Atosa Assarzadegan; Mohammad Fazel
Abstract
Introduction: The fruit, with the scientific name of Cydonia oblonga comes from apple family, has a dry and fluffy flesh that, due to high vitamin C, Potassium and fiber has commercial and nutritional value. However, this fruit is as corruptible as other fruits and destructive microbial, chemical and ...
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Introduction: The fruit, with the scientific name of Cydonia oblonga comes from apple family, has a dry and fluffy flesh that, due to high vitamin C, Potassium and fiber has commercial and nutritional value. However, this fruit is as corruptible as other fruits and destructive microbial, chemical and mechanical factors that reduce its effective longevity. Enzymatic browning is a major problem for reducing the shelf life of freshly chopped fruits and vegetables. This reaction often occurs due to the activity of polyphenol oxidase (PPO) and peroxidase (POD) enzymes. Blanching is used to deactivate the relevant enzymes. Blanching is done before such processes as drying, canning, and freezing and somewhat determines the quality of the product. Sulfites are multi-functional compounds that inhibit enzymatic and non-enzymatic browning. Dehydration is one of the oldest techniques for keeping food products. Osmotic dehydration process has been emphasized in recent years due to the negative effects of conventional drying procedures, this process is done to partially remove the water from the plant tissue by immersion in a salt or salt solution. Chitosan is non-toxic, biodegradable substance that can be used as an edible coating to maintain the quality and increase the life after the fruits and vegetables harvest. This protective performance improves by adding antimicrobial, antioxidant. The lemongrass extract was added to the chitosan coating as antimicrobial. The purpose of this study is to investigate the effect of chitosan coating containing lemongrass extract on the shelf life of dehydrated quince fruit slices.
Materials and methods: Metabisulfite was used in order to prevent the browning reactions of slices prepared from blanching, water vapor and chemical solution of sodium. Then, quince slices are dehydrated with osmotic solutions of sorbitol, sucrose by immersion with chitosan containing (0, 0/5, 1 and 2 % lemongrass extract) coated and kept in sterile plates at refrigeration temperature (4±1˚C) for 4 weeks. The experiment was carried out in factorial method based on a completely randomized design with three iterations. Variables include the type of osmotic solution (sucrose, sorbitol) and coating treatments (chitosan coating containing 0, 0/5, 1 and 2% lemongrass extract). The studied characteristics included weight loss (%), acidity, pH, ascorbic acid concentration, total phenol, inhibitory activity of free radical (RSA), color properties (components L*, a*, b*, BI) of tissue that was investigated in the first, second, third and fourth week.
Results & discussion: Fruits coated with chitosan containing 2% lemongrass extract had less weight loss changes than other treatments. This can be due to the role of the extract in preventing decay, its antimicrobial properties and the formation of the semipermeable membrane by coating, which prevents weight loss. Edible coatings containing extract, by changing the internal atmosphere and reducing the respiration rate of the fruit, help to maintain better organic acids .Lemongrasses extract causes the delay in the consumption of organic acids in metabolic reactions, including respiration, due to its antioxidant properties. It seems increasing the pH of the fruit is the result of biochemical changes in the fruit during storage time, such as the decomposition of organic acids into sugars and participating the respiratory cycle in which the coating of chitosan containing extract can reduce the breakdown of organic acids by reducing respiration rate. The decrease in the drop of Vitamin C and phenolic compounds of the coated sample is due to oxygen permeation reduction and the creation of adapted atmosphere by coating. The high level of antioxidant activity of lemongrass extract is because of high phenolic compounds of which the highest amount was observed in treatment coated with chitosan containing 2% lemongrass extract. By increasing the concentration of the extract, its phenolic compounds increases which preserve more vitamin C and phenolic compounds and consequently antioxidant properties. Free radical inhibition activity was preserved due to better preservation of phenolic compounds, ascorbic acid and increasing the antioxidant capacity of fruit by chitosan coating containing lemongrass extract. The product brightness decreases during storage. Before the hot-water blanching coating process, sodium metabisulfite and osmotic dehydration have inactivated browning enzymes. Therefore, in quince coated with chitosan, the amount of color changes was not tangible due to the less respiration and as a result, less enzymatic activity of fruit. Coating containing lemongrass extract has created due to the color of coating extract with the green-tinted color. The increase in the extract concentration reduces the redness and increases the greenness of fruit, which is because of the extract color and as the effect increases, the concentration increases. By decreasing the brightness, increasing the greenness and yellowness during storage time and the browning increased. In quince coated with chitosan, the amount of softening wasn’t tangible due to less respiration and as a result, less enzymatic activity of fruit. As the concentration of lemongrass increases the stiffness of the tissue is reduced due to the effect of lemongrass on the fruit tissue cells that cause structural changes. Based on the results, the edible coating containing 2% lemongrass extract is suggested as the best formulation.
