Bahman Saedpanah; Nasser Behroozi-Khazaei; Jalal khorshidi
Abstract
Introduction: Microwave-assisted extraction (MAE) is one of the newest techniques for extracting essential oils from medicinal plants. Microwave waves penetrate into plant cells and affect the polar molecules, causing heat to build up inside the plant tissue, destroying the cells and releasing the active ...
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Introduction: Microwave-assisted extraction (MAE) is one of the newest techniques for extracting essential oils from medicinal plants. Microwave waves penetrate into plant cells and affect the polar molecules, causing heat to build up inside the plant tissue, destroying the cells and releasing the active ingredients. Although in terms of essential oil extraction efficiency, MAE method is slightly higher than Clevenger, but in terms of energy consumption, process time and amount of solvent consumed has an inherent advantage over the Clevenger method. In this study, the aim is to evaluate the quantity and quality of rosemary essential oil in the developed microwave extraction system and process optimization in this system.
Materials and Methods: Rosemary plant (Rosmarinus officinalis L.) with 200 g used for each experiment. In this study, a microwave-assisted essential oil extraction system was developed. The system consisted of a home microwave, a distillation condenser, a cold-water source and a pump. In this study, the response surface methodology (RSM) used in the form of a central composite design with 13 treatments. The effect of two independent variables including power in the range of 300 to 900 watts and time in the range of 5 to 35 minutes on the efficiency of essential oil as dependent variables was investigated. To evaluate the quality of the extracted essential oil and compare it with Clevenger treatment, GC-Mass analysis was done using an Agilent technology apparatus (Agilent 7990B, USA).
Results and Discussion: A quadratic model was proposed for modelling of extraction efficiency and it was able to model with the values of R2, Adj R2 and Pred R2, which were 0.9521, 0.9180 and 0.574, respectively. The "Pred R2" of 0.547 is not as close to the "Adj R2" of 0.9180 as one might normally expect. The difference is more than 0.2. This may indicate a large block effect or a possible problem with the proposed model and/or data. Things to be considered for model modification are model reduction and response transformation. Results of ANOVA showed that only the linear terms of time, power and quadratic power of time are significant. The normal probability plot showed the normal distribution of errors observed in the experimental design space. The actual measured values R2 of the extracting efficiency from the experiments versus the values R2 predicted by the model indicated that this model could estimate the extracting efficiency with a correlation coefficient of 0.746. Box-Cox plot demonstrated for obtaining better results, the data of the amount of essential oil efficiency should be transferred to the power of 0.68 by the power function and the new model should be fitted to the data. Therefore, based on the Box-Cox diagram and the transfer of response data to the power space, as well as the use of a step-by-step method to remove meaningless terms from the model, the proposed model is as shown in equation 6. The results of the new model shows that the Pred R2 increased from 0.5574 to 0.8644, which indicates an
improvement in the performance of the new model. Alpha-pinene, camphene, borneol, camphor, cineole, and caryophyllene were the predominant compounds of the essential oil. In 300 and 600-watt treatments with a time of 35 minutes, the amount of dominant compounds of essential oil is slightly higher than Clevenger. However, in the power of 900 watts, due to the increase in temperature, some compounds have been destroyed and the extraction level of some compounds has decreased drastically, and in contrast, the level of caryophyllene was increased to 23.595 %, which indicates a sharp increase in its value at 900 watts. On the other hand, the components of alphapenine, camphor and cineole have the highest medicinal value, which according to Table 8, the highest values for these compounds have been extracted in 300 watt treatment. At the higher microwave power, due to the decomposition of the compounds, the amount of extraction of these compounds was significantly reduced. Also, at 300 watts, the extraction efficiency of these compounds was higher than that of Clevenger, which shows the ability of the MAE method in extracting essential oils from medicinal plants.
The results showed that the amount and quality of essential oil in the MAE with power of 300 and 600 watts was almost the same as Clevenger in most compounds. Essential oil compounds are degraded at 900 watts, so it is recommended not to use maximum power in the experiments. However, if the goal is to extract the highest amount of cariophylene, verbenone and cariophylene oxide in the extracted essential oil, higher power can be used.
Food Engineering
Mohsen Azadbakht; Bahareh Eshaghi; Ali Motevali; Azim Ghasemnezhad
Abstract
In this study, temperatures (40, 50, and 60°C), air velocity (3, 5, and 7 m/s) and pre-treatment (without pre-treatment, blanching, and microwave) were used as variables for investigation of antioxidant activity of dried artichoke leaves. The results revealed that variations in temperature and air ...
