Food Engineering
Javad Safari; Jafar Hashemi; Azadeh Ranjbar Nedamani
Abstract
Introduction Due to the importance of product appearance quality in product grading and the impact of factors such as area, uniformity, and various defects on the product quality, and also, the ability to recognize these features at a very low cost, image processing techniques, is one of the methods ...
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Introduction Due to the importance of product appearance quality in product grading and the impact of factors such as area, uniformity, and various defects on the product quality, and also, the ability to recognize these features at a very low cost, image processing techniques, is one of the methods used to evaluate food quality. Therefore, in this study, a non-destructive image processing method was used to investigate the factors affecting the color and shrinkage of apple slices during drying. Materials and Methods Golden delicious apples were used in this research. The central part of the apple (including the rivet, seeds, and tail) was removed by a kernel separator and sliced into 3, 5, and 7mm thickness and approximately 7 mm diameter slices using a hand slicer without separating the skin. Three temperatures of 60, 70, and 80 °C were used to dry the samples. To determine the moisture content of a sliced apple, the samples were first weighed on a digital scale, then placed in a dryer, and the experiment was continued until the samples reached equilibrium mass. Due to the high importance of moisture ratio in controlling the drying process, moisture rate (MR) and moisture content (MC) were calculated, and samples were taken to investigate the amount of surface shrinkage, general color changes and browning index. After extracting L*, a*, and b* values, total color changes and browning index (to show the intensity of brown color in the product) for all samples before and after drying were calculated and evaluated to describe color changes after drying. Results and Discussion The drying kinetics results showed that the drying process significantly depends on the thickness of the samples. According to drying curves, at the early stages of drying, the decrease in humidity occurs more severely and the graph has a steeper slope, but as the process continues and the moisture content of the product decreases, the slope of the curve decreases. In the early stages of drying, due to the presence of water inside the fresh fruit cells, there is a pressure balance between the fruit and the surrounding environment, which causes the fruit to remain swollen. However, as the drying time progressed, contractile stresses are created, which cause superficial shrinkage. In this study, it was observed that increasing the thickness from 3mm to 7mm, reduced the final shrinkage on the surface of apple slices by 11% at 60 °C, 12% at 70 °C, and 13% at 80 °C. After moisture leaves the surface of the product and heat penetrates into the product, moisture begins to leave the product by conducting interstitial convection. When moisture moves to the surface, the mechanical balance and consequently the textural structure of the sample is disturbed due to the creation of different spaces in thickness. According to the results, increasing drying time and thus decreasing the moisture content, increases the percentage of apple shrinkage. On the other hand, at a certain thickness, with increasing temperature, the percentage of shrinkage changes in the thickness of the product decreases. Therefore, at thicknesses of 3, 5, and 7 mm, the increase in temperature from 60°C to 80°C, decreased the amount of shrinkage thickness by 16, 12, and 8%, respectively. It is in higher thicknesses that react with heat and change the color of the fruit due to the Maillard reaction. After complete drying of apple samples, the highest amount of color change was related to the thickness of 7 mm and a temperature of 80°C, which was equal to 1.254. Also, the lowest rate of discoloration of apple slices in a thickness of 3 mm and a temperature of 60 °C was 0.889. The browning index (Bi) in the high thickness of apple slices is less affected by the process temperature due to the increase in moisture level. For this reason, the rate of browning was very low among the experimental samples and the highest rate of browning was related to the thickness of 7 mm and the temperature of 80 °C was 585/2559. Also, the lowest rate of browning of apple slices was observed in the thickness of 3 mm and the temperature of 60 °C was 584.254. Conclusion Finally, it was found that the thickness and temperature factors can have an effect on the quality of product during drying process. The results of this study can provide a cheap and fast way to control the quality of fruits during drying and help producers of these products select the main process factors that affect the final quality.
Food Technology
Azadeh Ranjbar Nedamani
Abstract
In recent years, cold plasma is one of the expected alternatives for post-harvest treatments and post-harvest management of products. A surface discharge plasma system was used for investigating the destruction time of Bacillus cereus, Bacillus coagulans, Bacillus stearothermophilus, and Clostridium ...
