Showing 20 results for Naghipour
Volume 15, Issue 1 (5-2015)
Abstract
Nonlinear behavior of members and their connections during earthquake caused ductility in buildings. Also increasing the number of resisting elements of structure reduces cost of repair and reconstruction in bending structures. In contrast, the concentrically brace frames do not have sufficient ductility But their vulnerable members are limited, thus their reconstruction were much less expensive than bending frames. In order to overcome concentrically brace frames disadvantages and they providing good ductility for them, Extensive research has been conducted in the past two decades by researchers. Several methods have been proposed by various researchers which were resulted in increasing the ductility of concentrically brace frames. In this research, a new type of energy dissipation elements was introduced. This dissipation consists of a ring which increased the ductility and earthquakeenergy absorption and can be used in braced frames. Also, during an earthquake, it has depreciates significant portion of input energy by entrance to non-linear phase and forming flexural plastic hinges, so it prevent entrance of other members to non-linear phase and buckling of brace members. In order to increase the capacity of this member, a box was used that connected to the ductile ring by two plates. By increasing the diameter, rate of ductility decreased. However increasing the thickness would enhance the ductility. Stresses and deformations were been studied by using the finite element under cyclic loads. Obtained hysteresis curves indicate that the introduced element can be act as an energy absorbing member and also act as a fuse to control the buckling of brace, while providing to the required ductility. Pushover analyses for determining the seismic demand of structures and especially in earthquake engineering based on performance, it has been considered by many researchers. General basis of this method is a nonlinear mathematical model of the structure was under a lateral load pattern and this lateral load increases at a constant rate until the structure reaches a predetermined target displacement. This target displacement was measured at a control point. During the ascending increase in lateral load, resistance and stiffness of structural components were corrected at each step according to predefined nonlinear. Also performance of this ductile element was investigated in 2D concentrically brace frames under Pushover analyses. Obtained results from pushover analysis indicated that ductile element can decrease base shear force and also increase ductility of structure. The obtained results indicate that installation or replacement of steel ring in proposed connection was easily possible with low cost and high speed. Furthermore, nonlinear static analysis obtained results reflects the lower base shear force for braced frame with proposed element compared to braced frames without proposed element Which results in Cutting down construction and foundation strengthening costs of building. At the end, results of Pushover analysis of concentrically braced systems can be mentioned. High behavior coefficient of structural braced systems with proposed element represents suitable performance and ductility of proposed element in building.
Volume 16, Issue 90 (August 2019)
Abstract
In recent years, synchronous with the development and diversification of bread production, have expanded various processing methods, as well as the co processes (additives). One of the traditional products that have been welcomed by consumers for many years in eastern Asia due to the simplicity of raw materials and ease of using is roti bread. Therefore, in the present study, has been investigated the use of baking methods, such as hot-electric plates and rotary oven and compare them with the traditional method and so on is evaluated using of guar, carboxymethyl cellulose (CMC) and Carrageenan hydrocolloids (each one 0.5%) in roti bread formulation in a completely randomized double factorial arrangement test (P≤0.05). The results of this study clearly showed that application of hot-electric plates for baking along with addition of both CMC and guar gum in the formulation, had effect on the moisture content and crust L* value and in this regard the effect of CMC gum was higher than guar gum. Also, based on the results, it was found that the sample produced by the hot-electric plates containing CMC gum had the least firmness of the texture during 2 and 72 hours after baking, as well as one week after baking (P≤0.05). Finally, tasting the samples, the panelists introduced the samples produced with hot-electric plates containing CMC gum and samples produced with hot-electric plates containing guar gum as the best samples.