Nahid Jafari; Seyed Hamidreza Ziaolhagh; Abdorreza Mohammadi Nafchi
Abstract
Introduction: Potato is the fourth most important agricultural product after rice, wheat, and corn. Potato produces more dry matter, protein, and minerals per unit area in comparison with other crops. Many of the ingredients in potato are important, due to their beneficial effects on health. Hence, this ...
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Introduction: Potato is the fourth most important agricultural product after rice, wheat, and corn. Potato produces more dry matter, protein, and minerals per unit area in comparison with other crops. Many of the ingredients in potato are important, due to their beneficial effects on health. Hence, this product is very suitable for human consumption. Osmotic dehydration is used to remove a portion of water from foods such as fruits and vegetables, by immersion in high osmotic solutions such as sugars and salts. Osmotic dehydration is a relatively simple and economical process that improves the texture and rehydration properties of the products and prevents enzymatic browning by preventing the activity of polyphenol oxidases. In this process, the acid is removed and the sugar is absorbed, thus the composition of the fruits is changed and the taste and total acceptance of the product are improved. Osmotic dehydrating method has been used for drying various products such as carrots, mangoes, pineapples, strawberries, bananas, apples, apricots, and many other fruits. In this research, the effects of osmotic pre-treatment on qualitative and sensory properties of dried potatoes were investigated.
Materials and methods: In this study, Agria cv. potato samples were used and after washing, were completely peeled and cut into pieces of 3.5 × 0.5 × 0.5 cm. The treatments used in this study included osmotic solution concentration (at 0, 10 and 20% sodium chloride levels), osmotic solution temperature (30, 45 and 60°C), and immersion time in osmotic solution (at three levels 60, 240 and 720 minutes). The proportion of potato sticks to osmotic solution in all experiments was 1:6. After applying osmotic pre-treatment, samples were dried in an oven with a temperature of 60°C and a flow rate of 1.5 m/s to reach a moisture content of 8-10%. The moisture content, rehydration capacity, shrinkage, browning, color indices, and sensory properties (taste, color, shape, strength, and total acceptance) of potato samples were evaluated after the drying process and the response surface methodology (RSM) based on central composite design (CCD) were used to determine the optimal conditions for osmotic pre-treatment.
Results and discussion: The results of statistical analysis of the data showed that osmotic time and osmotic solution concentration had a significant effect on moisture content of potato slices. By increasing the time and decreasing the concentration of osmotic solution, moisture content of dried potato samples increased. The immersion time and osmotic solution temperature did not have any significant effect on the rehydration of potato slices, but the effect of osmotic solution’s concentration was statistically significant. By increasing the concentration of osmotic solution, the rehydration rate of potato samples decreased. The results showed that the interaction of temperature and concentration of osmotic solution had a significant effect on the degree of shrinkage of potato slices. Osmotic time and osmotic solution concentration had statistically significant effects on the browning index of potato slices, in a way that by increasing the concentration of osmotic solution, the browning index of potato samples decreased initially and then increased. The results of statistical analysis of the color indices showed that the osmotic solution temperature had a significant effect on the brightness (L*) of the potato slices, while the concentration of osmotic solution significantly affected their yellowness (b*) and the temperature and concentration of osmotic solution had a significant effect on the redness (a*) of the potato slices. By increasing the concentration of osmotic solution, the overall change in the color (E) of potato samples at high temperatures of osmotic solution first increased and then decreased. Sensory evaluation results showed that concentration, time, and temperature of osmotic solution had no significant effect on the sensory properties of potato sticks, except for taste. By increasing the temperature and time of immersion in osmotic solution, the taste scores of the samples increased. According to the results of optimization by the surface response method, the concentration of 2%, temperature of 46° C and dipping time of 173 min was introduced as favorable conditions.