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In recent years, cold plasma is one of the expected alternatives for post-harvest treatments and post-harvest management of products. A surface discharge plasma system was used for investigating the destruction time of Bacillus cereus, Bacillus coagulans, Bacillus stearothermophilus, and Clostridium botulinum in bottled milk. The simulation was performed by COMSOL a3.5 software for a two-dimensional geometry. The collected experimental data were simulated in COMSOL software. The k factor of microorganism deactivation data was used to validate the simulated data. Results showed that the production of reactive oxygen species during plasma treatment increases with time and extends to the entire container. The concentration of reactive oxygen species (at the output of the plasma probe) at the beginning of the production was high, and at the end when they leave the free surface of the milk, the concentration decreased. Increasing the initial temperature of milk sample, from 50 to 80℃, can cause significant changes in the amount of ozone from 125 mol/m3 to 266 mol/m3, respectively (p <0.05). However, voltage changes in these two temperatures did not show a significant effect on ozone concentration. Also, immediately upon the initiation of plasma treatment, plasma destruction begins where the concentration of active species is higher. It is shown that among the four studied bacteria, Bacillus stearothermophilus has the highest resistance against cold plasma, and after that other bacteria have shown similar resistance. Finally, it can be concluded that the deep plasma treatment in bottle can make it possible to overcome the surface limitation of cold plasma treatment.
Food Technology
Azadeh Ranjbar Nedamani
Abstract
In recent years, there has been an increasing interest in the application of plasma technology in food preservation technologies. Plasma is nonthermal physical processing that has a high potential in the field of food processing. In this study, a mathematical model was investigated for yeast deactivation ...
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In recent years, there has been an increasing interest in the application of plasma technology in food preservation technologies. Plasma is nonthermal physical processing that has a high potential in the field of food processing. In this study, a mathematical model was investigated for yeast deactivation during plasma treatment. The definitive screen design was used to investigate the factors that affect yeast deactivation by plasma. Four factors of voltage (A: 20- 30 kV), Vessel diameter (B: 40- 60 mm), process temperature (C: 20- 40ºC), and type of plasma media (air or water) were selected. Then the treatment was simulated by COMSOL software. The responses of reaction kinetics coefficient, the ozone concentration, and final deactivation time were analyzed by definitive screen design expert to find the effective model parameters and process optimization. The results show that plasma treatment in water can have the strongest effect than air plasma. The changes in the number of microorganisms have a linear relationship with process time at different voltage- temperature conditions, but the ozone concentration dramatically changes at different combinations of voltage and temperature. The analyzed data show the kreac is affected significantly by the diameter of the vessel and the 221 types of process media (water or air). The ozone concentration only depends on the type of plasma media and the final 223 process time significantly depends on vessel diameter and type of media. Also, in plasma treatment, media type had a significant effect on all 3 responses, while the effect of temperature was only on final process time. For example, at temperature 20ºC the ozone concentration decreased at the first time of treatment and then stay constant, but at 30ºC, the ozone production increased with treatment time. This study showed when an RSM design was applied for designing the experiment which considers different process factors, the results can significantly differ from the study on only one-factor. In plasma treatment, media type had a significant effect on all 3 responses, while the temperature shows its effect only on final process time. Thus it can be concluded that with proper selecting of plasma media, this technology can be used for deactivation of food microorganisms
Food Technology
Azadeh Ranjbar Nedamani
Abstract
The application of natural ingredients in food formulations plays a key role in public health. The application of natural colorants is helpful in human health. Most of the natural colorants have additional roles such as antioxidant or antimicrobial activities. Natural colorants in foods especially in ...