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In this study, temperatures (40, 50, and 60°C), air velocity (3, 5, and 7 m/s) and pre-treatment (without pre-treatment, blanching, and microwave) were used as variables for investigation of antioxidant activity of dried artichoke leaves. The results revealed that variations in temperature and air velocity of the drying chamber and different pre-treatments significantly affected the free radical scavenging level and total phenol content in this plant. Based on the results obtained, it can be concluded that by increasing the temperature and air velocity and using blanching and microwave pre-treatments, the free radical scavenging level and total phenol content increased. The maximum percentage of free radical scavenging was 72.08% at 60°C and an air velocity of 7 m/s in the drying state by using microwave pre-treatment. The maximum total phenol content was 3.55 mg/g of dry matter at 60°C and an air velocity of 7 m/s in the drying state by using microwave pre-treatment.
Food Chemistry
Mohammad Taghi Golmakani; Gholam Reza Mesbahi; Nasireh Alavi; Azita Hosseinzade Farbudi
Abstract
Introduction: Food wastes and losses are produced during all phases of food life cycles. The highest wastes belong to the processing of fruits and vegetables. Bioactive compounds have the potential to be extracted from the by-products of fruits and vegetables which can be used in the food processing. ...
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Introduction: Food wastes and losses are produced during all phases of food life cycles. The highest wastes belong to the processing of fruits and vegetables. Bioactive compounds have the potential to be extracted from the by-products of fruits and vegetables which can be used in the food processing. Extraction of flavor compounds, phenolic compounds, enzymes, and organic acids from wastes of fruits – pomace, peel, and seeds of citrus fruits, pomace and leave of apple, seeds of grape, and peel of kiwifruit – and vegetables – pomace of carrot, husk of garlic, skin of onion, peel of potato, and skin of tomato – have been reported (Sagar et al., 2018).Sour orange, Citrus aurantium, is one of the species of citrus fruits. Sour orange seeds contain fats, protein, and bitter compounds which affect citrus processing (Ye et al., 2017). Naringin, neohesperidin, flavon, caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid have been detected in methanolic extract of sour orange seeds (Bocco et al., 1998).Bioactive compounds are recovered from food wastes through various conventional and novel extraction techniques. Microwave-assisted extraction is one of the most used novel and environmentally friendly extraction methods. Advantages of microwave-assisted extraction over conventional extraction techniques include automated operation, more effective and selective heating, and less extraction time (Vinatoru et al., 2017).The objective of this study was optimization of microwave-assisted extraction of sour orange seed coat extract in terms of microwave power level, extraction time, sample quantity, and solvent volume on yield, bioactive compounds (total phenolic content and total flavonoid content), and antioxidant activity (free radical scavenging activity, ferric ion reducing antioxidant power, cupric ion reducing antioxidant capacity, and ferrous ion chelating). Also, optimum conditions of microwave-assisted extraction was compared to that of conventional magnetic stirrer-assisted extraction method. Materials and methods: Sour orange seeds were purchased from Limondis Company (Beyza, Fars province, Iran). Microwave-assisted extraction conditions including microwave power level (100, 200, and 300 W), extraction time (5, 10, and 15 min), sample quantity (5, 10, and 15 g), and solvent (methanolvolume 100, 150, and 200 mL) were optimized. Yield, bioactive compounds (total phenolic content (Habibi et al., 2015) and total flavonoid content (Habibi et al., 2015)), and antioxidant activity (free radical scavenging activity (Habibi et al., 2015), ferric ion reducing antioxidant power (Rekha et al., 2012), cupric ion reducing antioxidant capacity (Pascu et al., 2014), and ferrous ion chelating (Oyetayo et al., 2009)) of sour orange seed coat extract were evaluated. After determining the optimum conditions of microwave-assisted extraction, yield, bioactive compounds (total phenolic content and total flavonoid