Showing 6 results for Antioxidant
E. Khosravi, Sh. Dokhani, G. H. Kabir,
Volume 9, Issue 3 (10-2005)
Abstract
The meat productions are the most popular among different food products. On of the serious problems of this kind of products may be the change of the physical and chemical properties. The Restriction of the use of synthetic antioxidants have prompted the extensive research on the effect of the natural antioxidant and replacement of synthetic antioxidant with the natural ones. In this study, the effect of α-tochopherol (vitamin E) and propyl gallate on German sausage was evaluated. Four different German sausages were formulated and prepared in 30 Kg batches as follows: control without antioxidant, sausages plus α- tochopherol (200 or 500 ppm) and sausages plus propyl gallate (200 ppm). Twelve Kg of the samples were filled into cellulosic casings and the other 18 Kg in polyamidic casings. All samples were cooked. One third of the packed samples were stored at (4˚C ± 1) for 10 days and the rest were stored at (– 18 ˚C ± 1) for 6 months. The extent of autoxidation for samples were determind by peroxid and TBA values. During the storage period, autoxidation rates of control samples were more than other treatments. Propyl gallate was more effective in reduction of autoxidation than α- tochopherol treatments. Addition of 500 ppm vitamin E was more effective than 200 ppm. Significant differences were observed among treatments (P< 0.05). The study of the shear strength of the stored susages at the (4 ºC ±1) for the 10 days indicated that the most shear strength is seen in the cellulosic casing samples. The same results obtained for the stored samples at the (-18 ºC ±1) for the 6 months.
S Bazi, M Haydari, N Mehdinejad, F Abasi,
Volume 12, Issue 46 (1-2009)
Abstract
To evaluate effects of different salinity levels on activity of antioxidant enzymes (CAT, APX and GPX) and osmotic components (carbohydrate and proline) in two sorghum genotypes, an experiment was conducted as completely randomized factorial design with three replications in Zabol university in 2007. Three levels of salinity control (0), 100 and 200 mM NaCl and two sorghum genotypes (Payam and Sistan) were compared. Results showed that by increasing salinity levels from 0 to 200 mM NaCl, the activities of these three antioxidant enzymes were significantly increased and the highest level of activity was observed in 200 mM salinity. Payam cultivar had the highest level of APX and GPX enzyme activity in these experiments. salinity significantly changed two osmotic adjustment concentrations (Carbohydrate and proline) and increased their concentrations. The highest proline and carbohydrate were showN in Sistan and Payam, respectively. In this study we found positive correlation between osmotic components and antioxidant enzyme activity. The results showed that in these two sorghum cultivars the two mechanisms help with salinity tolerance. A direct relationship between activity of the antioxidant- enzymes and accumulation of osmotic regulators (carbohydrate and proline) was observed. In Payam genotype, as the activity of the enzymes and accumulation of osmotic regulators increased, the weight of the plants decreased. The decrease in weight could mean some of plant energy is allocated to the production of antioxidant enzymes and osmotic regulators.
Z Amini, R Hadad, F Moradi,
Volume 12, Issue 46 (1-2009)
Abstract
The effects of irrigation, dry farming and drought treatments on the activities of antioxidant enzymes including superoxide dismutase, ascorbate peroxidase, catalase and peroxidase in barley leaves at different generative growth stages under field conditions were investigated. Three senescence parameters including chlorophyll, total soluble protein and rubisco large subunit protein loss, were also studied in order to compare our results to those reported by other researchers. The results showed that leaf relative water content (RWC), chlorophyll and total soluble protein and rubisco large subunit protein content declined with leaf age and the effect of water deficit. The activity of superoxide dismutase declined with the progress of the leaf age on all treatments but ascorbate peroxidase activity declined with leaf age only in irrigated (control) plants. There were no significant differences among developmental stages in catalase activity in control plants, while catalase activity declined in the water dry farming and drought stress conditions. Peroxidase activity increased with the progress of senescence for all of treatments in such conditions. Water deficit stress triggered increases in antioxidant enzymes activities. Results showed that among all studied enzymes, peroxidase has a key role in increasing resistance to oxidative stress on both the senescence stages and drought stress condition in Hordeum vulgare.