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The application of natural ingredients in food formulations plays a key role in public health. The application of natural colorants is helpful in human health. Most of the natural colorants have additional roles such as antioxidant or antimicrobial activities. Natural colorants in foods especially in cake formulation, make an attractive view for Childs. In this study, the effects of three natural colorants of lycopene, chlorophyll, and Berberis Vulgaris extracts were investigated in cupcakes. The amounts of 0, 0.5, 1.5, and 2% of extracts were used. The moisture, volume increment, porosity, color parameters, total phenols, antioxidative effects of extracts, and sensory properties were evaluated. Results showed that all-natural colorants increase the final volume, porosity, oxidative stability, phenol content. Also, they reduced the moisture and lipid oxidation of samples. The red, green, and blue parameters of cakes decreased, especially in samples with Berberis Vulgaris extract. The lightness of all samples was significantly reduced after cooking but the lightness of samples with 2% lycopene oleoresin was not high. .Sensory evaluation showed that the color, flavor, and odor of cakes prepared with lycopene, and chlorophyll oleoresin had the highest scores. The cakes prepared with Berberis Vulgaris extract had the lowest scores in color, flavor, and odor, but the texture and porosity were the same as other samples. Finally, it can be concluded that lycopene oleoresin showed significant acceptance, antioxidant effect, and acceptable physical properties. Results can be helpful for researchers and food industries because the lycopene oleoresin showed a significant antioxidant activity after 3 weeks and the total phenols of Berberis Voulgaris extract showed significant stability after 3 weeks. Especially, the panelists have a significant reflection of the colored food. They propose them as an attractive materials for consumption.
Azadeh Ranjbar Nedamani
Abstract
Amount of heat transfer temperature was stimulated in the slowest heating zone of 3.5% starch dispersion during canning sterilization with 10% headspace. The computational fluid dynamics software COMSOL 4.1 was used and governing equations for energy, momentum, and continuity were computed using a finite ...
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Amount of heat transfer temperature was stimulated in the slowest heating zone of 3.5% starch dispersion during canning sterilization with 10% headspace. The computational fluid dynamics software COMSOL 4.1 was used and governing equations for energy, momentum, and continuity were computed using a finite volume method. The effect of container geometry (cylinders with 6*10cm and 10*6cm dimensions, and cones with 10 cm height and 5 cm radius on 0 and 180° position) on heat penetration parameter (j) and microbial lethality (L) in slowest heating point were investigated. The temperature of the slowest heating zone was monitored by a thermocouple and then compared with the predicted temperature by software. It was determined that cone-shaped container had the fastest heat transfer during sterilization. Also, container geometry has a significant effect on slowest heating zone shape, position, final temperature, j, L, and F-value.
Azadeh Ranjbar Nedamani; Aman Mohammad Ziaiifar; Mahdi Parvini; Mahdi Kashani-Nejad; Yahya Maghsoudlou
Abstract
Introduction: Canning is the most effective way to food preservation. Starch- based foods include the major food materials such as porridges. These foods due to sensitivity to high shear rates used in rotary retorts and thus texture decomposition, usually sterilized in static retorts. Broken heating ...
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Introduction: Canning is the most effective way to food preservation. Starch- based foods include the major food materials such as porridges. These foods due to sensitivity to high shear rates used in rotary retorts and thus texture decomposition, usually sterilized in static retorts. Broken heating behavior, can headspace and initial temperature have important role on heat transfer rate and the position of cold area in these products. Heat breaking phenomena in the thermal curve, which can be seen in foods containing starch, is essentially related to gelatinization and destroying of starchgelstructure. Starchmaybe naturally exist in foods ormay be added to food formulations as an additive to create the consistency, filler, volumeproviders, emulsionstabilizer and etc. However, during thermal processing of foodscontaining high amounts of starch, complexstructural changes occur which leads to viscosity increases. These changes aredue to structural changes of starch during gelatinization; such as irreversible swelling of the starch granules, melting of starchcrystals, leaking of starch granule compound. Depending on thetype of starch and its concentration, the final product can bean aqueous solution or agel structure. Increasing in starch viscosity after gelatinization leads to decrease in heating rate, but with the advancement of heating time, when most granule swelling occurs, and the granules are being disrupted and the viscosity is reduced. This leads to increase the heating rate. This dual behavior of starch dispersion viscosity, leads to break in heating curve. Such solutions are named