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In this research, the rheological behavior of ribbon type Iranian gum tragacanth was investigated at different concentrations (1–5 g/L), temperatures (5–55°C with 10 degree intervals), pH (4, 7, and 10), and rotational speeds (up to 200 rpm). At first, the apparent viscosity of gum tragacanth solutions were measured at 3 concentrations (1, 3, and 5 g/L) during 28 hours in 2 hour intervals. The results showed that the soaking has no significant effect on the apparent viscosity of gum tragacanth solutions. Regarding the influence of the abovementioned factors, our findings revealed that increasing rotational speed or shear rate at low concentrations (1 and 2 g/L) has no effect on the apparent viscosity of the solutions and those samples behaved likewise Newtonian fluids whereas, at higher concentrations (3 to 5 g/L), with increasing the rotational speed the apparent viscosity diminished and the solution consequently showed a Pseudoplastic behavior. In all experiments, alongside increasing the concentration and temperature the apparent viscosity increased and decreased, respectively. In addition, pH had no considerable effect on apparent viscosity in most of our samples. For comparison purposes, using mathematical equations, experimental findings (namely rotational speed) were converted to fundamental parameters (shear rate and shear stress) as well.

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Carboxymethyl cellulose (CMC) and tragacanth gums at 0.5 and 1% levels % were added to the fish balls from silver carp to improve the its texture and sensory characteristics. The proximate composition, physical factors (batter pick-up, product yield, shrinkage and oil absorption reduction), sensory analysis and textural properties of fried balls were compared with the control treatment. All treatments showed less fat and oil absorption rate (p> 0.05) compared to the control treatment. Treatment containing 1% tragacanth gum showed the highest levels of wet, lightness, hardness and springiness, while treatment containing 1% CMC showed the highest product yield and lowest amounts of expressible water, fat, lightness, oil absorption and springiness (p>0.05). Overall, the performance of tragacanth gum on the texture characteristics was more desirable than CMC gum. All textural index decreased in treatments containing 1% gum. Hence, the use of low levels of the gums is recommended.

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Mayonnaise as an oil in water emulsion with pH<4.1 is one of the oldest man-made emulsions that one of the most widely used sauces in Iran and in the world. Nowadays, gums are widely used to increase stability and also changing the rheological properties of mayonnaise. Gum tragacanth as a plant exudation is an Iranian native gum that it indicates a high viscosity in acidic conditions. Though, it is proved that the gum obtained from different species of Astragalus have an absolutely different physico-chemical properties. So far no comprehensive research has ever been done on the effect of different species of gum tragacanth on the rheological properties of mayonnaise sauce. In this research it was attempted  to study  the effect of gum tragacanth obtained from  two  different  species  of  Astragalus  gossypinus or  Ag and  Astragalus  rahensis  or Ar  on  the flow  and  oscillatory  rheological  properties of mayonnaise  and was determined  the effect  of gum  concentration and temperature on the mentioned  properties. Finally, it was compared with the commercial sauce prepared by using imported gums. The mixture was stirred for 11 min by a rotary mixer at 1000 Rpm. pH and stability tests were done. A comparison of microstructure of the mayonnaise sauce produced with different concentrations of two species of Gum tragacanth was conducted with a light microscopy equipped by a camera. Steady flow and viscoelastic properties were determined by using a controlled shear rate Rhometer. It was shown that all treatments (type of gum and its concentration) had significant on oscillatory rheological properties. After determining the Herschel Bulklley model to describe experimental data's steady rheological tests. It was shown that the mentioned rheological factors had a significant on some of these parameters and apparent viscosity of mayonnaise sauce. A comparison of prepared mayonnaise sauce with two species of Gum tragacanth in different conditions with commercial mayonnaise sauce showed that all factors in every specific level just can make close some characteristic of produced mayonnaise to commercial sample. So the study about the effect of using mixture of different species of Gum Tragacanth with each other or with the other gums on quality of mayonnaise sauce is suggested.