A Dolatabadian, A Modares Sanavi, M Sharifi,
Volume 13, Issue 47 (4-2009)
Abstract
In order to study the effects of salt stress and leaf feeding by ascorbic acid on antioxidant enzyme activity, proline accumulation and lipid peroxidation on leaves and roots of Brassica napus L. cvs. Okapi, an experiment was conducted as a factorial in a completely random design with three replications. Plants were exposed to salt stresses by NaCl solution (200 mM) and foliar were treated by ascorbic acid solution (25mM). Catalase, Superoxide dismutase and peroxidase activity were assayed in shoot and root. Also, malondialdehyde content and proline and chlorophyll in leaves were determined. The results showed that the activity of all antioxidant enzymes (except for SOD in roots) were increased significantly in plants under salt stress, and ascorbic acid application, as a antioxidant decreased their activity in leaves, but in roots it was not effective. Total protein content in leaves and roots decreased significantly under salinity condition. Ascorbic acid treatment increased total protein content under salt stress in both roots and shoots. Measurement of malondialdehyde content in leaves and roots showed that lipid peroxidation was increased by active oxygen species due to salt stress, and ascorbic acid reduced lipid peroxidation only in leaves. Chlorophyll content was also decreased by salinity compared to control. According to the result of present study, ascorbic acid application decreases deleterious effect of salinity.
A Shaker Ardekani, M Shahedi, G Kabir,
Volume 13, Issue 47 (4-2009)
Abstract
Pistachio processing, such as production of pistachio butter, is one of the ways to increase the added value of pistachio. Pistachio butter is a paste containing mainly milled, roasted pistachio kernel and sugar. In this investigation, the effect of two emulsifiers (lecithin and mono-di glycerids) at three levels of 0.0, 1.0, 2.0%, on the oil leakage and the effects of BHT as an antioxidant at three levels of 0.00, 0.01 and 0.02% on the peroxide values of pistachio butter and paste after 4 months storage at 20 °C were studied. Each experiment was performed in triplicates. Rheological and organoleptic tests were performed on the finished products. The results were statistically analyzed by a completely randomized Design and by making comparisons between the means via multiple range Duncan's test (P <0.05). Roasting of the pistachios at 110°C for 15 min was the best condition as determined by taste panelists. Moreover, addition of 15-25% of sugar in butter formula, received the best score by the panelists. The results of organoleptic tests showed that the sample containing lecithin and mono-diglycerides had the least leakage of oil. Based on the results, pistachio butter produced in this investigation received higher score in terms of flavor and texture than industrial pistachio butter in the market. Results also showed that addition of BHT had a significant effect on shelf life of pistachio butter. Rheological experiments showed that pistachio butter produced in this investigation was 1.5 times softer than its industrial counterpart. The results indicated that the best formula for production of pistachio butter was 72.99 - 82.99 % roasted pistachio kernels, 15-25 % sugar, 1% lecithin, 1% mono di glyceride and 0.01 % BHT.
S Yazdanpanah, P Arjmand, H Porazarang, M Mohanadi Jafari,
Volume 13, Issue 47 (4-2009)
Abstract
Antioxidant activity of pomegranate (Punica granatum) peel extract (PPE), extracted by either methanol or ethanol solvent, was studied by phosphomolybdenum method. Antioxidant activity of methanolic PPE was higher than the other. To evaluate heat stability of PPE in sunflower oil, the rancidity rate of the oil was compared at 90, 120, and 150ºC with those containing α-tocopherol and synthetic BHT, using rancimat method. A sample including 1000 ppm PPE had the highest induction period at 90,120 ,150ºC. The use of PPE had no adverse effect on sensory characteristics of potato chips as judged by the taste panel.