content), and antioxidant activity of sour orange seed coat extract were compared to those of conventional magnetic stirrer-assisted extraction method. Design Expert software (Version 10, Stat-Ease, Minneapolis, MN) was employed for analyzing four variables – microwave power level, extraction time, sample quantity, and solvent volume – at three levels consisting 30 experimental runs. Response surface methodology concerning central composite design (6 center points, quadratic model, and face center = 1) was applied. Results and discussion: Optimum conditions of microwave-assisted extraction were microwave power level of 200 W, extraction time of 12 min, sample quantity of 5 g, and solvent volume of 200 mL. Under optimum conditions, yiled, total phenolic content, total flavonoid content, IC50, ferric ion reducing antioxidant power, cupric ion reducing antioxidant capacity, and ferrous ion chelating were11.57%, 15550.50 µg gallic acid equivalent/g, 1476.22 µg quercetin equivalent/g, 11.33 mg/mL, 7.12 mg ascorbic/g, 6.44 mg ascorbic acid/g, and 0.43 mg EDTA/g, respectively. Intermediate microwave power level (200 W) can be more suitable from an industrial perspective and energy consumption (Jokić et al., 2012). Further increase in microwave power level, i.e. higher than 200 W, causes thermal degradation of bioactive compounds (Dahmoune et al., 2013), decreasing total phenolic content, total flavonoid content, and antioxidant activity of sour orange seed coat extract. The highest extraction time gives the bioactive compounds a chance to diffuse and release from the cell matrix to the surrounding environment (solvent). The highest solvent volume was selected as the optimum extraction condition. By increasing solvent volume up to 200 mL, meaning a greater gradient in bioactive compound concentration, mass transfer was also improved (Dahmoune et al., 2013). Also, the minimum sample quantity (5 g) was determined in optimum conditions. Increasing sample quantity (while the solvent volume remained constant) reduces the surface area available for the solvent to penetrate the sample matrix. As a result, higher sample quantity caused lower extraction of bioactive compounds (Ballard et al., 2010). There were no significant differences between yield, bioactive compounds, and antioxidant activity of extract obtained by conventional-assisted extraction method in comparison with those of microwave-assisted extraction. In conclusion, microwave-assisted extraction, as a green and fast method, can be proposed as a suitable and practical method for extraction of bioactive compounds from sour orange seed coat.
Mohsen Azadbakht; Mohammad Vahedi Torshizi; Fatemeh Noshad; Arash Rokhbin
Abstract
The orange samples were cut into slices with a thickness of 4 mm and treated with ohmic method for 3, 5, and 7 min as ohmic pre-treatment in three voltages 30, 50 and 70 V. Then, they were dried in three replicates using a microwave dryer and at three powers of 90, 360, and 900 W. The statistical analysis ...
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The orange samples were cut into slices with a thickness of 4 mm and treated with ohmic method for 3, 5, and 7 min as ohmic pre-treatment in three voltages 30, 50 and 70 V. Then, they were dried in three replicates using a microwave dryer and at three powers of 90, 360, and 900 W. The statistical analysis results showed that the ohmic time, ohmic voltage and microwave power are significant for the energy and exergy efficiency and specific energy and exergy loss at 1% level. The highest energy and exergy efficiency was observed at 900 W and in the ohmic time of 7 min. The highest energy and exergy efficiency was observed at 59.041% and 47.76%, respectively. The maximum energy loss was seen at 90 W and ohmic time of 3 min. The microwave power, ohmic time, and ohmic voltage were statistically significant for all the parameters (energy and exergy) such that with increasing them, the energy and exergy efficiency increased, while the specific exergy and energy loss decreased.
Nazanin Maryam Mohseni; Habibollah Mirzaee; Masoumeh Moghimi
Abstract
Introduction: Niger seed with scientific name of Guizotia abyssinica Cass from Asteraceae family is a dicotyledonous and one year plant that is one of the main and most important oil sources in Ethiopia and India. In different researches the amount of extracted oil from the seed of this plant has been ...
