The fractal structure of the aggregates in food protein gels was analyzed. Three kinds of food protein gels were prepared: (1) β-lactoglobulin (β-LG) gel; (2) 11S soybean globulin gel; and (3) caseinate gel. From the concentration dependence of the gel elasticity, the fractal dimensions Df of the aggregates in the gels were evaluated, according to the theory of Shih et al. These gels showed the weak-link behavior described in the theory of Shih et al The values obtained for Df were 2.6-2.7, which were larger than those predicted by the cluster-cluster aggregation model for a dilute system. In addition, for the β-LG gels, the fractal dimension was also evaluated from the analysis of the gel image obtained with a confocal scanning laser microscopy, the value being close to that evaluated from the concentration dependence of the gel elasticity. These results indicate that the elastic behavior of the aggregate gels is a reflection of fractal structure of the aggregates in the gels.
Keywords: aggregate; confocal scanning microscopy; elasticity; fractal; gel.