Volume 16, Issue 91 (September 2019)
Abstract
Nowadays, the use of pseudocereals flour in food formulations due to its high nutritional value, were increased. And also the absence of gluten protein in these food sources, the diet of patients with gluten intolerance is a good place for pseudocereals. So in this study possibility of replacing rice flour with Amaranth flour (0, 10 and 20%) and adding Mandab native gum (0, 0.25 and 0.50%) to gluten-free oily cake formulation was studied and then the quantitative and qualitative properties in a completely randomized factorial arrangement were evaluated (P≤0.05). Based on the results, it was found that by increasing the level of amaranth flour and mandab gum, the moisture content of the final product was increased. Also, the results indicated that the sample containing 20% amaranth flour and 0.5% mandab gum had the highest specific volume and porosity and lowest amount of firmness during 2 hours and one week after baking. On the other hand, the results indicated a decrease in the L* value by increasing levels of amaranth flour and also, increased the amount of L* value by adding mandab gum. Regarding to b* value it was observed that, with increasing in the level of amaranth flour, the amount of yellowness of the crust of the samples increased. Finally, the panelists introduced the samples containing 20% amaranth flour and 0.5% mandab gum as the best samples.
Volume 16, Issue 93 (November 2019)
Abstract
The tendency of people to diet to prevent weight gain and maintain health has attracted the attention of many researchers and manufacturers, and the fat has the highest caloric value in calculations, its reduction in formulation it has attracted. So in this study production of low-fat cupcake by replacement 50% of oil by 0, 10 and 20% tahinimeal, and replacing the water used in the dough cake by kombucha beverage in three levels of 0, 50 and 100% on dough characteristics and physicochemical, texture, visual and sensory properties of final product in a completely randomized design with factorial arrangement were invistigated (P≤0.05). The results showed by increasing the amount tahinimeal, viscosity and specific gravity of the batter increased and decreased respectively. Also the specific volume and porosity increased by increasing amount of tahinimeal. The results showed that the sample containing 20% of tahinimeal and replacement of 100 kombucha beverage had the least firmness during 1 and 15 days after baking. On the other hand, the results indicated that by addition tahinimeal and kombucha beverage, the crust L* and a* values were decreased and increased respectively. Finally, the panelists introduced a sample containing 20% of tahinimeal and 100% kombucha beverage as the best sample. In the next step, by comparing the characteristics of the best low fat cake by the control sample (without additive and without oil substitution) increased protein content, decreased fat content and decreased peroxide levels were observed. Therefore, due to the positive results of this study, can be produced the low-fat cupcake that enriched by tahinimeal and kombucha beverage which has desirable qualitative and quantitative properties and reducing health hazards caused by using shortening.
Volume 16, Issue 94 (December 2019)
Abstract
The use of sourdough in bread formulation affects the physicochemical properties of the final product leading to enhancement of the nutritional value and reduction of waste. Therefore, in this research, flours obtained from two different varieties of wheat including Mehregan as a hard and strong variety with high protein content and Sardari as a soft and weaker wheat with lower protein content, both with different extraction rates (whole flour, 88 and 77%) were used to prepare sourdough. After preparing the baguette sample, the physicochemical and sensory properties of the products were evaluated using a completely randomized factorial design (P≤0.05). The results indicated that higher amounts of organic acids, i.e. lactic acid and acetic acid were produced in the sourdoughs obtained from Mehregan compared to those made from Sardari which in turn led to their higher acidity and lower pH. Moreover, the breads made from Mehregan flour possessed higher moisture content, greater specific volume and porosity and lower hardness than the samples produced from Sardari variety. The increase in extraction rate for both flour types affected the aforementioned attributes the same way as did increase in protein content. The findings showed that increase in protein content (Mehregan vs. Sardari) and/or extraction rate of the flour enhanced the color parameters of L* and a* but the b* was not significantly influenced by either factors. Having softer and more porous texture, more desirable appearance and more delicious flavor, the sample made from Mehregan flour received higher total sensory scores than Sardari samples. Likewise, the increase in extraction rates for both flour varieties were accompanied by higher sensory acceptability. Hence, the baguette bread obtained from Mehregam with 100% extraction rate was introduced as the best sample.