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Introduction: Niger seed with scientific name of Guizotia abyssinica Cass from Asteraceae family is a dicotyledonous and one year plant that is one of the main and most important oil sources in Ethiopia and India. In different researches the amount of extracted oil from the seed of this plant has been mentioned about 37 to 50 percent. The composition of fatty acid in this plant is similar to safflower and sunflower seed oil (of course with high percentage of Linoleic acid that may reach more than 85 percent). Generally, the mechanical press is one of the most popular methods for extracting oil from vegetable oil seeds all over the world. Increase in temperature will lead to more and faster extraction of oil from seeds and will increase the extraction efficiency. Microwave, is the non-ionized electromagnetic wave with frequency between 300 MHz to 300 GHz and are placed between the radio and infrared waves in the electromagnetic spectrum, consumers’ increasing demand for higher quality products and with minimized waste of nutrients in comparison with conventional thermal methods, caused an increase in use of non-thermal methods such as pulsed electric field methods. In current research it is tried to study the influence of pulsed electric fields and microwave pre-treatments on some characteristics of oil and meals obtained from Niger seed. Materials and methods: To perform this research, the Niger seeds (contain 40% oil) was prepared from local market of Fars Province (Iran). Then the external materials such as weed seeds, sand and stones were separated and removed manually and the seeds were treated with microwave pre-treatment with power of 900W and different procedure times (100 and 200 seconds), and pulsed electric field with two levels of electric field intensities of (250 and 500 kV/cm with 30 pulses). After performing these treatments, the seeds oil was extracted with screw press at the speed of 34 rpm then various experiments, such as the efficiency amount of oil extraction, refractive index, total phenolic compounds, oxidative stability, protein and ash of meals, were performed on the oil in a complete random model with three repetitions. Results and discussions: The comparing group mean test with Duncan’s method indicated that applying pulsed electric fields and microwave pre-treatments in lower times and intensities caused an increase in extraction efficiency. But with increase in the microwave time and also increase in the intensity of pulsed electric field, the efficiency of oil extraction was decreased in such a manner that when a pulsed electric field with intensity of 500 kV/m was used, the oil extraction had the lowest extraction efficiency. The increase of oil extraction efficiency using microwave can be related to more fracture or disintegration of cells which contain oil during treating with microwave. The reason for increase in the efficiency of oil extraction using the pulsed electric fields can be attributed to the electrical decomposition of cells and more permeability of them. A decrease in the oil extraction efficiency with excessive increase in the microwave time and intensity of electric field is probably attributed to more degradation of seeds internal structure and closure of oil outlet duct. Analysis of data obtained from oils refractive index indicated that the pre-treatment type didn’t have any significant influence on the oils refractive index (P>0.05) and the amount of refractive index was 1.478 for all of the measured samples (figure 2). Applying various pre-treatments, caused an increase in the amount of total phenol and oxidative stability of oils in the manner that the maximum amount of total phenol and oxidative stability was obtained from pulsed electric field pre-treatment with the intensity of 500 kV/m. The amount of tocopherol and antioxidant compounds can be the reason for this observation because of applying these pre-treatments. Variance analysis of data obtained from performing tests and experiments indicated that the influence of pre-treatment type on the amount of protein and meals ash was completely significant (P<0.01). Comparison of the means in data obtained from experiments showed that the maximum and minimum amount of protein and meals ash in the treated sample was obtained with 100 seconds microwave and the pulsed electric fields with 500 kV/m intensity, respectively, in other words, applying various treatments (in low times and electric field intensities of microwave and pulsed electric fields) in oil extraction led to an increase in the amount of protein and ash in comparison with non-treated sample and the reason of this fact can be attributed to the more extraction of oil from seeds and consequently an increase in the % protein and ash remained in the meals. Finally, the results of this research indicated that applying microwave (for 100 seconds) and pulsed electric field (with electric field intensity of 250 kV/m) can be very useful in extracting oil from Niger seed because of increase in the extraction efficiency and also increase of useful compounds in oil.
Mohammad Taghi Golmakani; Marzieh Moosavi-Nasab; Malihe Keramat; Azin Azhand
Abstract
Introduction: Wheat germ is a by-product of wheat milling industry. It contains about 11% oil. Wheat germ oil is well known as a tocopherol rich food lipid. It also contains more than 55% polyunsaturated fatty acids, mainly linoleic and alpha-linolenic acid (Simopoulos 1999; Schwartz et al. 2008). Wheat ...
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Introduction: Wheat germ is a by-product of wheat milling industry. It contains about 11% oil. Wheat germ oil is well known as a tocopherol rich food lipid. It also contains more than 55% polyunsaturated fatty acids, mainly linoleic and alpha-linolenic acid (Simopoulos 1999; Schwartz et al. 2008). Wheat germ processing presents challenges due to its high content of bioactive compounds. Microwave-assisted extraction is a new extraction technology used for the extraction of bioactive compounds, which is based on combination of microwave and conventional solvent extraction. This technique which is used has many advantages such as short time, less solvent usage, and higher extraction yield (Hao et al. 2002).Common Kilka (Clupeonellacultriventris caspia) oil is considered as one of the most healthy and functional oils. It is highly rich in polyunsaturated ω-3 fatty acids such as eicosapentaenoic acid and docosahexaenoic acid. However, Kilka oil is highly vulnerable to oxidation due to its high content of poly unsaturated fatty acids. Oxidations of poly unsaturated fatty acids such as eicosapentaenoic acid and docosahexaenoic acid result in a number of oxidation products that have negative impacts on the flavor and odor of Kilka oil, and also can affect the amount of these fatty acids that are made available to the body (Lin and Lin 2004; Fazli et al. 2009; Pazhouhanmehr et al. 2015; Yu et al. 2002). In order to preserve polyunsaturated fatty acids of Kilka oil from oxidative degradation, the use of novel and effective antioxidants can offer methods to maintain the health of consumers.The objective of this study was to investigate the effect of microwave-assisted extraction method on extraction yield and some chemical characteristics of wheat germ oil in comparison with conventional Soxhlet method. Also, wheat germ oil was investigated as a natural antioxidant for improving oxidative stability of Kilka oil.