Elham Azarpazhooh; Parvin Sharayei; Farzad Gheibi
Abstract
Introduction: The current study was carried out to investigate the kinetics of infusion of phenolic compounds extracted from grape pomace (Argol) into Aloe vera gel cylinders. Aloe vera gel was treated at 50 °C in different osmotic solution with (40, 50 and 60) % sucrose plus (10, 20 and 30) % Argol, ...
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Introduction: The current study was carried out to investigate the kinetics of infusion of phenolic compounds extracted from grape pomace (Argol) into Aloe vera gel cylinders. Aloe vera gel was treated at 50 °C in different osmotic solution with (40, 50 and 60) % sucrose plus (10, 20 and 30) % Argol, for 0–120 min. The fruit to solution ratio was kept 1:4 (w/w) during all experiments. A two parameters model was used for prediction of kinetics of mass transfer and values of equilibrium moisture loss and solid gain. Moisture and solid effective diffusivities were estimated using Fick’s second law of diffusion. Results showed that Azuara model has the potential for estimating the equilibrium points. In addition, a good correlation between predicted and experimental values were obtained by this model. Besides, moisture and solid effective diffusivities increased by increasing sucrose solution and Argol from 40 to 50 percentage and 10 to 20 percentages, respectively. Moisture and solid diffusivities were found in the range of 0.61–4.23×10−9 m2/s and 2.13 –2.77 × 10−9 m2/s, respectively. Functional food is an emerging field in food science due to its increasing popularity with health-conscious consumers and the ability of marketers to create new interest in existing products. New by-product application should be investigated to have a positive environmental impact or to turn them into useful products. The use of by-product such as the grape juice pomace (Argol), results in the return of these valuable sources into the food cycle as well as an improvement in nutritional value and functional products in the food industry. Red grape (Vitis vinifera L.) pomace contains a large amount of polyphenolic compounds, therefore extraction of bioactive compounds promote human health. It is not as easy to mix the functional ingredient in the solid system as it is, in the case of the powder and liquid products. With the help of osmotic dehydration, many researchers have demonstrated the infusion of active compounds such as mineral, phenolic compounds, curcuminoids, probiotics and vitamins into solid food tissue. Fruits such as aloe vera, which have a short shelf life and are suitable system models for infusion of phenolic compounds during osmotic dehydration. Osmotic dehydration can prove useful in drying aloe vera (Aloe Barbadensis Miller) which contains several nutritional compounds, including polysaccharides, phenolics, antioxidants, vitamins, enzymes, minerals, and so forth. The phenomenon of osmotic dehydration can be modeled by the fundamentals of mass transfer that describe the origin of the diffusive forces that are involved in and control these processes. A two-parameter equation of Azuara was used to predict the kinetics of osmotic dehydration and the final equilibrium point. The internal mass transfer occurring during osmotic dehydration of food is usually represented by Fick’s second law which is the best known phenomenological model to represent the diffusional mechanism is the model of Crank, consisting of a set of solutions of Fick’s law of diffusion for different geometries, boundary conditions and initial conditions. To date, there is no research on mass transfer during osmotic dehydration of aloe vera. Therefore, the objective of the present work was the infusion of Argol phenolic compounds in alo vera gel through osmotic dehydration treatment to investigate mass transfer during osmotic treatment.