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Due to disadvantages of synthetic packaging materials such as migration into food, polluting of environment, difficulty of recovery, high costs of raw materials and production, also modifying properties of starch based edible film, in this study different kinds of edible films from starch and tragacanth (Iranian gum) will be formulated and their properties investigated.  In this regard, edible films formulated by mixing potato starch, tragacanth (1-5%), Glycerol plasticizer (10-40%) and sunflower oil (0-20%), then the film mechanical (tensile strength and elongation), optical, solubility and water vapor permeability (WVP) properties measured. The results showed that physical and mechanical properties of potato starch-based edible films were affected by the content of tragacanth, glycerol and sunflower oil. The tragacanth gum increased tensile strength and reduced chroma, while glycerol reduced tensile strength and increased elongation at break. Also, the sunflower oil decreased solubility and water vapor permeability and increased elongation. Finally, amounts of 2% tragacanth, 30% glycerol and 17% sunflower oil were determined as optimum points for production of starch based edible films with optimum properties.  

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In this research, different amounts of gum tragacanth (0.5%, 1%, 1.5% and 2% w/w) was added to wheat flour and its effects on bread quality parameters including moisture, specific volume, crumb firmness, color, water activity and bread staling during storage was evaluated. The results suggested that addition of gum tragacanth increased moisture but decreased crumb firmness, loaf volume and specific volume in all samples with reference to the control sample. Measurement of crust and crumb color showed that addition of gum tragacanth at all concentrations significantly decreased lightness of crust and crumb but increased red- and yellowness of both crust and crumb (p  

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Sponge cake is one of the cereal products which has a shelf-life about 4 weeks and contains 15 to 25 % fat. Moisture migration and staling are of most problems related to this product leading irreversible changes in its physical and sensorial properties and finally diminished shelf-life. In this study the effects of tragacanth addition on quality properties and staling pattern in order to improve the quality of cake and increase its shelf-life was investigated. Hence, cakes containing different concentration of tragacanth were prepared and then their volume index, sensory attributes, and physical properties (softness using the texture analyser) were determined. Results showed that cakes contained up to 0.4 % tragacanth had significantly more volume index, softer texture, and better sensory attributes than the reference cake.    

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Previous studies have shown that Astragalus Gossypinus species of gum tragacanth are able to stabilize oil in water emulsion. Today, irradiation is used to disinfect many polymers. Results have shown that irradiation treatment has a significant effect on molecular weight and functional properties of Gums, especially Gum tragacanth. The aim of this study is to investigate the effect of irradiated Gum tragacanth at doses 0, 1/5, 3, 5 kGy on the emulsion stability index of oil in water emulsion which contain 0.5% w/w gum tragacanth and 10% w/w sun flower oil was studied by measuring creaming index. In order to monitor the mechanism of stabilization, rheological properties and particle size distributing parameters were measured. Rheological properties were measured by using rheometer and particle size distribution was determined using laser diffractometry. All treatments were performed three times and the data were analyzed by one way ANOVA. Significant differences between means were identified (P values < 0.05) using Duncan test. Results indicated thatrheological properties, particle size distributing and the stability of oil in water emulsion has been affected by irradiation. These changes are dependent on irradiation dose. Results show that irradiation treatment at 1.5 kGy created the most stable system by changing the studied parameters.

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In recent years, many advances have been made in improving the biocatalytic activities of enzymes. Interaction of enzymes and macromolecules have important role in stabilization of enzyme’s structure and function. Lysozyme lyses the bacterial cell wall by splitting ß (1–4) linkages between N-acetylmuramic acid and N-acetylglucosamine of the peptidoglycan in bacterial cell walls. Tragacanth is a polysaccharide obtained from exudates of the species of Astragalus. It is a very complex heterogeneous anionic polysaccharide of high molecular weight. Tragacanth consists of two main fractions: a water-insoluble component called bassorin, and a water-soluble component called tragacanthin. The aim of this investigation was to attach tragacanthin (water-soluble component of tragacanth) to lysozyme by Maillard reaction. The covalent attachment of this hydrocolloid with lysozyme was confirmed by SDS-PAGE and ion exchange chromatography. The conjugates exhibited improved solubility, foaming and emulsion properties. In addition, thermal stability of lysozyme in this conjugate was increased significantly. According to these results, attachment of lysozyme to tragacanthin can increase the application of this hydrocolloid as a functional component and lysozyme as a natural antimicrobial component in food and pharmaceutical industry.

