Food Chemistry
Somaye Kheirati Rounizi; Fateme Akrami Mohajeri; Hamdollah Moshtaghi Broujeni; Sara Jambarsang; Hossaein Kiani; Elham Khalili Sadrabad
Abstract
Background and objective It was shown that contamination of agricultural pasturage with fertilizers, application of sewage and effluents in irrigation, use of pesticides and air pollution have led to the entrance of chemical contaminants, including metals, into plants. On the other hand, food processing ...
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Background and objective It was shown that contamination of agricultural pasturage with fertilizers, application of sewage and effluents in irrigation, use of pesticides and air pollution have led to the entrance of chemical contaminants, including metals, into plants. On the other hand, food processing is (handling, processing, transportation) considered as an important way of food contamination. Vegetable oils are essential in human dietary which is introduced as crucial sources of energy, fat soluble vitamins, and essential fatty acids. Sesamum indicum L., known as sesame seed, has been cultivated in Asian countries from ancient times as vegetable oil for cooking and seasoning ingredients. In recent years, the sesame oil has been considered due to its high antioxidant activities and nutritional properties. Due to the use of sesame seeds extracted oil in two form of ardeh oil and sesame oil, the amounts of mineral elements (phosphorus, potassium, iron, nickel, cobalt, manganese, calcium and magnesium) in sesame seeds and its extracted oils (ardeh oil and refined sesame oil) were investigated. Materials and Methods In order to determine the mineral concentration, refined sesame oil and ardeh oils were prepared from an imported sesame seed. In order to prepare the sesame oil, sesame seeds were put into a cold presser and the oil was extracted under low pressure. The Ardeh oil was prepared by adding water to sesame paste in the ratio of 2.2:10 and oil was separated by centrifugation. The sesame seeds and oil samples (refined sesame oil and ardeh oils) were digested by microwave digestion method in presence of 5 ml 65% nitric acid and 2 ml of hydrogen peroxide (H2O2). The digested samples were then filtered through 0.45 µm filter membrane. Then, the concentrations of phosphorus, potassium, iron, nickel, cobalt, manganese, calcium and magnesium in sesame seeds, ardeh oil and refined sesame oil were examined using Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP – OES). Results In the present study, the limit of detection (LOD) for each studied mineral elements were determined as nickel: 4 mg/kg, magnesium: 0.00066 mg/kg, manganese: 0.000134 mg/kg, phosphorus: 0.384 mg/kg, cobalt: 0.594 μg / kg, iron: 0.000797 mg/kg, potassium: 0.00394 mg/kg, calcium 0.005 mg/kg. According to the results, the highest amounts of mineral elements were detected in sesame seeds. The achieved results showed that the method of sesame oil extraction can reduce the mineral elements in the final sesame oils. The amounts of mineral elements in sesame seeds were estimated as P > Ca > K > Mg > Fe > Mn > Co > Ni. The pattern of mineral elements in Ardeh oil was reported as P > Fe > K > Co > Mg > Ni > Mn > Ca. The reduction pattern was reported as P > K > Fe > Ni > Co > Mn > Ca > Mg in refined sesame oil. As can be seen the order of mineral elements was changed in two oil samples and sesame seed. It was shown that except for K and Ca, all mineral elements in ardeh oil were higher than refined sesame oil. As can be seen, the refining process was effectively reduced the metals in oil samples. On the other hand, high amount of mineral elements in sesame seed in comparison to extracted oils could be attributed to lack of processing methods which are present in oil production in both methods. Conclusion It should be considered that presence of different metals in vegetable oils could facilitate the oil deterioration and oxidization as well as oil shelf life reduction. Since the most of the sesame lots in Iran are imported, it is necessary to monitor the amount of mineral elements.
Food Chemistry
Masoumeh Heydari Gharehcheshmeh; Akram Arianfar; Elham Mahdian; Sara Naji-Tabasi
Abstract
[1]Introduction: Sesame oil and sweet almond oil are rich in unsaturated fatty acids and antioxidant components, providing nutritional and functional properties including improvement of the gastrointestinal system, decrease in blood cholesterol level, eventually leading to a decrease in the risk of cardiovascular ...