Material and methods: The Aloe Vera was added to agar and shaped into cylindrical pieces (20×20 mm). Afterwards the pieces were floated in a solution of sugar (40, 50 and 60) percentage and Argol (10, 20 and 30) percentage. The weight ratio of osmotic medium to fruit sample was 4:1 to avoid significant dilution of the medium and subsequent decrease of the driving force during the process. The experiment was performed with constant temperature of 50 °C. Samples were removed from the solution at 30, 60, 90, 180, and 120 min of immersion, drained and the excess of solution at the surface was removed with absorbent paper. Afterward, the dehydrated samples from each group were drained and blotted with absorbent paper to remove excess solution. Each assay was made in triplicate. Weight and moisture content of the samples, and moisture loss (ML) and solid gain (SG) were calculated. The curves of moisture loss and salt gain as a function of time were constructed using experimental data. A two parameters model was used for prediction of kinetics of mass transfer and values of equilibrium moisture loss and solid gain. Moisture and solid effective diffusivities were estimated by using Fick’s second law of diffusion.
Results and discussion: Results showed that in all of the studied conditions, the levels of moisture loss and solid gain had a non-linear increase with more floatation time in the solution. Moreover, the absorption rate of solid gain was faster in the beginning but eventually slowed down. Azuara model has the potential in estimating the equilibrium points. In addition, a good correlation between predicted and experimental values was obtained by this model. Besides, increasing the concentration of sucrose and Argol from 40% to 50% and 10% to 20% respectively, the coefficient of effective penetration for both parameters (water loss and solid substance absorption) improved. In addition, the coefficient of effective penetration displayed that different levels of sucrose and Argol had a notable effect on this coefficient.
Elham Sadati gol afshani; Seyed Mahdi Jafari; Mahdi Kashani-Nejad; Shahram Beiraghi-Toosi; Mohammad Ganjeh
Abstract
Introduction: Osmotic dehydration involves the partial removal of water by direct contact of a product with a hypertonic medium such as high concentration of sugar, salt or sugar-salt solutions. In this process, food pieces are immersed in a hypertonic solution. The natural membrane of food cells acts ...
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Introduction: Osmotic dehydration involves the partial removal of water by direct contact of a product with a hypertonic medium such as high concentration of sugar, salt or sugar-salt solutions. In this process, food pieces are immersed in a hypertonic solution. The natural membrane of food cells acts as a semipermeable layer so the water moves across the membrane from an area of high water potential (low solute concentration) to an area of low water potential (high solute concentration), meaning the driving force for water removal is the concentration gradient between the solution and the intracellular fluid. During osmotic dehydration, osmotic solute is absorbed by food materials and has undesirable effects on water removal, nutritional and organoleptic properties. Use of coating improves the osmotic processing. Best factor for evaluation of coating material is performance ratio (WL/SG). So a coating should reduce solid uptake without negative effects on water removal.
Materials and methods: The apples (Golden delicious) used in this study were purchased from a local market in Mashhad (Iran) and stored at 4-6°C before processing. The sucrose (99.9%, Fariman sugar company, Iran), carrageenan (kappa type, Negin Khorak Pars Company, Iran), carboxy methyl cellulose (sandros, Japan) and calcium chloride (Dr. Mojallali Lab., Iran) were also used. In this work, apple cubes were single and double coated in three concentrations (0.5, 1 and 1.5% w/w) of carboxy methyl cellulose (CMC) and carrageenan solution and dehydrated osmotically in different concentrations (30, 45 and 60˚ BX) of sucrose solutions.
Results and Discussion: The results of this study indicated that increasing coating solution concentration from 0.5% to 1.5% decreased water loss. Also the water loss increased when the number of coating layers and the concentration of osmotic solution increased (from 30 to 60 ˚ BX). Generally, water loss and solids uptake in the samples coated with carrageenan was higher and lower than their CMC counterparts, respectively. The solids uptake in the samples coated with CMC increased by increasing the number of layers, osmotic solution concentration (from 30 to 60˚BX) and coating solution concentration (from 0.5 to 1.5%). The solids uptake increased and decreased with increase in layer number and coating solution concentration (from 0.5% to 1.5%), respectively. Increasing the osmotic solution concentration up to 45 ˚ BX increased solids uptake but, more increasingly did not have a significant effect on it. Finally, it cannot be said strictly that one coating type would facilitate osmotic process or not. It depends on various process factors. Among the 36 treatments studied in this research, the single coated samples with 1% carrageenan treated in 60 ˚ BX sucrose solution and the single and double coated samples with 0.5% CMC treated in 45 ˚ BX sucrose solution were the best, as they had 50% higher performance ratio than control (uncoated) sample.
