Effect of Exopolysaccharides-producing Starter Culture on the Flavor Profile and Characteristics of Low Fat Ras Cheese

BACKGROUND AND OBJECTIVE: The application of the exopolysaccharide-producing starter culture for improving the texture and technical properties and evaluating flavor profile of low-fat Ras cheese was studied. The experimental design was performed to compare flavour compounds of traditional and exopolysaccharide producing starters (EPS) for different levels of fat milk cheese. MATERIALS AND METHODS: Control (4% fat) with traditional starter, T1 (0% fat) with EPS, T2 (1% fat) with EPS), T3 (2% fat) with EPS and T4 (3% fat) with EPS were used. The physicochemical, textural profile analysis and organoleptic properties of fresh and stored cheeses (4 months) were determined. Also, the microscopic structural changes in fresh low-fat Ras cheese with EPS were evaluated. RESULTS: The results indicated that addition of EPS producing cultures with decreasing fat of cheese milk lead to an increase in the moisture of treatments as well as hardness, cohesiveness, springiness, chewiness and gumminess of the resultant cheese. The data indicated that control cheese (full-fat and without EPS-producing cultures) had the lowest values of acidity. The changes in pH values among all cheese treatments and during storage period followed opposite trend to that of titratable acidity. There were negative correlation between the rate of fat reduction and the values of SN (soluble nitrogen). CONCLUSION: Addition of EPS-producing cultures in Ras cheese milk improved sensory evaluation of resultant cheese, whereas cheese with 3% fat and EPS-producing culture (T4) selected as best Ras cheese sample.