In order to study the net effects of unsaturation of lipid system and temperature on antioxidant activity in this research, used triacyleglycerols from fish, canola and olive oil (without other antioxidant and proxidant) with difference degree of unsaturation at temperature 60-100 in presence concentration 0, 0.01% and 0.02% TBHQ. Increased the portion of mono-unsaturated fatty acid than polyunsaturated fatty acid from fish, canola and olive (1.87, 2.28 and 5.78, respectively) caused to decreased oxidation rate in absence of TBHQ (15.24, 7.23 and 0.006 meq g-1 h-1, in 60). Increased the temperature caused to rise proxide accumulation in all lipid systems, the highest increased related to olive, then fish triacylglycerol from 60 to 80. The hishest and lowest effectiveness and activity of TBHQ observed in 0.02% at 60 (44.47, 46521.52) and 0.01% at 100 (6.86, 201.84) in canola and fish, respectively. The results showed that increased temperature from 60 to 80 in fish oil (high degree of polyunsaturation system) rise about more than 2 fold proxide accumulation than other systems and temperatures. In addition the results showed that effects of degree of unstauration system and temperature have considerable effect on activity of antioxidant.

On of the most important factors which causes fresh and heated sausages to be deteriorated is their fat oxidation. In this study three types of synthetic antioxidants including butylated hydroxi anysol (BHA), butylated hydroxi toluene (BHT), and tertiary butyl hydroquinone (TBHQ) were used in order to prevent oxidative deterioration. The Tested meat products included four types of sausages which different concentration of these antioxidants were added to their pulpy products. The results of adding the antioxidants in stability of the products fat and their shelf life were determined through Oxygen Bomb Test (OBT) and Oven Storage Test (OST). Finally it was suggested that the heated samples of sausage using both BHA and TBHQ amounted 0.06% as well as fresh products using only 0.01% BHA, had the longest and the shortest shelf life against oxidation and keeping duration, respectively. This study was carried out during 2007-2008 in Oily Seeds Cultivation Co, Tehran.

In this study antioxidant and antiradical activity of Bahar narang extract in corn oil irradiated with UV rays (30 min) in comparison to TBHQ were investigated. Measurement of phenolic compounds in extract showed it had a 65±1.5 mg /g phenolic compounds, thereby Bahar narang extract had a good IC50=73±2.1mg/mg for inactivation of DPPH radicals. Antioxidant activity of Bahar narang extract in corn oil irradiated with UV rays in comparison to TBHQ indicated the UV rays induced oxidation process in corn oil samples both with and without additives. This effect was more vigorous (more peroxide, conjugated diene and anisidine value) when irradiation was carried out prior to addition of the additives. Bahar narang extract also decreased deterioration of polyunsaturated fatty acids in corn oil during oxidation. The findings show the good potential of Bahar narang extract when it is used as a natural antioxidant in food lipids.

Introduction: The aim of this study is to investigate the type and amount of phenolic compounds in orange peel essential oil as a source of natural antioxidant and its effect on the oxidative stability of soybean oil. Materials and Methods: The compounds in orange peel essential oil were determined using GC / MS. The antioxidant activity was evaluated by the method of iron regeneration test and DPPH and then the essential oil in four different concentrations (2%, 5%, 10% and 20%) and the synthetic antioxidant TBHQ in the permissible range (0. 01%) were added to soybean oil. Finally, the peroxide and thiobarbituric acid and conjugate diene values were determined. Results: D-Limonene was the predominant compound in orange peel essential oil. One gram of essential oil of orange peel contains 0. 16 mg phenolic compounds based on dry galic acid. According to DPPH and regenerative power, orange peel essential oil showed antioxidant activity, although it was less active than TBHQ. Based on the oven test results as the concentration of essential oil is increased, higher antioxidant activity was observed. There was no significant difference between 5% and 10% concentrations based on the statistical tests, but with an increase in concentration up to 20%, the essential oil was acting as prooxidant (P <0. 05). The result indicated that essential oil had the highest antioxidant activity at 5% concentration. Conclusion: The result indicated that the essential oil of orange peel had stabilising effect on soybean oil during thermal conditions as compared to control sample (P <0. 05). Therefore, it might be employed as a natural antioxidant in foods, particularly those containing edible oils.

Background: The present study was designed to investigate the chronic effects of diazinon on oxidative stress markers in brain and heart of rats and the possible protective effects of tert butyl hydroquinone (TBHQ), as an antioxidant.Objectives: Therefore, the present study was undertaken to evaluate the protective role of TBHQ on oxidative stress induced by diazinon in brain and heart tissues of rats after 7 weeks exposure to sub-lethal dose of diazinon.Materials and Methods: In this experimental study, 28 male Wistar rats which were randomly divided into four groups: diazinon group (10 mg/kg, once a day), TBHQ group (0.028 g/kg of diet, once a day), diazinon + TBHQ group (diazinon, 10 mg/kg, once a day +TBHQ, 0.028 g/kg of diet, once a day) and control group (corn oil, as vehicle of diazinon and TBHQ). The animals were treated with diazinon, TBHQ or corn oil orally using a stomach tube for 7 weeks.Results: At the end of 7th week, total thiol groups, ferric reducing antioxidant power (FRAP) and malondialdehyde (MDA) levels in brain and heart tissues were investigated. A significant increase in MDA levels (P = 0.01) in heart tissue was evident in diazinon group, when compared to control group. Rats of the TBHQ and diazinon + TBHQ groups presented a significant increase in thiol groups (P = 0.01), when compared to control and diazinon groups. In addition, TBHQ administration significantly increased the FRAP level of brain tissue in TBHQ and TBHQ + diazinon groups, when compared with control and diazinon groups, respectively (P= 0.001).Conclusions: The results of the present study showed that TBHQ treatment could improve antioxidant status in brain and heart tissues of rats with chronic toxicity of diazinon. However, it could not ameliorate the lipid peroxidation sufficiently.