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Electrostatic interaction between proteins and negatively charged polysaccharides leads to formation of stable colloidal system or causes complex coacervation. Therefore, in this study phase behavior of the mixtures of 0.4% milk proteins (sodium caseinate or whey protein isolate) with soluble fraction of tragacanth (up to 1%) or soluble fraction of Persian gum (up to 2%) as a function of pH (2–7) was investigated, in order to obtain appropriate protein:polysaccharide ratio to formation of soluble complexes in a wide range of pH. According to the results, the mixtures of sodium caseinate–soluble fraction of Persian gum, sodium caseinate–soluble fraction of tragacanth, whey protein isolate–soluble fraction of Persian gum and whey protein isolate–soluble fraction of tragacanth were soluble complexes at the whole pH range at the ratio of 0.4:0.6, 0.4:0.6, 0.4:2 and 0.4:1, respectively. Moreover, it was found that enhancement of total biopolymer concentration (at a same ratio) had no effect on the phase behavior of complexes. In addition, evaluation of the phase behavior of the mixture of milk proteins–alcohol-insoluble fraction of soluble part of native gums illustrated that both alcohol-insoluble and soluble fractions probably have impact on stability of complexes at mentioned ratios.

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Dahi is a traditional Indian fermented milk product that is similar to plain yogurt in appearance and consistency. As compared to yogurt, dahi has lower acidity, consequently it seems to be more effective in production of probiotic or synbiotic foods. The aim of this study was optimization of the production process and evaluation of physicochemical and microbial properties of synbiotic dahi by response surface methodology (RSM) based on Box Benken Design. Inulin (0-2.5%), tragacanth gum (0-0.06%) and storage time (1-19 days) were the factors that their impacts on the dependent variables were evaluated. In order to optimize variables, three traits including firmness, syneresis and viability of probiotic Lactobacillus acidophilus (LA₅) were considered as responses. Finally, the appropriate power and fit of model were indicated based on determination coefficient (R²), adjusted determination coefficient and coefficient of variation (CV). The determination coefficient (R²) for firmness, syneresis and microbial counting in synbiotic dahi was obtained 0.99, 0.91, and 0.98, respectively. The increase in the concentration of inulin and storage time led to improve of syneresis and firmness of the products. Also, the increase in concentration of tragacanth up to 0.03% increased firmness, while afterward up to 0.06% concentration caused negative effect and reduced firmness. The increase in concentration of tragacanth and inulin had positive effect on probiotic counting of the products, while storage time had deleterious effect on it. According to the results of optimization experiments, optimal conditions were 2.5% concentration of inulin with 0.03% concentration of tragacanth gum in 18-day holding period.

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One of the most interesting methods to develop novel rheological and textural properties in food formulation is the application of hydrocolloid blends. In this study, properties of tragacanth gum blends with qodoumeshirazi, farsi and locust bean gums were evaluated. By this purpose initially the rheological behavior of tragacanth, qodoumeshirazi, farsi and locust bean gums were evaluated individually at 0.2% total gum concentration. Further, the rheological behavior of tragacanth gum blend with the mentioned gums in ratios of 20:80, 40:60, 60:40 and 80:20 were investigated between 1.32 and 165 s^-1 shear rates. Power law and Herschel-Bulkley models were used to described their rheological behavior.These results showed that all solutions had pseudoplasticbehavior. Among the individual gum solutions,qodoumeshirazi showed by itself yield stress. The consistency coefficient of tragacanth gum was considerably higher than other gums. The apparent viscosities of blend solutions of tragacanth- locust bean gums and tragacanth-farsi gums in the ratio of 20:80 were higher than individual gums, which revealed the existence of synergism between these groups of gums. Since,farsi, qodoumeshirazi and locust bean gums are cheaper than tragacanth gum; it is possible to have cheaper formulation by using them instead oftragacanth gum.

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Ketchup is highly consumed productand hydrocolloids are used as stabilizers in its formulation. In this study, native hydrocolloids of tragacanth gum and sage seed gum were used at levels of 0.5, 0.75 and 1% in ketchup formulation. Two ketchup samples without gum and commercial ketchup were considered as controls. The physicochemical, rheological and sensory properties of the samples were evaluated. Based on the results, samples containing tragacanth gum and sage seed gum had less pH and higher brix thancontrol without gum (p<0.05). The dry matter was decreased by increasing gum concentrations of 0.75 to 1 % and syneresis of ketchup samples was also decreased by addition of native gums and increasing their concentrations (p<0.05). Samples containing higher percentages of native gums and also commercial ketchup had higher brightness (p<0.05). Indeed the color quality of most of the samples were close to the commercial ketchup. In flow measurements, all samples showed pseudoplastic behavior and the 1% of sage seed gum created a zero shear viscosity higher than commercial ketchup (p<0.05).The viscoelastic solid behavior was observed in samples in viscoelastic test and most of the samples had appropriaterheological properties. No significant difference was revealed in the sensory characteristics between samples containing native gums and commercial ketchup. (p>0.05). The results of this study showed that ketchup with proper quality can be produced by using tragacanth and sage seed gum that it can be competitive withcommercial ketchup especially at higher concentrations.