Mina Kargozari; Morteza Jamshid EIni
Abstract
Introduction: The osmotically dehydrated carrots can be added directly into soups, stews or can be used in a broad range of food formulations including instant soups, snack seasoning and etc. Osmotic dehydration is a suitable way to produce the shelf-stable products or partially dehydrated foods ready ...
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Introduction: The osmotically dehydrated carrots can be added directly into soups, stews or can be used in a broad range of food formulations including instant soups, snack seasoning and etc. Osmotic dehydration is a suitable way to produce the shelf-stable products or partially dehydrated foods ready to place in other complementary processes such as air-drying, freezing and others. Modeling can certainly make differences in the food industry, leading to reduced costs and increased profitability. In food technology, at the simplest level, there are equations that determine the relationship between two or more variable. Simulation models in operation units and food preservation systems have attracted much attention in the past four decades. The mathematical equations describing mass transfer during osmotic dehydration, allow a better understanding of the composition of the material and operating parameters during dewatering. In this regard, many experimental and theoretical models have been reported in the literature but experimental models have more popularity because of easier applications. Regarding the classification of modeling in food processes, kinetic models are classified among theoretical models. It was ideal if we could use kinetic models based on fundamental scientific theories for the purposes of prediction and controlling the changes that occur in real food systems. But the complexity of the food makes the direct application of basic models impossible. The alternative is the direct study of kinetics on real food. As a result, the obtained models would be experimental or semi-experimental. Kinetics has developed as a powerful tool in modeling food quality features and in other words the modeling of food quality estimation is almost equivalent to the modeling of reaction kinetics in foods. The present study aimed to evaluate kinetics of osmotic dehydration of carrot cubes in terms of solid gain and water loss, which was studied at three glucose syrup concentration levels (30, 40 and 50% w/w), three salt concentration levels (5, 10 and 15% w/w) and three temperature levels of osmotic solution (30, 40 and 50°C) for 240 min. The experimental data were fitted to different semi-empirical kinetic models including Magee, Peleg and Page.
Materials and methods: Fresh well graded carrots were washed and peeled manually. A vegetable dicer was used to prepare carrot cubes of dimensions 1 cm× 1cm× 1 cm. The cubes were washed with fresh water to remove the carrot fines adhered to the surface of the fruit. The initial moisture content of the fresh carrot cubes varied from 86% to 90% (wet basis). Considering the greater effectiveness of a mixture of solutes over a single solute, a binary solution of salt and glucose syrup was used as the osmotic solution. The samples were excluded from the osmotic solution after 15, 30, 60, 120, 180 and 240 minutes. Carrot cubes were then washed with deionized distilled water, and were dried using a paper towel. Evaluation of mass exchange between the solution and sample during osmotic dehydration were made by using water loss and solid gain parameters. The experimental data were then fitted to different semi-empirical kinetic models including Magee, Peleg and Page which are widely used in biologic fields and the parameters of the models were determined. Data fitting was conducted using Microsoft Excel spreadsheet (Microsoft Office, 2010) using SOLVER add-in. Coefficient of determination (R2), chi-squared (χ2) and root mean square error (RMSE) were used to determine the best suitable model. An analysis of variance was conducted to determine the significant effects of process variables on solid gain and water loss.
Results and Discussion: At the beginning of the osmotic dehydration process, because of the high osmotic driving force between the concentrated solution and the fresh sample, the rate of water removal and solid gain was relatively high. Although water loss reached nearly the equilibrium conditions towards the late processing times, solid gain kept increasing. This increase in solid gain blocks the surface layers of the product, which reduces the concentration gradient between the product and osmotic solution, posing an additional resistance to mass exchange and lowering the rates of water loss at further processing times. It was also observed that while increasing the salt concentration, the solid gain in most of the samples significantly (p
Zeynab FarhaniNejad; Milad Fathi; Mohammad Shahedi
Abstract
Introduction: Banana is one of the most popular tropical fruits in all over the world with notable post-harvest losses. Due to its high moisture content preventing long preservation period. So, it needs a proper preservation method to prevent product lost especially in main produceing countries. Since ...