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[1]Introduction: Sesame oil and sweet almond oil are rich in unsaturated fatty acids and antioxidant components, providing nutritional and functional properties including improvement of the gastrointestinal system, decrease in blood cholesterol level, eventually leading to a decrease in the risk of cardiovascular disease. The present study examined the possibility of the production of emulsion based on sesame and sweet almond oils and the effect of preparation on its stability. Material and methods: Sesame oil and sweet almond oil with tween 80 and span 80 as emulsifiers were used in emulsion production. In order to prepare the nanoemulsions, the water and oil phases were prepared separately by the ultrasonic homogenizer. Ultrasonic waves were applied for homogenization and the effect of Ultrasonic time (5, and 10 min), oil content (2, and 4%), and emulsifier concentration (0.25, 0.5%) on particle size, particle distribution index (PDI), turbidity loss rate, emulsion stability and zeta potential of nanoemulsions were studied. Results and discussion: Ultrasonic time had a reverse effect on particle size, particle distribution index (PDI) and turbidity loss rate and a direct effect on emulsion stability. The particle size and turbidity loss rate of prepared emulsions had a direct relation with oil concentration and a negative effect on emulsion stability. Emulsifier concentration had a positive effect on emulsion stability, a negative effect on emulsion stability, and had no significant effect on turbidity loss rate. According to the results of the effect of type and concentration of oil on particle size distribution, turbidity reduction rate and stability of nanoemulsions in all cases, samples containing sesame oil with a concentration of 2% compared to sweet almond oil, had better results, the presence of this oil led to the formation of nanoemulsions with smaller particles and greater stability. The produced nanoemulsions had a particle size between 200-320 nm, a stability of 91-98/7% and a turbidity reduction rate of 0.0010-0.0027. Also, the highest stability and zeta potential were reported 98.7 % and -33mV respectively, which belonged to sample k4. Therefore, this sample was selected as the optimal sample.The results showed that the particle size, mean particle diameter, particle dispersion and turbidity reduction rate showed a significant difference between the samples, so that the lowest and highest were related to K4 sample (2% sesame oil, homogenization time 10 minutes and Emulsifier concentration ratio 0.5%) and sample B5 (almond oil 4%, homogenization time 5 minutes and emulsifier concentration ratio 0.5%) (p <0.05). The results also showed that the highest level of stability and zeta potential was related to K4 sample. Thus, the best nanoemulsion, K4 sample was introduced
Sedigheh Yazdanpanah; Sara Mohammadi; Amir Hossein Elhami Rad
Abstract
Introduction: White tea is a new ingredient in a wide range of phenolic, antioxidant and antimicrobial compounds. The most important catechins in white tea are epicatechin, epigallocatechin, epicatechin- 3- galate, and epigallocatechin- 3- galate, which are flavonol gallates. The concentration of these ...
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Introduction: White tea is a new ingredient in a wide range of phenolic, antioxidant and antimicrobial compounds. The most important catechins in white tea are epicatechin, epigallocatechin, epicatechin- 3- galate, and epigallocatechin- 3- galate, which are flavonol gallates. The concentration of these phenolic compounds in white tea is higher than green tea. Sesame seed oil, which is produced by cold pressing method, has a great ability to preserve antioxidant compounds. Significant oxidative stability of sesame oil is due to the presence of lignan non-soapy substances. Strong antioxidant compounds in sesame seed oil include sesamol, sesamulin (antioxidant precursor), sesaminol and its isomers. The aim of this study was to investigate the effect of natural antioxidants of sesame oil and white tea on inhibiting the effect of metals on oxidation of sesame oil. Materials and Methods: In this study, aqueous extract of white tea was extracted and sesame oil was produced using cold press. In the next step, six samples including control sample (sesame oil), sesame oil containing white tea extract, sesame oil containing white tea extract and 0.1 ppm iron, Sesame oil containing white tea extract and 0.1 ppm copper, sesame oil with tea and 0.1 ppm zinc extract and sesame oil containing 100 ppm BHT were prepared. In all samples, aqueous extract of white tea in the amount of 6 mg/ 10 g was added to sesame oil. Total phenol, antioxidant capacity, power reducing on white tea extract and antioxidant power, peroxide number, oxidation stability and fatty acids profile were measured. All experiments were performed in a completely randomized design with three replications and the means were compared with Duncan’s test at the level of (P<0.05). SAS