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Background and Objectives: High fat consumption has been shown to be associated with an increased risk of diseases, such as obesity, atherosclerosis, coronary heart disease, high blood pressure, and tissue injury diseases associated with lipid oxidation. Increased public awareness of this subject had led to a dramatic increase in the demand for low-fat foods. Dairy products are becoming one of the most widely consumed low-fat food group. Recently, a significant increase has been observed in the consumption of low–fat cheese. Iranian white-brined cheese has 18-20% fat content. In this study, we have evaluated the effects of two hydrocolloid–Guar gum and Arabic gum –as fat-replacers, on the physicochemical and rheological properties of low-fat white-brined cheese. Materials and Methods: Using an industrial method, samples of Iranian white-brined cheese in 3 levels of milk fat (0.4%, 0.9%, and 1.4%) were prepared from cow's milk at a small scale. The effects of 4 levels of Guar gum (0, 75, 150, and 300 ppm) and 3 levels of Arabic Gum (0, 150, and 300 ppm) in samples on chemical (dry matter, fat content, ferry fatty acid, salt, and acidity) and rheological (storage modulus) properties of the cheeses were evaluated using the Response Surface Methodology. Results: The effects of reducing the fat content of cheese and the use of the two hydrocolloids on the chemical and rheological attributes were evaluated by response surface and contour plots, and the full-term second-order polynomial response surface models were fitted to each of response variables. Then, based on the rheological properties of Iranian white-brined cheese, optimum points of low-fat Iranian white-cheese production were obtained. Conclusion: Arabic Gum at concentrations higher than 150 ppm, caused an increase in the storage modulus, therefore an undesirable hardness in texture of low-fat cheeses was obtained. By increasing the concentration of guar gum, the storage modulus and stress at the fracture point were decreased. It is concluded, that by using guar gum as a fat replacer in the manufacturing of low-fat cheese, an improvement in the texture of product can be obtained.

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Background and Objectives: Aloe Vera is native to tropical and subtropical regions and considering the combined assets of its active constituents, as a plant has long been used to treat various diseases. In this study the effect of different concentrations of Aloe Vera Gel on qualitative characteristics and viability of probiotic bacteria in Dough was studied.
 Materials & Methods: Different percentages of Aloe Vera Gel (0, 5, 10, 15 and 20 percent)  were added to probiotic Dough and was placed in refrigerator. The relevant test was carried out in three cycles of 10 days on the dough. Sensory evaluation was carried out one day after production and again after twenty-eight days following production  by a team of 10 trained raters in terms of sensory properties (color, odor, flavor, texture and taste). Serum Separation of samples were measured. Probiotics counting was done on MRS agar medium. Rheological tests were done a day after preparation at 2/0 ± 10 ° C using a Rheometer with concentric cylinder geometry.
Results: Increasing the percentage of Aloe Vera Gel had no significant effect on odor and color, but the texture and overall acceptability was significantly affected. It also reduced serum separation percentage. The number of living cells of probiotic bacteria in all samples significantly decreased with time. Generally, concentrations of 10% Aloe Vera had the highest survival rate of probiotic bacteria in all storage times and at the end of storage contained 3.1 ± 0.3× 10⁷ CFU / ml   Lactobacillus acidophilus and the 1.2±0.2×10⁷ CFU/ml  Bifidobacterium animalis. Viscosity decreased with increasing shear rate, which was evident in  samples containing 10 and 20 percent aloe vera Gel compared to control and other samples containing gel.
Conclusion: According to the results of different concentrations of Aloe Vera on qualitative  and sensory properties of probiotic Dough, 10% concentration was chosen as the most suitable concentration.