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Introduction: Banana is one of the most popular tropical fruits in all over the world with notable post-harvest losses. Due to its high moisture content preventing long preservation period. So, it needs a proper preservation method to prevent product lost especially in main produceing countries. Since banana is an un-freezable fruit, thermal processing such as drying or canning could be more appropriate for prolonging its shelf life. On the other hand, high energy consumption and being cost intensive are two most important disadvantages of thermal processing. In order to decrease the side effects of thermal process on quality parameters, pretreatment of samples could be applied to reduce time of main process.Osmotic dehydration is a non-thermal pretreatment which provides partial removal of water by immersing sample in an osmotic solution.But this process also takes a long immersion time to enough reduction of moisture. So this leads to undesirable effect on texture and colors.This study was performed to eliminate some side effects of osmotic dehydration on quality and finally introduce an optimized condition resulting best performance of process.A novel all-knowing method for optimization of process is genetic algorithm (GA) which is a search heuristic that mimics process of natural selection. It generates solutions for the optimization of problems using techniques inspired by natural evolution, such as inheritance, mutation, selection, and crossover. In this research, genetic algorithm was applied to predict optimum condition of osmotic dehydration.Material and methods: Osmotic dehydration was performed using aqueous solution of sucrose in concentration of 45% (w/w) for immersion time of 3 hr. The first challenge was improving mechanical properties of banana slices by adding calcium lactate to sucrose solution in concentrationsof 0, 2, 3 and 4%.For the next step in order to protect samples from enzymatic browning mixture of ascorbic acid (0.25 %) and citric acid (0, 0.5, 1, and 1.5%) were used.The pH of solution was measured for each level of adding citric acids. The efficiency of operation was estimated by computingwater loss and solid gain. Firmness of dehydrated samples wasmeasured using a texture analyzer (INSTRON, 1140, Singapore) and penetration test. Image acquisition technique was applied to measure L*, a* and b* indices.The coefficient of efficiency was defined as the ratio of water loss to solid gain and calculated to estimate performance of treatment in new condition. Finally, optimized conditionsfor maintaining the lowest solid gain and color changes, the highest water loss and firmness waterlosswere predicted by genetic algorithms method. The accuracy of model was investigated using statistical parameters such as mean absolute error (AME), normalized mean square error (NMSE),mean square error (MSE).Results and discussion: The results of experiments showed a significant increase of firmness by adding lactate calcium. This observation was due to complex formation between calcium and cell wall ingredients. Thesecomplexes have a decreasing effect on solid gain.Because complexes preventedmacromoleculesentering such as sucrose to the cells.On the other hand,calcium lactate and citric acid had interaction on mentioned parameters.Firmness showed less firmness when citric acid was added to the solution. Because citric acid as a chelating agents can blockdivalent cations and prevent from effective reaction with plant cells.Also citric acid can disconnect methoxyl groups from protopectinproducing softer texture.However, treated samples still showed firmer texture than control sample. It could be due to the additional effect of citric acid which makes carboxyl groups available for divalent calcium cations during conversion of protopectin to the pectin.For color parameters,only use of citric acid could not decrease the total change of color because yellow index increased due to the hydration of citric acids. But for the use of two factors, a significant decrease of total change of color was observed.For water loss, increase of solvents in each treatment led to raise of water loss due to the increase of osmotic pressure.In this circumstance determination of suitable concentration for each factorresulting best performance is complex, so it is necessary to apply a system canpredict optimized conditions. Genetic algorithms estimated optimum condition formaximum firmness and water loss, minimum solid gain and total change of color.In this condition the concentrations of lactate calcium and citric acid were %3.99 and %0.86, respectively. Also predicted values for water loss, solid gain, firmness and total change of color were earned %18.01, %5.07, 1.47 N and 11.37.MAE, NMSE and AME parameters (2.062, 0.021, and 1.099 respectively) were used for investigation of difference between estimated and experimental data which showed high efficiency of genetic algorithm for optimization of osmotic dehydration of banana.Investigating the efficiency ofcoefficient of treatments showed that application of both factors (calcium lactate and citric acid) significantly had more efficiency in comparison to the control samples regarding quality factors.