Materials and methods: Wheat germ used in this research was supplied from Sepidan Flour Mill (Shiraz, Iran). Crude Kilka oil with no added antioxidants was supplied by a local fishery factory (Rasht, Iran).Wheat germ samples were pretreated with microwave at 200 W for 5 min. Thereafter, the samples were extracted with Soxhlet method. Samples were analyzed at 2, 4, 6, 8, and 10 h of extraction process. Extraction yield, saponification value, acid value, iodine value, and fatty acid profile of wheat germ oil extracted with microwave-assisted method were compared with those extracted with conventional Soxhlet method. Fatty acid composition of wheat germ oil was determined according to the method described by Golmakani et al. (2012) with some modifications. Saponification, acid, and iodine values of wheat germ oil were determined by using the AOAC official methods (AOAC 2000). Wheat germ oil was added to Kilka oil at a concentration of 1000 ppm. For the control, Kilka oil without any added antioxidant was used. Peroxide, anisidine, and Totox values of wheat germ oil were measured during 15 days storage at 60 °C. Peroxide, anisidine, and Totox values of wheat germ oil were determined using the AOCS official methods (AOCS 2000). Induction period was considered as the number of days required for a sample to reach a PV of 20 meq O2/kg (Keramat et al. 2016).
Results and discussion: The microwave-assisted extraction method increased the extraction yield of wheat germ oil by 15-27%. Increase in extraction yield is due to cell membrane rupture by microwave which results in greater porosity, enabling the passage of oil from the cell membrane (Uquiche et al. 2008). The amounts of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in samples extracted by microwave-assisted extraction method were similar to those extracted by conventional Soxhlet method. Acid value of samples extracted by microwave-assisted extraction method was slightly higher than those extracted by conventional Soxhlet method. This result is in agreement with the previous studies (Kiralan et al. 2014; Uquiche et al. 2008). The saponification value of wheat germ oil sample extracted by microwave-assisted extraction method was 9.65% higher than those extracted by conventional Soxhlet method. Thus, wheat germ oil sample extracted by microwave-assisted extraction method contained higher short chain fatty acids than those extracted by conventional Soxhlet method. The iodine value of wheat germ oil sample extracted by microwave-assisted extraction method was lower than those extracted by conventional Soxhlet method. Accordingly, microwave-assisted extraction method has a positive effect on the oxidative stability of wheat germ oil. Wheat germ oil significantly decreased the peroxide, anisidine, and Totox values of Kilka oil by 61.59%, 65.01%, and 61.97%, respectively, compared to the control. The induction period and protection factor of Kilka oil sample containing wheat germ oil (120.20 h and 1.42, respectively) was significantly higher than those of control sample (84.40 h and 1.00, respectively). The inhibitory effect of wheat germ oil against Kilka oil oxidation can be attributed to the presence of high amounts of biological active compounds. Based on the results of this study, microwave extracted wheat germ oil can be proposed as a natural antioxidant for improving oxidative stability of Kilka oil.
Hamid Bakhshabadi; Habibollah Mirzaee; Alireza Ghodsvali; Seyed Mahdi Jafari; Aman Mohammad Ziaiifar
Abstract
Introduction: Black Cumin seed (Nigella sativa L.) as one of the novel edible oil resources used commonly nowadays as seasoning in food product industries due to considerable medicinal properties and high nutritional impacts. Oil extraction by pressing method as an approach compared to other methods ...
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Introduction: Black Cumin seed (Nigella sativa L.) as one of the novel edible oil resources used commonly nowadays as seasoning in food product industries due to considerable medicinal properties and high nutritional impacts. Oil extraction by pressing method as an approach compared to other methods including solvent extraction is faster, safer and cheaper. In the oil extraction process, the preparation of the seeds is a substantial stage for obtaining oil with high quality and efficiency. Microwaves are electromagnetic waves that have a frequency ranged from 300 MHz to 300 GHz with corresponding wave lengths ranged from 1 mm to 1 m. On the other hand the artificial neural network as a powerful predictive tool in a wide scale of process parameters has been studied on an industrial scale in this research in order to achieve a simple, rapid, precise as well as effective model in the oil extraction of Nigella sativa L seed.