broken heating curve foods.The aim of this study was numerical simulation of the effect of starch concentration and initial temperature on heat transfer rate of starch dispersion during static sterilization with COMSOL software. Materials and methods:To prepare 100ml of 3.5 and 5% starch dispersion, 3.5 and 5 g starch was dissolved in 96.5 and 95 ml distilled water at 24.7C, respectively. The solution was then heated at 50C for 10 min to avoid sedimentation during the heat process. Samples were filled at 50 and 75C initial temperatures. In each can (9.9×10.1cm), T- type thermocouple was placedin one-third length from the bottom. All measurements were performed in triplicates. The 8-port data logger (Pico-TC08, England) and related software (PicoLog) were used to record the temperature data with 10s intervals.The full filled cans (without headspace) were statically heated in vertical position with no rotation. Numerical solutions of the governing equations were performed by COMSOL Multiphasics 4.2b software. A BDF method for time stepping and Backward Euler to time discretization were used. The system used to run the test and solve the equation was Intel VR CoreTM i5CPU M 460 @ 1.70 GHz and 6GB RAM. Numerical simulation of COMSOL software include spairing two physical phenomena: heat transfer and fluidflow. Since the system was cylindrical shaped can contain food with natural convection, non-isothermal laminar flow equationswere used. For this problem, one geometry and two domains were defined. The governing equations for non-isothermal laminar flow for domains were defined. Since in thermal diffusion analysis, the formula methods are more correct than empirical methods, formula methods were used in this study for calculating j and f. The accuracy of these calculations was evaluated using CFD. Parameter - f is the slope of heating curve. Jhindex, as a dimensionless correction factor. Results and discussion: The results showed that thecold area is near theone-tenth ofcans bottom. Inboth product initial temperatures, varying the concentration of the starch in product from 3.5 to 5% leads to longer heating time. The increase in the thermal process time at one-tenth of can bottom is more than one-third of can bottom. The time which the dispersion reaches to static temperature also changes with starch concentration in dispersion. The temperature difference in 5% starch dispersion at static temperature at the end of heating process is more considerable than 3.5% starch dispersion. Higher starch concentration induces a decrease in f (The fh coefficient represents thetime required to move heating process one cycle in heating curve and it can be calculated from the slope of the linear part of heat curve) at one-third of can bottom while an increase in f at one-tenth of can bottom. This behavior can be related to the fact that the starch gelatinization takes place earlier in one-third of can bottom than one- tenth due to the faster increase in temperature.
Azadeh Ranjbar Nedamani; Elham Ranjbar Nedamani
Abstract
The aim of this work was to study the antimicrobial activity of tomato skin lycopene oleoresin against Pseudomonas aeruginosa، Escherichia coli، Staphylococcus ureuse، Salmonella typh ، L. monocytogenes ، Bacillus cereus، Bacillus licheniformis. Oleoresin was extracted from tomato peel. Lycopene ...
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The aim of this work was to study the antimicrobial activity of tomato skin lycopene oleoresin against Pseudomonas aeruginosa، Escherichia coli، Staphylococcus ureuse، Salmonella typh ، L. monocytogenes ، Bacillus cereus، Bacillus licheniformis. Oleoresin was extracted from tomato peel. Lycopene content was measured by spectrophotometer. Lycopene oleoresin contained 2321mg lycopene/ 100 g oleoresin diluted in serial micro-dilution technique from 40,000 to 78.125 ppm. Microbial culturing was done in ELISA 96-well micro-titer plates in triplet and then MIC and MBC were determined. The results were shown that tomato peel oleoresin contained 2% lycopene, can inhibit and restrain the gram positive and negative bacteria.
Azadeh Ranjbar Nedamani; Yahya Maghsoudlou; Mohammad Ghorbani; Alireza Sadeghi Mahoonak
Abstract
Lycopene is a natural and dominant pigment in tomato with coloring and antioxidant properties, which nowadays the demands for its extraction enhancement from tomato and tomato products are increasing. In this study, the effect of pectinase enzyme pre-treatment at 2- 10 ml/kg and also washing with 94% ...
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Lycopene is a natural and dominant pigment in tomato with coloring and antioxidant properties, which nowadays the demands for its extraction enhancement from tomato and tomato products are increasing. In this study, the effect of pectinase enzyme pre-treatment at 2- 10 ml/kg and also washing with 94% ethanol at 60°C for 5 seconds was studied. In these conditions, treating with 10 ml/kg enzyme concentration at 90 minutes effective time resulted in maximum extraction of lycopene (279.5 mg/100g oleoresin) while for samples treated with pectinase and ethanol, maxmum extraction was 160.87 mg/100g olearesin. Also lycopene extraction yield from 100 g sample was 0.113609 and 0.089478 mg respectively. Totally in this study it was shown that pectinase treatment without ethanol treatment for extraction of lycopene is better in tomato waste.