Mahdi Irani; Masoud Shafafi; Hasan Irani
Abstract
This paper presents a novel approach to monitor food process based on Modular Neural Networks (MNNs) and fuzzy inference system. The proposed MNN consists of three separate modules, each using different image features as input including: edge detection, wavelet transform, and Hough transform. The sugeno ...
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This paper presents a novel approach to monitor food process based on Modular Neural Networks (MNNs) and fuzzy inference system. The proposed MNN consists of three separate modules, each using different image features as input including: edge detection, wavelet transform, and Hough transform. The sugeno fuzzy inference system was used to combine the outputs from each of these modules to classify the images of quince during osmotic dehydration process. To test the method, for classification, database was made of 108 quince samples’ images (12 classes). In experiments, the developed architecture achieved 91.6% recognition accuracy. Next step, solid gain, water loss and moisture content of quince samples were considered as MNNs outputs, whereas osmotic dehydration time and classified images were MNNs inputs. The minimum %MRE (18.153) with 89% prediction ability for water loss (WL) was obtained when applying two hidden layers with 6 neurons per each two layers. The lowest %MRE (35.5335) with 93% prediction ability for solid gain (SG) was obtained when using 6 and 8 neurons per first and second layer, respectively. And finally %MRE was at least (7.4759) with 96% prediction ability for moisture content (MC) by 6 and 5 neurons per first and second layer, respectively. The results show that this model could be commendably implemented for quantitative modeling and monitoring of food quality changes during osmotic dehydration process.
Mahdi Barmour; Jalal Dehghan nia; Babak Ghanbarzadeh
Abstract
The objective of this study was to evaluate the effect of process conditions and different pretreatments including ultrasound, microwave and osmotic dehydration on mass transfer and oil uptake during deep fat frying of potato slices. Ultrasound pretreatment was performed at frequency of 40 KHz for 10 ...
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The objective of this study was to evaluate the effect of process conditions and different pretreatments including ultrasound, microwave and osmotic dehydration on mass transfer and oil uptake during deep fat frying of potato slices. Ultrasound pretreatment was performed at frequency of 40 KHz for 10 and 30 minutes, microwave pretreatment was conducted at 5 W/g power and osmotic dehydration pretreatment was done in NaCl solutions with concentrations of 1 and 3 percent. Potato slices were then fried at 150, 170 and 190°C for 90, 180, 270 and 360 seconds. The results showed that ultrasound pretreatment for 10 minutes increases oil uptake of samples as compared with control sample, but when samples were exposed to ultrasound for 30 minutes, oil uptake was decreased. In addition, microwave pretreatment reduced oil uptake of potato slices insignificantly. Furthermore, osmotic dehydration pretreatment reduced oil uptake. In order to model oil uptake, experimental data were fitted with 6 models. The aforementioned models had the highest R2 and a minimum value of RMSE.
Hamed Fatemian; Shadi Giahchi; Seyed Ebrahim Hosseini; Abbas Gerami
Abstract
Food dehydration process in several reasons, causes deteriorate qualitative characteristics in final products. It is necessary to use some pretreatments such as osmotic dehydration. In this research, during osmotic dehydration of pear rings, the effects of concentration of sucrose solutions of 50 and ...
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Food dehydration process in several reasons, causes deteriorate qualitative characteristics in final products. It is necessary to use some pretreatments such as osmotic dehydration. In this research, during osmotic dehydration of pear rings, the effects of concentration of sucrose solutions of 50 and 60 percent (w/w), in constant temperature of 30ºC, and reconstitution of osmotic solutions (until 5 times), were investigated on quantitative and qualitative characteristics of osmotic samples, such as pH, hardness, color of texture, total sugar and moisture content of osmotic samples and pH, turbidity, viscosity of solution osmotic. The result showed that with increase concentration osmotic solution and reconstitution of osmotic solutions pH of sample and solution is increase and decrease respectively. It’s because of increase the moisture content and extraction acids from texture of osmotic sample. Also reconstitutions of osmotic solutions will cause increase the turbidity in solution, that reason is increase the production of pigment in solution. Also increases the density of osmotic solutions may cause increase the color of osmotic samples and we can say that the reason is extraction of colorful compound from texture of sample. The most reason of hardness of texture is related to a sample that it processed in a solution that is 5 times concentrated. Finally the coated sample that was osmotic dehydrated and fifth reconstituted solution was known as the superior sample.
