Background and Objectives: Problemsof poor organoleptic and physicalproperties of low fat cheese suggest the use of some hydrocolloids in providing the desirable qualities of these types of cheeses.To improve the characteristics of low fat cheese, several studies have been used polysaccharides as fat replacers.In this study, for improving the characteristics of low fat Iranian white cheese, gum tragacanth (Astragalus Parrowianus) was added to the low fat cheese milk in two level (0.05 and 0.1% (w/w).
Materials and Methods: Changes in physicochemical, textural, sensory and microstructural properties of cheese samples in day 1 and 60 of ripening time were evaluated and a comparison between cheese samples containing gum and blank samples (full fat and low fat cheeses) was carried out. For better investigation of interactions between protein and polysaccharide in cheese matrix, FTIR method was used.
 Results: Addition of gum tragacanth into low fat cheese matrix resulted in a better texture and structure and could relatively imitate the full fat cheese characteristics. Incorporation of this gum caused some changes in FTIR spectra of low fat cheese. Ripening time also influenced the FTIR spectra of cheese samples.
Conclusion: Incorporation of gum tragacanth into low fat Iranian white cheese, can improve its textural, sensorial and microstructural characteristics. FTIR can be a proper instrument for precise studying of protein matrix of cheeses.