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Complex coacervation is generated through electrostatic interaction between oppositely charged biopolymers (proteins and polysaccharides). Complexation via electrostatic interactions can lead to formation of soluble or insoluble complexes. In the current research, the production and characteristics of the complexes formed from whey protein concentrate (WPC) and gum tragacanth (GT) were evaluated. In order to find the optimum pH for complexation, absorbance of protein-polysaccharide mixtures were measured at a wide range of pH (2–8), Furthermore, particle size, zeta potential, microstructure and rheological properties of the complexes were investigated. Based on the results, the best condition to form complex between WPC and GT was found to be at pH=4.5. With Increasing the amount of GT up to 0.75% w/w in a constant protein concentration (0.5% w/w), the lowest and highest particle size for WPC- GT complex was found at protein: polysaccharide ratio of 1: 1 (3018 nm) and 10:1 (4070 nm), respectively. Zeta potential changed from +3.11 mV (0% gum tragacanth) to -6.82 mV due to addition of GT (0.75% w/w). Microscopic images showed the presence of separate spherical particles, except at the concentration of 0.05% w/w. The appropriate rheological model to predict flow behavior of complexes was depended on protein-polysaccharide ratio and the dominate flow behavior index was found to be shear thinning. Increasing of TG concentration lead to lower flow behavior index as well as higher apparent viscosity, consistency coefficient and the yield stress

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Coconut is a good source of bioactive compounds due to the presence of tocopherols and phytosterols, which are increasingly used to enrich various food products. The use of coconut powder in the formulation of flavored milk with regard to its phytosterol compounds can increase the nutritional value of milk and its organoleptic acceptability among consumers. However, one of the major challenges in the flavored milk industry is their physical instability, which can be effective in using hydrocolloids at the appropriate concentration. Therefore, the aim of this study was to determine the optimal formulation of coconut milk containing tragacanthin gum (solution of tragacanth) to achieve a product with Desirable quality characteristics. For this purpose, the response surface method with the central composite investigated the effect of tragacanthin gum on 5 levels (0, 0.075, 0.15, 0.225 and 0.3%) and coconut powder on 5 levels (2, 3.5, 5, 6/5 and 8%) on the physical, chemical and sensory properties of coconut milk was used. Statistical results showed that increasing coconut powder and tragacanthin gum in coconut milk formulation significantly decreased pH and increased acidity (p<0.05). According to the results of the viscosity test, the viscosity increased as the formulation of tragacanthin and coconut powder increased (p<0.05). Results show an increase of sedimentation amount once the coconut powder increased. While by increasing the gum tragacanthin concentration, there was a twofold effect in sedimentation amount and in average level of gum, the minimum amount of sediment was observed. Also, the sensory evaluation of coconut milk samples indicated that the highest sensory acceptability was for samples containing intermediate amounts of coconut powder. But tragacanthin gum only influenced the flavor and consistency of parameters. Finally, the sample consisted of 4.28% coconut powder and 0.15% tragacanthin gum as optimum sample with desirable physical, chemical and sensory properties.
 