Volume 17, Issue 106 (December 2020)
Abstract
Resistant starch type III as a dietary fiber is included in the prebiotic composition. It can be used to enrich low-calorie, gluten-free diets for celiac patients. The aim of this study was to investigate the possibility of improving the quantitative and qualitative properties of gluten free rice cake via replacement rice flour by resistant starch type III at levels of 0, 5, 10, 15, 20, 25 and 30%. Physicochemical, textural and sensory properties of the product were evaluated in a completely randomized design (P˂0.05). The results showed that replacing the rice flour by resistant starch in the gluten free rice cake formulation reduced the specific gravity of batter and increased the moisture content of the final product. Also, by replacing rice flour by resistant starch up to 20%, the height, specific volume and porosity of the final product increased and then decreased. On the other hand, the sample containing 20% resistant starch had the lowest firmness at 2h, 3 and 7 days after production. In addition, the results showed that 25 and 30% replacements of the resistant starch in gluten-free rice cake formulation by rice flour, the L* value of the crust and crumb increased and the a* and b* were reduced. Finally, the panelists by evaluating the sensory properties such as shape, color, texture firmness and softness, taste and overall acceptance the sample containing 80% rice flour and 20% resistant starch type III introduced as the best sample. Therefore, according to the results of the physicochemical and sensory evaluation, replacement of 20% rice flour by resistant starch type III in gluten free cake formulation can produce a lower calorie product suitable for celiac patient.
Volume 18, Issue 5 (9-2018)
Abstract
Abstract In addition to the operational and environmental loads, an offshore pipeline may be subjected to accidental transverse loads by falling heavy objects or trawl gears. As a result, the load bearing capacity of the pipeline may be significantly impared by the dents, gouges or other types of damages caused by the impact. Such damage to an offshore structure may have serious environmental and economic consequences. In this study, results of experimental investigations on the residual strength of plain and gouged dented steel pressurized pipes under monotonic axial compression are presented. Some series small-scale specimens were fabricated from API-5L-X80 steel pipes with (D/t) ratio of 22 for the purpose of experimental tests. The specimens were dented by a spherical indenter with (d/D) ratio of 0.45 and gouges were applied along the pipe axis on the outer surface of the middle portion, whose cross section was rectangular. Defected and intact specimens were then collapsed by monotonic axial compression loading whilst subjected to constant internal pressure. In this research, effects of some key non-dimensional parameters such as dent depth, presence of the internal pressure and geometrical parameters of gouges have been studied.
Volume 18, Issue 113 (july 2021)
Abstract
Now a day antioxidants are widely used in foods to reduce the rate of oil oxidation reaction and researchers looking for potent antioxidants by less toxicity and greater efficacy. Plants are one of the best sources of natural antioxidants. Therefore, the aim of this study was to investigated the effect of adding different levels of alcoholic extract of Salvia leriifolia (0, 1, 2 and 3%) as a natural preservative to improvement storage time of fermented doughnut compared to TBHQ as commercial antioxidant on the physicochemical, textural and sensory properties of the final product in a completely randomized design (P˂0.05). The results showed that increasing the level of Salvia leriifolia extract from 0 to 3% had no effect on moisture content, specific volume, porosity and firmness of the final product (evaluated in three times of 2 h, 4 and 7 days after baking). However, by increasing the amount of this extract in fermented doughnut formulation, the peroxide index compared to other sample and the amount of total phenolic content, the antioxidant activity by DPPH method and the oxidative stability index at 2h, 4 and 7 days after baking were decreased and increased, respectively. On the other hand, the results showed that addition of Salvia leriifolia extract at different levels had no effect on the sensory properties of the final product. The results also indicated that the antioxidant activity of the sample containing 3% of Salvia leriifolia extract had the ability to compete with fried doughnut in oil containing synthetic antioxidant TBHQ. Therefore, the sample containing 3% of Salvia leriifolia extract was selected as the best sample because it had high antioxidant resistance, secondly, the addition of this extract had no adverse effect on physicochemical and sensory properties of the final product.