V 9.1 software was used for statistical analysis of quantitative data. Results and Discussion: The results showed that the aqueous extract of white tea contained 4.06 (mg gallic acid per gram of sample) total phenol, 6.00 (μg/ ml) antioxidant capacity 0.020 (mg/ g). Ml) is a reducing power. The reducing power of BHT antioxidant was 40 times and the antioxidant power of BHT was 14.85 times more than the aqueous extract of white tea. In the inhibition of free radicals in sesame oil, the aqueous extract of white tea had a significantly greater effect than the control sample. The iron- containing sample had more oxidation than other samples. In the inhibition of free radicals in sesame oil, the aqueous extract of white tea had a significantly greater effect than the control sample. The iron- containing sample had more oxidation than other samples. Rancimat value for samples of control sesame oil, sesame oil with tea and iron extract, sesame oil with tea and copper extract, sesame oil with tea and zinc extract, sesame oil with tea extract and sesame oil with synthetic antuioxidant BHT respectively 8.79 4.80, 9.08, 9.35, 9.42 and 9.61 hours were measured. The highest stability was related to the sample of sesame oil and synthetic antioxidant BHT and the Results and Discussion: The results showed that the aqueous extract of white tea contained 4.06 (mg gallic acid per gram of sample) total phenol, 6.00 (μg/ ml) antioxidant capacity 0.020 (mg/ g). Ml) is a reducing power. The reducing power of BHT antioxidant was 40 times and the antioxidant power of BHT was 14.85 times more than the aqueous extract of white tea. In the inhibition of free radicals in sesame oil, the aqueous extract of white tea had a significantly greater effect than the control sample. The iron- containing sample had more oxidation than other samples. In the inhibition of free radicals in sesame oil, the aqueous extract of white tea had a significantly greater effect than the control sample. The iron- containing sample had more oxidation than other samples. Rancimat value for samples of control sesame oil, sesame oil with tea and iron extract, sesame oil with tea and copper extract, sesame oil with tea and zinc extract, sesame oil with tea extract and sesame oil with synthetic antuioxidant BHT respectively 8.79 4.80, 9.08, 9.35, 9.42 and 9.61 hours were measured. The highest stability was related to the sample of sesame oil and synthetic antioxidant BHT and the lowest stability was related to the sample of sesame oil with tea and iron extracts. In comparison with the effect of metals on the oxidation of sesame oil, the addition of iron to sesame oil has increased the oxidation rate compared to the two other examined metals (copper and zinc). Rare metals increase the oxidation rate of edible oils by increasing the production of free radicals from fatty acids or hydroperoxides. The composition of of fatty acids profile showed that palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid were the predominant fatty acids in sesame oil. In the iron- containing sample, with increasing oxidation rate, the amount of linolenic acid decreased compared to other samples. The results of the Se index were confirmatory on the results of oxidative stability index. White tea extract and sesame oil due to their antioxidant and phenolic compounds have been able to inhibit free radicals and metal peroxidants, especially copper and zinc. Sesame oil extracted by cold pressing is not suitable for frying due to its low heat resistance, but it can be used in the formulation of salad dressings.
Javad Tavakoli; Mohammad Hossein Hadad Khodaparast; Reza Esmaeilzadeh kenari; Mahmoud Aminlari; Ali Sharif
Abstract
In this study, antioxidant activity of kolkhung skin oil, baneh skin oil and seasame oil were compared. The ratio between polyunsaturated to saturated fatty acids (PUFA/SFA) of kolkhung skin oil, bane skin oil and seasame seed oil were 0.52, 0.26 and 3.06, respectively. Total phenolic contents of kolkhung ...
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In this study, antioxidant activity of kolkhung skin oil, baneh skin oil and seasame oil were compared. The ratio between polyunsaturated to saturated fatty acids (PUFA/SFA) of kolkhung skin oil, bane skin oil and seasame seed oil were 0.52, 0.26 and 3.06, respectively. Total phenolic contents of kolkhung skin oil, bane skin oil and seasame seed oil were 99.67, 645.73 and 81.72 mg/kg, respectively. Total tocopherol content of kolkhung skin oil (2154.3mg/kg) was significantly higher than those of the other investigated oils, followed by seasame seed oil and bane skin oil ( 993.69 and 648.91 mg/kg, respectively). Antioxidant activity of the three mentioned oils were determined by DPPH, FRAP and rancimat tests. Antioxidant activity of kolkhung skin oil was significantly higher than those of the other investigated oils, followed seasame seed oil and bane skin oil, respectively. Also it was found a correlation between amount of antioxidant compounds of oils and their antioxidant activity.