Emad Aydani; Mahdi Kashani-Nejad; Mohsen Mokhtarian; Hamid Bakhshabadi
Abstract
In this study, Response Surface Methodology (RSM) was used to optimize osmo-dehydration of orange slice. Effect of osmotic solution temperature in the range of 30 to 60 °C, immersion time from 0 to 300 min and sucrose concentration from 35 to 65 brix degree on water loss, solid gain, moisture content, ...
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In this study, Response Surface Methodology (RSM) was used to optimize osmo-dehydration of orange slice. Effect of osmotic solution temperature in the range of 30 to 60 °C, immersion time from 0 to 300 min and sucrose concentration from 35 to 65 brix degree on water loss, solid gain, moisture content, water loss to solid gain ratio and brix change were investigated by Central Composite Design (CCD). Applying response surface and contour plots optimum for osmotic dehydration were found to be at temperature of 30 °C, immersion time of 229.2 minute and sucrose concentration of 65%. At this optimum point, water loss, solid gain, WL/SG ratio, moisture content (dry base) and brix difference were found to be 30.316 (g/100 g initial sample), 13.51 (g/100 g initial sample), 2.45, 2.77 % and 15.79, respectively. The result of artificial neural network indicated that the perceptron neural network with one hidden layer is able to anticipate the dehydration characteristics. This network predicted solid gain and moisture content with 5 neuron per hidden layers with R2 values of 0.937 and 0.959, respectively and brix difference and water loss with 30 neuron per hidden layer with R2 values of 0.961 and 0.942, respectively.
Mina Akbarian; Babak Ghanbarzadeh; Jalal Dehghan nia; Mahood Sowti Khiabani
Abstract
In this study, the optimization of osmotic solutions (containing fructose, calcium chloride and citric acid) were investigated based on maximum water loss (WL) in the osmotic dehydration of quince. The response surface methodology (RSM) and central composite design, with 18 treatment and 3 replicate, ...
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In this study, the optimization of osmotic solutions (containing fructose, calcium chloride and citric acid) were investigated based on maximum water loss (WL) in the osmotic dehydration of quince. The response surface methodology (RSM) and central composite design, with 18 treatment and 3 replicate, was used for optimizing. The results showed that fructose and calcium chloride had linear and quadratic significant effects (p
Azam Seraji; Babak Ghanbarzadeh; Mahood Sowti Khiabani; Sara Movahhed
Abstract
In this study, the effect of edible coating and osmotic dehydration, as pre-treatments before drying of cucurbit, were investigated. Cucurbit samples were cut spirally and coated by carboxy methyl cellulose (CMC) 1% and ascorbic acid 0.1% solutions and then processed by osmotic dehydration. Proportion ...
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In this study, the effect of edible coating and osmotic dehydration, as pre-treatments before drying of cucurbit, were investigated. Cucurbit samples were cut spirally and coated by carboxy methyl cellulose (CMC) 1% and ascorbic acid 0.1% solutions and then processed by osmotic dehydration. Proportion of sample to solution was 1:10 and the solution containing sucrose %45, salt%25 and citric acid %1 (W/W) was selected as the best osmotic solution. Finally, the cucurbit samples were dried by oven (at 80 ˚C for 3 hours). The effects of CMC based coating on water loss (WL), solid gain (SG), immersion time, amount of salt, sucrose, citric acid absorption and color and sensory acceptability of samples were evaluated. The results showed that CMC based coating decreased SG without decreasing effect on WL which in turn decreased drying time of osmotic dehydrated samples in oven. Furthermore, the coated, osmotic dehydrated samples showed higher color quality and sensory acceptability in comparison to the control samples.