Volume 18, Issue 114 (August 2021)
Abstract
One of the practical and inexpensive solutions in improving the characteristics of the bakery and reducing the waste of this category of products is to use sourdough. Therefore, in this study, the possiblity to use kombucha beverage and soybean milk as a water substitute in sourdough formulations prepared from Lactobacillus fermentum and Lactobacillus plantarum separately and to evaluate the physicochemical and sensory properties of toast samples prepared from this Sourdoughs were examined. The results showed that by adding sourdough prepared from kombucha beverage and soybean milk, the moisture content and acidity of the final product increased and the pH decreased. On the other hand, Lactobacillus fermentum was more effective than Lactobacillus plantarum in reducing pH and increasing acidity. In addition, after examining the amount of lactic acid and acetic acid in the product, it was found that the amount of lactic acid in samples prepared from sourdough containing kombucha beverage and kombucha beverage was maximum while the amount of more acetic acid in samples prepared from sourdough containing kombucha beverage and Lactobacillus fermentum was higher. Samples containing kombucha beverage had the lowest amount of firmness and the highest amount of specific volume and porosity, and the type of primer used in the sourdough had no effect on the amount of these parameters. On the other hand, the study of the crust color values showed that by adding kombucha beverage and soybean milk in sourdough formulation, the amount of L* and a* values was decreased and increased respectively. Finally, sensory evaluators gave the highest score to two samples of sourdough containing kombucha beverage in the presence of both Lactobacillus plantarum and Lactobacillus fermentum. Therefore, these compounds can be used to produce sourdough with better performance properties.
Volume 18, Issue 115 (September 2021)
Abstract
Improving the quality of bread and bakery products by modifying the formulation and production process is one of the most important ways to increase the level of public health in society. In this regard, steamed bread is free of harmful compounds such as acrylamides due to different baking processes, including foods. Therefore, the aim of this study was to investigate the effect of adding glycerol at levels of 0, 0.5 and 1% and using one-stage and two-stage fermentation methods on physicochemical and sensory properties of composite steamed bread (wheat-rye) in a completely randomized design with factorial arrangement in order to produce suitable bread taste for the Iranian consumer and improve the shelf life of the final product. Based on the results, it was found that by increasing the glycerol and using the two-stage fermentation method, the moisture content of the final product and firmness (during 2 and 72 hours after baking) increased and decreased respectively. In addition, the use of two-stage fermentation method improved the porosity and specific volume of the final product. However, glycerol had no effect on these parameters of bread. On the other hand, the amount of L* value increased with increasing glycerol and using two-stage fermentation method, while the amount of a* and b* values remained constant. In the sensory evaluation section, the taste judges gave the highest score to the sample containing 11% glycerol and prepared by two-stage fermentation process. Therefore, by localizing the technical knowledge of producing steamed bread, bread with better nutritional value can be contracted in peoplechr('39')s food basket.
Volume 18, Issue 117 (November 2021)
Abstract
Today, preventing the loss of by-products of food industry and their optimal use in order to increase the quality of food has attracted the attention of many researchers. So the aim of this study was to improve the quantitative and qualitative characteristics of gluten-free fermented doughnut based on rice flour by adding corn gluten meal and tahini meal on three levels of 0, 5 and 10%. The results showed by increasing the amount of corn gluten meal and tahini meal, the amount of protein and peroxide of the final product increased and decreased respectively. Also, The results showed that only increasing the amount of tahini meal in the formulation increased the moisture content, specific volume and porosity and decreased the firmness of the tissue, while the addition of corn gluten meal had no significant effect on these parameters. On the other hand, only increasing the amount of corn gluten meal in the formulation reduced the fat content of the final product and adding tahini meal did not cause a significant change in this regard. The results also showed that with increasing the amount of corn gluten meal and tahini meal, the amount of L* and a* crust values decreased and increased, respectively and the addition of corn gluten meal increased the amount of b* crust value. Finally, introduced two samples containing 5% corn gluten meal and 10% tahini meal and the sample containing 10% tahini meal and without corn gluten meal as the best sample. So, it can be concluded that the use of these meal in addition to the development of industries and economic productivity, improves the quantitative and qualitative characteristics and enhances the nutritional value of the final product.
