In the present study 20 reduced fat and egg mayonnaise samples were produced with different levels of three fat replacers (xanthan, guar and pregelatinized corn starch) and egg/soy milk mixture as egg alternative. Different characteristics including rheological parameters, particle size distribution, stability, thermal stability and color parameters were characterized and optimized by response surface method through central composite design in order to investigate the performance of employed hydrocolloids along with soy milk. Rheology revealed non-Newtonian and shear thinning behavior for all samples and in contrast to pre gel corn starch, xanthan and guar increased shear thinning behavior. In addition, synergistic interaction between xanthan and pre gel corn starch and also between xanthan and guar was found by data analysis. Xanthan produced larger droplet size probably due to its negatively-charged structure through adsorption at the interface coated by positively-charged soy proteins or by bridging mechanism. Food hydrocolloids, used in this study, were found to be significantly effective in most of the responses. From the data achieved in this study, it can be concluded that because of capability of xanthan and pre gel corn starch in changing physico-chemical parameters, individually or synergistically, they can be used in production of mayonnaise and other food formulations as fat replacer, thickener and stabilizer.

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