Materials and Methods: In the present study Black Cumin seeds after preparation including cleaning and passing resistance of the samples in front of air and moisture were stored in a plastic bag until the day of experiments. Then, they have been pre-treated with microwave within different processing times (90, 180 and 270 S) and powers (180, 540, and 900 W). Afterwards, seeds’ oil was extracted by screw rotational speed levels approach (11, 34 and 57 rpm). Different selected parameters including extraction efficiency, oil acidity value, color and oxidative stability were determined. To predict the alterations trend, the artificial neural network (ANN) design in MATLAB R2013a software was used.
Results and Discussion: According to MSE and R2 values obtained in this study, feed forward neural network with transfer function sigmoid hyperbolic tangent and Levenberg- Marquardt learning algorithm with topology of 3-10-5 (input layer with 3 neurons– a hidden layer with 10 neurons – output layer with 5 neurons) were selected as the optimal neural network with R2 more than 0.995 and MSE equal to 0.0005. Also, the results of the optimized and selected models were evaluated and these models with high correlation coefficients (over 0.949), were able to predict the changes' trend. According to the complexity and multiplicity of the effective factors in food industry processes and the results of this research, the neural network can be introduced as an acceptable model for modeling these processes. By determining the activation function in neural networks which was a function of sigmoid hyperbolic tangent in this study and also, with having the amounts of weight and bias, the connections created by the neuro-fuzzy model can be extracted. By defining this simple created mathematical equation, in computer software such as Excel, we can have a useful, simple and accurate program for predicting the desired parameters in the process of oil extraction by using microwave pre-treatment. Due to high accuracy of neural model we can trust the prediction of these models with high confidence, and this model can be used to optimize and control the process, which can lead to saving in energy and time, and on the other hand, can create a better final product.
Mehran Nouri; Behzad Nasehi; Vahid Samavati; Saman Abdanan
Abstract
Introduction: Increased awareness of diet-health association has led to the growth of health food industry. Deep-fat fried foods such as donuts enjoy wide popularity owing to their taste, distinctive flavor, aroma and crunchy texture. There is, however, a great health concern over large fat content of ...
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Introduction: Increased awareness of diet-health association has led to the growth of health food industry. Deep-fat fried foods such as donuts enjoy wide popularity owing to their taste, distinctive flavor, aroma and crunchy texture. There is, however, a great health concern over large fat content of fried foods. Incorporating the dietary fiber such as hydrocolloids into the food substrate in the batter formulation is one of the most effective strategies to decrease fat uptake in fried foods. Dietary fibers act as water binders in a coating or batter formulation through which reduce fat uptake of fried foods. That is, an increase of water content of food could lead to a decrease of oil penetration during the frying process. Persian gum (PG), as a novel gum, is exudates of the wild or mountain almond trees (the main source is Amygdalus scoparia Spach). Carrot pomace is a fibre-rich by-product of carrot juice industries which contains approximately 80% of carrot carotenes. Carrot juice yield is reported to be only 60-70% and the remaining pomace is usually disposed of as feed or fertilizer. There is an increasing interest in microwaving foods for several reasons: it is faster than conventional methods, the energy consumption is often lower and foods cooked by microwaving maintain nutritional integrity. Therefore, the aim of this study was to examine the effect of microwave pre-treatment on physico-chemical properties of donut containing Persian gum and carrot pomace powder sources of dietary fiber.