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Germinated mung is a rich product in proteins, vitamins, minerals, essential fatty acids, sugar, amino acids, flavonoids, sterols and organic acids. Duo to high nutritional value and limited shelf life, studying on effective solutions for increasing its shelf life is important. In the present research, effect of nonoemulsion coating of Thyme Essential oil (0-125 ppm) in tragacanth gum (0-0.2 percent) with UV-c irradiation (0-40 seconds) on physicochemical characteristics of germinated mung bean was studied. According to the statistical pattern of response surface-central composite design, we defined 20 treatments and 6 repetitions in the central point. The physicochemical characteristics of the treated samples including weight loss, PH, total phenolic, antioxidant capacity, ascorbic acid and firmness of samples were assessed after 12 days in 4 °C. The results showed an increase in total phenolic with increasing the concentration of Thyme (Zataria Multiflora ) Essential oil. Also, increasing tragacanth gum concentration increased total phenolic, and decreased ascorbic acid level and firmness. High UV-c irradiation time decreased total phenolic, antioxidant capacity, ascorbic acid levels and firmness of samples. We optimized the formulation in order to keep the highest levels of total phenolic, antioxidant capacity, ascorbic acid and firmness based on the prepared models. Optimal levels of variables were considered 104.17 ppm of the Thyme Essential oil, 0.03 percent of the tragacanth gum and 6.67 seconds of UV-c irradiation. Comparison of quality characteristics of control and optimum samples showed that the optimum sample had more phenolic compounds, antioxidant capacity and ascorbic acid than control. Furthermore, weight loss and PH of the optimum sample was lower in comparison than control.

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Encapsulation with polysaccharides is one of the new methods for increasing the stability of bioactive compounds and improving the viability of probiotics during food processing and storage. In this study, due to the high benefits of probiotic products on human health, the effect of Lactobacillus plantarum encapsulated by chitosan, tragacanth gums and their combination in a concentration of 1% (w/w) on the physicochemical and overall acceptance of pineapple juice were evaluated during 30 days storage in the refrigerator. The results showed a decrease in pH and an increase in the acidity of all samples (P<0.05). In addition, the viability of Lactobacillus plantarum was increased in the treatment encapsulated by the combination of chitosan and tragacanth gums so that, the number of viable bacterial cells was higher than 6 log cfu/ml on the 30th day of storage. The formalin index increased between the 20th and 30th days of storage in all samples (P<0.05). Also, the highest overall acceptance was belonged to the sample containing the Lactobacillus plantarum encapsulated by chitosan (P<0.05). The results showed that pineapple juice is a suitable substrate for the growth of Lactobacillus plantarum and it can be considered as a carrier for the transmission of probiotic strains to the human body. Moreover, those with special nutritional needs can take advantage of probiotic pineapple juice, including lactose and cholesterol deficiency as well as richness in mineral substances.

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This study was performed on the physical stability, rheological and sensory properties of low-fat pasteurized cream with 20% fat content in the presence of carrageenan, tragacanth and their mixtures at a constant concentration of 0.3% (w/w) and comparison with cream samples without hydrocolloids as a control. Physical stability, rheological properties, color and sensory evaluation were analyzed. Rheological parameters confirmed that all samples had a shear-thinning behavior. The results showed that the addition of hydrocolloids significantly increases the physical stability and consistency coefficient, which leads to better quality of final products. In addition, the sensory properties showed high acceptability of samples containing tragacanth. Based on the obtained results, the sample containing a mixture of 0.2% tragacanth and 0.1% carrageenan had a much greater effect on the mentioned properties, especially sensory properties, and will have a good potential for use in cream formulations.

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Encapsulation is a process to protect bioactive compounds against unfavorable environmental conditions in order to increase their stability and bioavailability. Regarding the existence of bioactive compounds in grape pomace and flaxseed oil, the aim of this research was to encapsulation of grape pomace (Vitis viniferae cv. Rash (and flaxseed oil with different ratios of maltodextrin and gum tragacanth (1:1, 1:2, 2:1) using a spray drier and evaluation of the quality properties of obtained microcapsules. The produced microcapsules were analyzed in terms of microcapsulation yield, solubility and humidity contents, total phenolic contents, antioxidant activity, the interaction between wall and core materials and microstructure. According to the results, there were no significant differences between the microcapsules in terms of humidity and solubility contents (P<0.05). The highest microencapsulation yield, total phenolic contents and antioxidant activity were observed in the microcapsules produced with equal ratios (1:1) of maltodextrin and gum tragacanth. While the spherical shape was observed by scanning electron microscope for all of microcapsule samples, the microcapsules produced with equal ratios (1:1) of maltodextrin and gum tragacanth had a more compact and homogeneous structure. FT-IR analysis also confirmed the creation of new interactions between the wall and core materials of the obtained microcapsules. The results of the present research showed that using maltodextrin and gum tragacanth as wall material in an equal ratio (1:1) had a proper performance in order to microencapsulation of grape pomace and flaxseed oil.