Volume 19, Issue 2 (7-2019)
Abstract
Concrete -filled steel tube are widely used today in many civil engineering structures. The advantage of steel members is their high tensile strength and ductility and, on the other hand, concrete members have high compressive strength. Composite members combine steel and concrete, which have positive properties of both materials. In members under compressive loading, circular tube columns, for a given cross section area, have the large uniform bending strength in all directions in comparison to other cross-sections. Filling the pipe with concrete will increase the ultimate strength of the member without significantly increasing costs. On the other hand, the concrete in the tube delays the local buckling of the pipe wall. In this type of section, the outward buckling will reduce the amount of confinement, ductility and ultimate strength.
Subsea and offshore marine structures are mainly made of hollow steel circular sections, where water pressure reduces their load carrying capacity. By converting these sections to concrete filled tube, external pressure can improve the behavior by increasing the confinement. This paper tries to investigate the effect of external pressure on the ultimate strength of CFT, so that the use of this kind of composite sections in construction and retrofitting of marine structures would be investigated. This paper tried to evaluate the effect of lateral pressure on improving the behavior of concrete-filled steel tubes (CFT) by conducting laboratory studies. For this purpose, tri-axial testing set up, with capability of 400 bars pressure, was designed and constructed by the authors. Parameters such as lateral pressure, concrete strength and diameter to thickness ratio (D/t) of steel tube were tested.
Concrete with strength of 15 to 45 MPa was cast in pipes of 0.5 to 2 mm thickness and subjected to axial loading under external pressure between 0 and 150 bars. All specimens have a constant diameter of 100 mm and a height of 250 mm and are filled with ordinary concrete. All specimens have a diameter of 100 mm and a height of 250 mm and are filled with normal concrete. To evaluate effect of lateral pressure on the final strength, the ratio of d Parameters such as ultimate strength and failure mode of specimens along with their displacement load diagrams were investigated. Diameter to thickness in some samples was considered higher than the values proposed in the standards. Experimental tests results were compared with the relationships presented in the Eurocode 4 and AISC standards.
According to the calculations, the AISC standard result in conservative numbers compared to the EC4 standard for the ultimate strength of the specimen. External pressure has increased the loading capacity, as well as the ductility of the specimens by preventing the buckling and sudden crushing of the core concrete. Increase in load carrying capacity due to external pressure was up to 91% in some specimen. The effect of increasing on ultimate strength on the lower thickness specimens was significant. In conclusion, results of the experiments showed a significant effect of lateral pressure on the final strength of the CFT with normal concrete.
Volume 19, Issue 128 (October 2022)
Abstract
Today, increasing the quality and nutritional value of food consumed by patients with celiac disease has attracted the attention of many researchers. Therefore, the aim of this study was to investigate the possibility of improving the quantitative and qualitative characteristics of gluten-free cake by replacing brown rice flour at three levels of 0, 50 and 100% with white rice flour in the presence of native Iranian gums (Isfarzeh, Qodoume Shirazi and Farsi separately at level of 1%). Results showed by increasing the amount of replacement of brown rice flour and adding gums, the viscosity of the dough increased, while with increasing the amount of these compounds, the specific gravity of the dough increased and decreased, respectively. The results showed the amount of protein, fat, moisture, firmness of the texture (during both periods) increased with the replacement of brown rice flour, while the addition of gums only affected the moisture and firmness of the texture in such a way that with the addition of gums, the amount of texture firmness decreased and the amount of moisture in the product increased. Regarding the specific volume and porosity of gluten-free cake, the results showed that with increasing the replacement of brown rice flour and the use of gums, the amount of these parameters decreased and increased, respectively. According to the results, with increasing the amount of replacement of brown rice flour, the amount of L* and a* components of the samples had a downward and upward trend, respectively, while the addition of gums only increased the amount of L* component. Finally, the panelists evaluated the sensory properties and introduced two samples containing 0% brown rice flour with Isfarzeh gum and sample containing 50% brown rice flour and Isfarzeh gum as the best samples.