Materials and methods: Donuts were prepared according to the formulation reported by Melito and Farkas (2012). Ingredients used in control donut formulation were consisted of 100 g of wheat flour (9 g/100g), 38 g of water, 9g of Shortening, 13g of Egg, 13g of water for yeast, 6.3g of sugar, 6.3g of nonfat dried milk powder, 3g of active dried yeast, 1.6g of Vanilla extract, 1.6g of baking powder, and 1.6g of Salt. For the making of donuts, the flour blends were prepared by replacing wheat flour with 1.2 g/100g PG and 645 g/100g CPP. As well, water was added at 48.16 g/100g based on flour weight. The exudate gums of mountain almond trees were collected in Lorestan province. In order to eliminate foreign matters such as dust and dirt, the PG was washed three times with its threefold weight of ethanol (96% w/v) for 15 min under constant stirring. After removing ethanol by drying in an oven (at 60º C for 6 h) the PG was ground using a coffee grinder (model 320, Spain), sieved (180 µm) and packaged in polyethylene packs and then stored in 4ºC. Fresh carrots were purchased from a local market. Carrots were washed and then pressed with a juice extractor and the resultant pomace was collected. The carrot pomace was blanched in water (80 ± 2°C for 3 min) and then cooled in cold water (4º C). The pomace water was drained with cheese-cloth prior to drying. Finally, the carrot pomace was dried in an oven (60º C for 12 h). The dried pomace was ground using a coffee grinder to fine powder. The carrot pomace powder was sieved (180 µm) and packed in polyethylene packs and then stored in 4ºC. Specific volume of donuts was determined using the rapeseed displacement AACC method. Moisture content of donuts crumb was measured using a oven at 105 ºC for 3. The fat content of dried donuts was determined by Soxhlet extraction with petroleum ether for 5 h. Firmness and springiness were measured in triplicate using a TA.XT2i Texture Analyzer equipped with a 5 kg load cell and a P/35 mm aluminum cylindrical probe. Crumb grain (total number of cells and porosity) and crumb color of donuts were evaluated using an image analysis system consisted of a digital camera, a personal computer and MATLAB R2014a software. The control and optimized donuts were evaluated for acceptance of their appearance, crust color, crumb color, aroma, texture, taste and overall acceptance based on a nine-point hedonic scale. Response Surface Methodology (RSM) and Box-Behnken design with 3 factors were applied to obtain optimal levels of independent variables including microwave power (300-900 W), microwave time (30-90 s) and frying time (70-130 s).
Results and discussion: The results indicatedthat moisture content significantly (p
Mohammad Dolatabadi; Zeynab Raftani Amiri; Reza Esmaeilzadeh kenari
Abstract
Introduction: In recent years, much attention has been focused on agricultural wastes especially those containing phenolic compounds with natural antioxidant properties. One of these sources is the green husks of walnuts. The contents of phenolic compounds of plants are influenced under various factors ...
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Introduction: In recent years, much attention has been focused on agricultural wastes especially those containing phenolic compounds with natural antioxidant properties. One of these sources is the green husks of walnuts. The contents of phenolic compounds of plants are influenced under various factors including genetic factors, agricultural varieties and the species, climate and extraction procedures. Extraction is the first step for researchers who work on plants. Traditional extraction techniques with solvent such as water have disadvantages such as time consuming process, solvent consumption and high labor work. So the need to develop and use new extraction techniques, including combination of ultrasound bath and microwave devices, has provided valuable results. This method increases the mass transfer rate of the cell wall and intracellular compounds more rapidly transported out of the cell. In the ultrasound method to create cavitation in the extraction process and with collapse of bubbles and mechanical effects on the cell wall and most influential into the cell solvent improves the mass transfer. Extraction process performed by ultrasound process was used to facilitate the release of the intracellular content. These two methods can increase extraction efficiency within a shorter time and using less solvent, increasing the amount of extracted compounds are less damaging to the environment. Three different weather conditions for walnut production in northern Iran and different methods for extraction and measurement of phenolic compounds were adapted to find the best area and the most efficient extraction method.
Materials and methods: Three areas were selected from north parts of Iran including Bandar Gaz with mild climate, Shahrood with semi-arid climate and Hezarjerib region with mountainous climate located in the Alborz Mountain chains in which walnut is one of their major products. Walnuts randomly were picked by hand without any damage to their husks from a few walnut trees in a random garden in each region. The selected walnut trees were almost similar and were about 35 to 40 years old. In the selected areas, it is not conventional to use pesticides or chemicals and toppings for walnut trees. Walnuts collected were transported to the lab in cold conditions (8 to 10° C) and after cleaning the walnuts, green husks were separated and kept at -18 °C. Solvent extraction of phenolic compounds was carried out by choosing ethanol - water in a ratio of (1-1) by soaking, ultrasound and microwave methods at different times. The amount of phenolic compounds was measured using a spectrophotometer device with the aid of using the Folin Ciocalteau reagent, and antioxidant properties were measured using DPPH free radical scavenging and regenerative power of Iron III.
