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This study aimed at investing effect of heating treatment, gum concentration and drying temperature on functional properties of farsi gum. For this purpose, solutions with 3, 3.5, 4 and 5% concentration of farsi gum were provided. These solutions were influenced by heat treatments at 65, 75 and 85 °c. Then, they were dried by spray dryer in 120,150, 165 and 180 °c. Results of the studies showed that farsi gum solutions viscosity is intensely depended on heat treatment and drying temperature, in such a way that viscosity decreases linearly as drying temperature and heat treatment increases. Thermal treatment, drying temperature and gum concentration had no significant effect (p<0.05) on the water absorption capacity of farsi gum, but by increasing the drying temperature and increasing of heat treatment, solubility increased. A decrease in drying temperature made improvement in the emulsion ability and emulsion stability of farsi gum but gum concentration had no significant effect on emulsifying properties of farsi gum. The results also showed gum concentration had no significant effect on functional properties which were measured.

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In this study, a numerical model was developed to investigate the two-dimensional heat transfer in a homogenous finite cylinder to predict the local temperature and sterilizing value during caviar pasteurization. A fixed grid finite difference method was used in the solution of heat transfer equations according to Crank-Nicolson’s scheme. The model was validated by comparison of the experimental temperature profiles during caviar pasteurization with the model predicted values (Correlation Coefficient> 0.99 and Root Mean Square Errors< 0.61ºC). The cold spot location was at the radial center between the middle and top of the jar on the vertical axis. For caviar pasteurization, the required heating time for cold spot to reach the desired F-value (= 0.19 min) was 128 minutes at 55°C and 37.63 minutes at 65°C. The results indicated that the developed model could be successfully applied to simulate the caviar thermal processing.

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This study was aimed at evaluating the flow behavior characteristics of yogurt enriched with fish oil (FO) microcapsules prepared by complex coacervation method. FO was microencapsulated in gelatin-acacia gum coacervates. Then, the microcapsules were dried, and yogurt was produced from the milk enriched with microcapsules powder. Rheological characteristics (as measured using a rotational viscometer) of yogurt were evaluated in the shear rate range of 0.262-7.86 s^-1 at 6˚C during 21 days of storage. Power Law model was used for calculation of consistency coefficient and flow behavior index of yogurt. As compared to the control, the enriched yogurt had higher apparent viscosity. Consistency coefficients of the enriched and the control yogurts were in the range of 24.42-28.82 and 15.31-17.76 Pa sⁿ, respectively. Yogurt samples showed a non-Newtonian shear-thinning flow behavior. Addition of FO microcapsules to yogurt may be useful for improving its health-promoting effect and consistency.

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In this research, novel vitamin E loaded Nanostructured Lipid Carriers (NLCs) and Lipid Nanocapsules (LNCs) were produced and their physicochemical properties were characterized. The optimum ratio of liquid to solid lipid and vitamin to total formulations were determined. Particle size, polydispersity index, zeta potential, encapsulation efficiency and encapsulation load of optimum formulations were evaluated. Optimized formulations had encapsulation efficiencies of 95 and 99% for NLC and LNC, respectively. X-ray diffraction results indicated a new crystalline lattice with lower degree of crystallinity for vitamin E nanocarriers in comparison to bulk fats because of curvature effects. Fourier transforms infrared spectroscopy showed that there were no adverse reactions between vitamin E and lipids. Release profile and kinetic modeling were investigated in gastrointestinal media that showed developed nanocarriers can protect vitamin E against acidic condition by decreasing its release in gastric media (release percentage of 29 and 4% for NLC and LNC in gastric media, respectively). Milk was fortified with vitamin E loaded nanocarriers and its sensory evaluation indicated their potential application for production of functional food.

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Doogh, a favorite acidic dairy drink, usually sufferd from low stability and swelling due to microbial activation, protein aggregation and consequently phase separation which happens at low pH. In this study optimization of doogh powder production stabilized by pectin and tragacanth was performed using response surface methodology for selection of appropriate hydrocolloid and processing condition. The results showed that the quality of doogh powder strongly depends upon the spray drying temperature and type of hydrocolloid addition. Optimum operating conditions were found to be an inlet air temperature of 122 ºC and stabilization using tragacanth, under which moisture content, bulk density, solubility, Carr index, serum separation, color (L factor), pH, Hausner ratio, and porosity were 5%, 0.31%, 88%, 37, 65%, 89, 4.33, 1.59% and 73.5%, respectively.  Evaluation of sensory attributes (color, odor, flavor, consistency, and total acceptance) confirmed that there was no significant difference (p>0.05) between dried doogh powder produced in optimized conditions and freshly prepared sample.