Volume 19, Issue 131 (January 2022)
Abstract
The use of quinoa seeds and its derivatives in the bakery products formulation, in addition to improving the nutritional value of the final product, reduces dependence on plant sources with high water requirements such as wheat and rice, so in this study the effect of rice flour replacement by whole quinoa enzymatic malt at levels of 0, 2.5, 5, 7.5 and 10% on physicochemical and textural properties and internal structure of gluten-free bread was investigated. The results showed that by increasing the amount of quinoa malt (up to 10%) in the product formulation no significant effect on moisture content and water activity was observed. However, the firmness of the texture in 2 and 72h after baking increased by 10% of quinoa malt. Also, the specific volume and porosity of the product was reduced only at level of 10% of quinoa malt flour. On the other hand, by increasing the amount of quinoa malt flour, the enthalpy of the samples decreased (2 and 72h after baking), while the enthalpy increased with increasing product storage time. The results of crust color evaluation showed a decrease in the amount of L* value and an increase in the amount of a* and b* values by increasing the amount of malt flour in the formulation, which indicates more turbidity of the product. The results of images obtained by Scanning Electron Microscope showed the average values of diameter and pore area of the product decreased by addition quinoa malt. Finally, the panellists gave the highest overall acceptance score to three samples containing 0, 2.5 and 5% of quinoa malt, which indicates the improvement of quantitative and qualitative properties of the final product using enzymatic derivatives and gluten-free quinoa.
Volume 20, Issue 4 (11-2020)
Abstract
Concrete-encased concrete-filled steel tube (CFST) has been presented to integrate reinforced concrete (RC) and CFSTs that have been used increasingly in high-rise buildings and bridges in the world. Concrete-encased CFST exhibits higher confinement of the concrete core, high stiffness and strength, better durability and ductility, small sectional size, higher fire resistance due to the protection of the outer RC encasement compared to CFST, avoidance of local buckling and corrosion of steel tube, and easier connection with steel RC beams. On account of the insufficient research and the unknown behavior of these beam types, in this research, prestressed concrete-encased CFST (PCE-CFST) beams that incorporate CFST in the compression zone to improve the strength of concrete, and prestressed strands in the tension zone to control cracks in reinforced concrete (RC) beams are numerically investigated. The objective of this study is the finite element analysis of parameters that are not feasible to be examined through experimental specimens. Hence, the experimental study has been done to validate the nonlinear finite element modeling and a full-scale model is constructed to explore the flexural behavior of the cross-section. The model is then developed to include parameters such as the longitudinal rebar ratio, prestressed strand ratio, core concrete ratio, and the steel tube ratio indices. Based on findings, a good agreement was observed in the moment-deflection diagrams and the failure modes between the experimental and numerical results. Then the model was developed and 9 PCE-CFST beams is modeled by finite element software of ABAQUS to investigation of longitudinal rebar ratio (0.0257, 0.00856, 0.00286), prestressed strand ratio (0.00228, 0.00912, 0.000569), core concrete ratio (0.0206, 0.07799, 0.0281), and the steel tube ratio (0.01385, 0.00615, 0.000385) indices. The beam specimens were subjected to four-point loading and the parameters of bearing capacity, moment-deflection curve, energy absorption, ductility, failure mode, bending stiffness were investigated. Examination of indices revealed that as the prestressed strand ratio increases, displacement ductility, flexural stiffness and ultimate moment increase by 1.47, 1.06 and 3.22 times, respectively. Further, the elastic and entire absorbed energy of cross-section escalate by 1.04 and 3.22 times respectively, with increasing prestressed strand ratio. Likewise, by increasing the index of longitudinal rebar ratio, flexural stiffness and ultimate moment are 1.18 and 1.22 folded, respectively. In addition, the elastic absorbed energy is increased by 2.85 times as the longitudinal rebar ratio increased. As the ratios of core concrete and steel