Results and discussion: This research was carried out on a factorial design (334) with three replications with Duncan's test for comparison of averages at the 95% confidence level. Comparing the extraction methods (soaking, microwave and ultrasound) showed that the most efficient method was ultrasound method at 30 minutes and the highest phenolic compounds in walnut green husk was for Hezarjerib area. In addition to the savings in time of extraction and safety in this method, the extraction of phenolic compounds is preferred to the other two methods. The results showed that the antioxidant properties were increased with increase in the amount of phenolic compounds. The results of this study also revealed that the walnuts green husks from Hezarjerib had the highest antioxidant properties followed by temperate region (Bandargaz) and semi-arid region (Shahrood).
Nina Daliri; Fariba Zeynali; Mohsen Esmaiili
Abstract
In this research the effect of oil type, process time ,temperature and pre-treating methods on moisture content, oil uptake, acidity and peroxide values of Zucchini slices (Cucurbita pepo. L) during deep fat frying process were investigated. The samples were pretreated by blanching (97 ºC for 5 ...
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In this research the effect of oil type, process time ,temperature and pre-treating methods on moisture content, oil uptake, acidity and peroxide values of Zucchini slices (Cucurbita pepo. L) during deep fat frying process were investigated. The samples were pretreated by blanching (97 ºC for 5 min) and microwave (900 W for 2min) methods before frying process. Frying experiments were carried out at two temperatures of 130 and 170 ºC for 7 and 4 minutes respectively by using two types of oil i.e. sunflower and special frying oils. The results showed that moisture content, oil uptake, acidity and peroxide values were significantly affected by temperatures, pretreatments and oil type (p
Ghasem Yousefi; Zahra Emam-Djomeh
Abstract
The present research surveyed the effect of five factors including: microwaves power, air temperatures and its flow rates, microwaving time onset and amount of substances on the requested time and energy for combined fluidized bed- microwaves drying of black raspberry into 50% dry base wet content. Response ...
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The present research surveyed the effect of five factors including: microwaves power, air temperatures and its flow rates, microwaving time onset and amount of substances on the requested time and energy for combined fluidized bed- microwaves drying of black raspberry into 50% dry base wet content. Response surface methodology and Central composite was used as experimental design. Multiple linear regression was used for obtaining second polynomials models for each analyses followed by ANOVA analysis in order to confirming the adequacy and accuracy of resulted models. Using the empirical resulted model the relationship between variables and responses were determined via response surface method. Correlation coefficients of the regression models were 0.964 and 0.970 respectively for the drying time and energy consumption. The Optimized drying condition were including; 600 watts for microwaves power and microwaving onset from that time as the moisture content was 344% decreased,73 g for amount of substances, and 85˚C and 15 m.s-1 for air temperatures and its flow rates respectively. Under mentioned conditions, the fitted model was predicted 52.66 Min and 65.2 Kj respectively for the requested drying time and energy consumption at combined drier. As a conclusion, the results showed that requested drying time and energy consumption were decreased with increasing of temperatures, microwaving time and its power, and decreasing of air flow rates. In this regard, the drying kinetics curve samples were drawn under the conditions listed that showed drying time is reduced to 76% with increasing temperature from 55 to 85 and use the microwave reduced drying time until 30 to 80%.
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.
Somayeh Rezai Erami; Seyed Mahdi Jafari; Morteza Khomeiri; Houman Bayat
Abstract
The aim of this study is extraction of phenolic compounds from walnut leaves of touyserkani variety with two extraction methods (traditional method and with microwave assisted extraction (MAE)) and evaluation of their antioxidant activity. Total Phenolic contents and antioxidant properties of aqueous, ...
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The aim of this study is extraction of phenolic compounds from walnut leaves of touyserkani variety with two extraction methods (traditional method and with microwave assisted extraction (MAE)) and evaluation of their antioxidant activity. Total Phenolic contents and antioxidant properties of aqueous, methanol (80%) and ethanol (50%) extracts in different times was determined. At the next stage, effect of methanol extract on retarding of oxidation of soy oil was assessed. All of extracts showed antioxidant activity in a concentration-dependent way. In MAE, methanol extract had highest total phenol whose content is 89.15 ± 0.25 mg/g. the ethanol extract presented highest activity in radical-scavenging activity (EC50 = 27.90 µg/ml), reducing power assay (EC50 = 93.26 µg/ml) and antioxidant activity assay (EC50=68.23 µg/ml). Also extract at 1000 ppm could control oxidation of soy oil and this extract was effective than all of synthesis antioxidant in retarding oil oxidation Hence we can present walnut leaves as a potential source of phenolic compounds and natural antioxidant.
