composite foods, in:“Food Polymers, Gels and Colloids”, E.Dickinson, ed., Royal Society of Chemistry, London, (1991).Google Scholar
- 4.M. Yoshida, K.Kohyama and K.Nishinari, Gelation properties of soy milk and soybean 1 IS globulin from Japanese -grown soybeans, Biosci. Biotech. Biochem., 56: 735 (1992).Google Scholar
- 5.N. Hirai, The gel elasticity of high polymers, Bull. Inst. Chem. Res. Kyoto Univ., 33: 21 (1955).Google Scholar
- 7.A.H. Clark, S.B.Ross-Murphy, K.Nishinari and M.Watase, Shear modulus-concentration relationships for Biopolymer gels. Comparison of independent and cooperative crosslink descriptions, in: “Physical networks. Polymer and gel”sW.Burchard and S.B.Ross-Murphy, ed., Elsevier Applied Science, London, (1990).Google Scholar