tube increase, the flexural stiffness is reduced by 5% and 6%, respectively. While, by increasing the core concrete and steel tube ratios, the ultimate moment grow by 1.05 and 1.29 times, respectively. The only effective index on the cross-section ductility and the entire absorbed energy is the prestressed strand ratio. The longitudinal rebar ratio has also the greatest increasing impact on the flexural stiffness and the elastic absorbed energy. Moreover, the core concrete ratio has the least effect (less than 10%) on the flexural stiffness. The prestressed strand and core concrete indices have respectively the highest and lowest escalating effects on the ultimate moment. As a consequence, an increase in the prestressed strand and longitudinal rebar ratios lead to a rise in the flexural stiffness and ultimate moment. On the contrary, an increase in the steel tube and core concrete ratios, decrease the flexural stiffness and gives a marginal increase to the ultimate moment. It was also unveiled that the failure mode of full-scale beams is flexural, and shear crack and shear capacity govern the behavior of PCE-CFST beams with shear span-to-depth ratios of less than 2. As shear span-to-depth ratio increases, that is, the shear failure mode shifts to flexural, flexural stiffness decreases, yet the ultimate bending moment increases. Additionally, a strut-and-tie model was proposed to describe the load transfer mechanism of PCE-CFST beams.
Volume 20, Issue 138 (August 2023)
Abstract
Resistant starches are classified in the category of indigestible starches and are introduced as a prebiotic product, which has lower calories and is cheaper compared to other dietary fibers. Therefore, the purpose of this research is to use type III resistant starch produced by thermal method at levels of 0, 5, 10, 15, 20, 25 and 30% in a completely random design as a substitute for wheat flour in biscuit, doughnut and cookie formulation. The results showed that by replacing wheat flour with resistant starch in the formulation more than 20%, the moisture content and water activity of the final product increased and decreased respectively. The specific volume and porosity of the doughnut were stable up to the level of 15% of resistant starch and then decreased. Also, the sample containing 15% resistant starch had the lowest amount of firmness in all the products. On the other hand, with the replacement of resistant starch in the formulation of the examined products on levels of 15% and above, the amount of L* value increased and the a* and b* values were decreased. The panelists also introduced the sample containing 15% resistant starch as the best sample. Therefore, it can be said that by replacing 15% of wheat flour with resistant starch, in addition to maintaining the physicochemical, textural and sensory characteristics of the final product, it is possible to enrich these snacks and the consumer can benefit from the benefits of using prebiotic products.
Volume 20, Issue 141 (November 2023)
Abstract
Food security is always under threat due to the limited production resources in agriculture and dependence on a single product such as wheat. Sustainable agriculture requires that in the production of agricultural products, one-sided and single products should not be used. So the aim of this study was replacement of 10% of the wheat flour in the semi-volume Barbari bread formulation by the whole meal flour and malt flour of barley, oats, quinoa and amaranth. The results showed the sample containing 10% whole oat flour had the highest amount of moisture, specific volume and porosity. While the use of malt decreased the amount of the mentioned parameters. Regarding the evaluation of the firmness of the texture, the results showed that the sample containing whole oat had the lowest firmness in 2 h and 3 days after baking, and it should be mentioned that the use of the malt of the studied grains compared to the grain increased the firmness. Also, the analysis of the results showed that the amount of protein in the samples containing oat, amaranth and quinoa flour was higher than other samples. Examining the crust color of the product, showed a decrease in the amount of the L* value and an increase in the amount of the a* value with the addition of malt flour. During the sensory evaluation, the panelists assigned the highest overall acceptance score to the sample containing 10% whole oat flour. Therefore, the producers can enrich their products with oat flour without reducing the quality.
