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.
Hamid Bakhshabadi; Mohammad Rostami; Masoumeh Moghimi; Abolfazl Bojmehrani; Anehbibi Bahelkeh; Negar Toorani
Abstract
Introduction: Using oilseeds in the human food stuffs, employing their meal for animal feed and also their usage in pharmaceuticals, soap making and fuel has prompted great interest for farmers to plant them and for the government to promote their cultivation. Among them, sunflower is one of the main ...
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Introduction: Using oilseeds in the human food stuffs, employing their meal for animal feed and also their usage in pharmaceuticals, soap making and fuel has prompted great interest for farmers to plant them and for the government to promote their cultivation. Among them, sunflower is one of the main oilseeds in the world which its cultivated area has expanded due to fair cultivation requirements, high yield of the oil, high nutritional value and also lack of anti nutritional factors. Sunflower (Helianthus annuus) is an annual plant belonging to Asteraceae family. This is a dicotyledonous, cross-pollinated monoecious plant that is fertilized by wind and insects. Sunflower seed oil has an excellent nutritional quality, as in recent years, cultivars with high oil (especially oleic acid) content have been substantially nurtured. The most different methods of extracting oil from oilseeds are the press and solvent methods. Similar to the other seeds with high oil content such as canola, the most effective way of extracting oil from sunflower is mechanical pressing followed by solvent extracting. In this method, the mechanical press extracts about 60 percent of the oil and the solvent method extracts the remaining oil. For the first time, the present study was aimed to improve temperature of cooker and moisture of output seeds for producing sunflower oil with lowest degree of insoluble fine partial in oil, moisture and acidity and meal with lowest levels of moisture and oil. Materials and Methods: Sunflower seeds used in this research were supplied from one of Iran's provinces and were transferred to the company of Khorasan cotton and oilseeds to produce oil and meal. After receiving the sunflower seeds in the factory, they were entered into silos in dark and ambient temperature; impurities such as dust, sands, stones, spoiled seeds, small weed seeds and other extraneous materials were separated by mechanical sieves. After cleaning, the seeds were entered into the cracker and they were broken into smaller particles and then were moved into the cooker; at this stage, the temperature of cooker and moisture content of the exiting seeds were set to 70, 80 and 900 C, and 7, 7.5 and 8%, respectively. Then, conditioned seeds were entered into the Buhler flicker device for flaking. Afterwards, the flakes were moved into the Desmet extractor (heating condition of 500C for 7 hours) to extract the oil from the seeds by hexane solvent. Then, the tests were performed on the oil and meal. Severalphysic-chemical properties of sunflower oil including insoluble fine partial, acidity values as well as moisture, protein and oil contents of the obtained meals were determined. Statistical analysis and process optimization were carried out using response surface methodology (RSM). Results and discussion: The achieved results expressed that with an increase in cooking temperature, insoluble fine partial and oil acidity values of the extracted oil were boosted while moisture content of oil and meal values alongside oil content of the obtained meal showed reduction. With increasing of the moisture content of cooker’s seeds, the insoluble fine partial value of the extracted oil was reduced while oil acidity value was increased. Increasing the moisture of cooker’sseeds led to the oil reduction in the meal. The highest oil content in the meal was achieved in the condition that the cooker temperature was 70oC and the moisture of output seeds from the cooker was 7%. The analysis of resulted data showed that two parameters of the cooker’s temperature and cooker’s seeds moisture content had significant effects on the moisture content of the meal. Increasing the cooker temperature from 70 to 90oC caused a decrease in the meal moisture. As result shown, increasing the moisture content of output seeds from the cooker increased the moisture content of the meal. Increasing the cooker temperature from 70 to 90oC reduced the protein amount of the meals. Results of different studies showed that increasing the temperature will decrease the protein amount of the meals. Increasing the moisture was also resulted in the decrease of residual protein in the meal. The obtained results of the optimization procedure revealed that the application of the cooking temperature of 70 °C and moisture content of the output seeds equal 7.73 and 7.65 % led to achieving products with the least values of acidity and insoluble fine partial in the obtained oil as well as meals with the minimum remaining oil.