Volume 21, Issue 154 (December 2024)
Abstract
Breads Produced by sourdough have a lighter texture and a higher quality of chewing. Due to the fact that sourdough prepared from wheat or rye flour cannot be used in the formulation of gluten-free products. Therefore, in the present study, millet, amaranth and quinoa flours and Lactobacillus fermentum and Lactobacillus plantarum starters were used individually and in combination in the sourdough formulation. Produced gluten-free sourdoughs were added to gluten-free bread dough in level of 10% and quantitative and qualitative characteristics of the produced bread samples were evaluated in a completely randomized design with factorial arrangement (P≥0.05). The results of evaluating the moisture content of the produced breads showed that two samples prepared from sourdough containing mixed starter and quinoa flour and the sample prepared from sourdough containing Lactobacillus plantarum starter and millet flour had the highest and lowest moisture content, respectively. Also, the samples containing sourdough prepared from quinoa flour had the highest amount of pH, acidity and organic acids. In the evaluation section of porosity and specific volume of the product, it was determined that the samples prepared from sourdough containing Lactobacillus fermentum starter and quinoa flour had the highest porosity and specific volume. Also, the texture evaluation results showed that the samples prepared from sourdough containing mixed starter and quinoa flour had the lowest hardness. On the other hand, the examination of the crust color values showed that the amount of L* and b* values increased by using sourdough prepared from quinoa flour in the gluten-free bread formulation. While the type of starter used had no significant effect on these values. At the end, by sensory evaluation, assigned the highest overall acceptance score to the sample prepared from sourdough containing mixed starter and quinoa flour.
Volume 22, Issue 3 (5-2022)
Abstract
In this paper, a finite element analysis of the behavior of embedded CFST columns to the foundation under axial-lateral combined loading. First, the proposed finite element model is compared and analyzed by the experimental results of previous research, which showed that the local damage, failure patterns and hysteresis curves were consistent. A detailed parametric study to evaluate the cyclic behavior of embedded CFST columns to the foundation with the characteristics, the ration diameter to thickness, embedded length, compressive strength and connection conditions CFST column to the foundation. Based on the parametric study, the values of stiffness, strength, ductility and energy for the studied specimen have been calculated. The results showed that using the proposed finite element model, weak cyclic behavior for CFST connection to the foundation in the conditions of connection with the base plate and better cyclic behavior for the CFST column and its connection to the foundation in the embedded conditions is obtained. In addition, the hysteresis behavior of the CFST column connection with the embedded stiffener plate is much better than the embedded connection without the stiffener. The rings stiffener of the hysteresis diagram changes compact condition with increasing concrete strength. In addition, lateral strength, lateral stiffness, ductility performance and cumulative energy dissipation also increased in compact specimens with increasing confine concrete. The failure modes of the CFST connection to the foundation with the base plate are the same as the embedded connection mode without the stiffener and with the ring stiffener. The failure modes in these three modes are from the connection as a tearing steel pipe at the end of the column. In the case of an embedded connection with a longitudinal stiffener, it is a diagonal crack of the concrete on the foundation. Lateral strength, lateral stiffness, ductility performance, and cumulative energy also increase with increasing steel pipe thickness. CFST column burial conditions with hardeners have a positive effect on the hysteresis rings of CFST connection to the foundation, and this type of connection has been able to significantly improve lateral strength, lateral stiffness, ductility and dissipative cumulative dissipation energy.
Volume 23, Issue 5 (May 2023)
Abstract
Fused deposition modeling (FDM) is one of the most common 3D printings technologies. Low cost and the ability to produce models using wide range of thermoplastic polymers, makes this process suitable for rapid prototyping and manufacturing some commercial parts. The manufacturing complicated parts and increasing their qualities are possible, using more than three degrees of freedom printers. In this paper, a 5-DOF 3D printer is introduced. The mechanism of this printer is 4-DOF parallel mechanism with one additional degree of freedom resulting from rotation of printer bed about Z-axis. In order to generate tool path for 5-DOF printer, a CAM software was developed with python. For controlling the printer, control software was designed based on open-source Repetier framework. Since original framework only supports 3-axis printers, source code needed to be changed such as extending source code to support 5-axis and adding mechanism inverse kinematics. By using this 5-Dof mechanism, the prints of complicated parts without using the support are possible.