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Background and Objectives: Citrus peel, a by-product of fruit juice industry, is a source of natural antioxidants. The search for natural antioxidants for use in food technology, cosmetics, and pharmaceutical science has become a major industrial and scientific research challenge in recent decades. The objective of this study was to determine the antioxidant activity of the inner sour orange peel (mesocarp) extract, the antioxidant stability of the extract by the ferric reducing antioxidant power (FRAP) method, and its protective effect on lipid oxidation in raw and cooked fish by the thiobarbituric acid reactant substances test (TBARS) technique. Materials and Methods: An ethanol extract of the inner sour orange peel (mesocarp) was prepared. Samples of the aqueous solution of the extract were then stored for 1 month under different conditions (light, room temperature,, dark room temperature, refrigerator, and freezer). The antioxidant activity and stability of the samples were measured by the FRAP assay and their short- (90 minutes) and long-term (14 days) protection effect on lipid oxidation was evaluated using the TBARS test. Results: The initial FRAP value of the 0.1% aqueous solution of the extract at room temperature (570 µM) decreased by 14% after one month (p=0.007). The change in the FRAP value of a 0.005% aqueous solution of vitamin C under the same conditions was a 77% decrease (p=0.000) from an initial value of 541 µM. The data also showed that the TBARS value of the raw fish samples containing no extract increased from 1.32µM to 3.173 µM after 14 days, while in presence of a 5% aqueous solution of the extract the increase was from 0.92 µM to 1.09 µM (p<0.05). Under the same conditions, the increases in the TBARS value of the cooked fish samples were also significant─from an initial value of 2.28 µM to 5.85 µM (p=0.000) and from 1.77µM to 3.11 µM (p=0.000) in the absence and in the presence of a 5% aqueous solution of extract, respectively. Conclusion: The results show that sour orange mesocarp extract has antioxidant activity with high stability during storage and a protective effect on lipid oxidation. Keywords : Antioxidant , Lipid oxidation , FRAP assay , TBARS , Sour orange peel, Fish

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Background and Objective: An effective way to prevent oxidation of oils and fats is addition of antioxidants. However, the use of synthetic antioxidants for this purpose is gradually being discontinued due to their undesirable side effects. Therefore, extraction and production of natural antioxidants is a necessity. The objective of this study was to isolate cinnamon extract by the Soxhlet and cold solvent methods, employing acetone and methanol as solvents, and to investigate its effects on the stability of sunflower oil. Materials and Methods: Acetone and methanolic extracts of cinnamon were obtained by the Soxhlet and cold solvent methods. Extraction efficiency was determined and the total content of phenolic compounds in the extracts measured by the Folin Ciocalteau method. The extracts were added to refined sunflower oil samples at concentrations of 0.02%, 0.04%, 0.06%, 0.08% and 0.1%, followed by determination of stability of the samples (as assessed by delayed oxidation). Peroxide value and induction period measurements were used to evaluate the antioxidant activity, the control being synthetic antioxidant TBHQ at a concentration of 0.01%. Results: The extraction efficiency by the Soxhlet method was higher than that of the cold solvent method however the phenolic compounds content of the extracts isolated by the cold solvent method was higher. In both the Soxhlet and cold solvent methods, the efficiency of exrtarction by methanol was higher than by acetone solvent, while the phenolic compounds content was higher when acetone solvent was used. The data also showed that the antioxidant activity of the extracts was concentration-dependent .The extract isolated with acetone acted better than that isolated with methanol, such that at a concentration of 0.1% it showed the highest activity, second only to synthetic antioxidant TBHQ at the same concentration. Conclusion: Cinnamon extract has antioxidant activity, which is related to its content of phenolic compounds and other antioxidants. Further research is required to get more information before it can be used routinely as a source of natural antioxidants. Keywords: Oxidation, Antioxidant, Cinnamon extract, Phenolic compounds, Sunflower oil

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Background and Objectives: Common antioxidants in the food industry are usually synthetic compounds, some with proven toxic and carcinogenic natures. The present study examined the effect of tocopherol on oil oxidation in mayonnaise at room temperature over its 6 mo shelf life and compared its performance with common synthetic antioxidants. Materials and Methods: The treatments were the natural and synthetic antioxidants of 450 ppm tocopherol (MTC) and 150 ppm TBHQ (MTQ) added to plain oil, which was then used to produce mayonnaise. The quality of the products was evaluated by measuring the acidity, peroxide and anisidine values, hexanal concentration, and by sensory evaluation. Results: The results showed that the oil phase in both samples oxidized during the 6 mo shelf life. The acid value, which indicates hydrolytic rancidity, increased for both treatments, but showed no significant difference between treatments over time. The change in peroxide levels in MTC was much less than in MTQ. Tocopherol limited hydroperoxide formation effectively however, in the last month, the peroxide value for MTC was more than for MTQ. Anisidine value and hexanal concentration are the secondary products of oxidation and showed no significant differences between two treatments. Sensory scores for the two treatments decreased similarly over the course of the shelf life. These results indicate that tocopherol produced no flavor interaction with other compounds in emulsion and showed no adverse effects on sensory characteristics. Conclusions: It can be concluded overall that tocopherol as a natural antioxidant was able to control oil phase oxidation in mayonnaise effectively and can be good substitute for TBHQ in mayonnaise. Keywords: Tocopherol, TBHQ, Mayonnaise, Oxidation

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Background and Objectives: Edible films and coatings are effective method for decreasing oxidation and increasing the shelf life of pistachios. The present study investigated the effect of an edible gelatin coating containing ascorbic acid (AA: 1% w/v) and propyl gallate (PG: 100 ppm) on the oxidative stability and sensory properties of roasted pistachio nuts. Materials and Methods: Pistachios were subjected to one of five treatment formulations: uncoated, AA + PG, gelatin + PG, gelatin + AA, gelatin +AA+ PG. The pistachio samples were roasted, packaged, and stored in triplicate at 35°C and 50°C. Chemical analysis was measurement of free fatty acid (FFA), peroxide content (meq.O2 kg-1), anisidin content, and totox. Sensory evaluation (texture, rancidity, taste, overall acceptability) was performed by 20 semi-trained panelists over 3 mo of storage. Results: The edible gelatin coating containing antioxidant agents, especially AA, showed a statistically significant decrease (p < 0.05) in the rate of oxidation. Incorporation of two antioxidant agents had no synergistic effect on the antioxidant properties of the gelatin coating however, samples coated with gelatin containing AA + PG exhibited the greatest increase in shelf life. In addition, high temperatures during storage decreased the quality of the pistachio oil and total acceptability of the product. Edible gelatin-antioxidant coating did not affect the total acceptability of the product, but protected against lipid oxidation during storage. The use of gelatin coating increased the firmness of the pistachio nuts. Conclusion: Edible gelatin coating containing antioxidant agents show good potential for decreasing the rate of oxidation and increasing the shelf life of pistachio nuts. Keywords: Antioxidant, Oxidation, Pistachio, Edible gelatin coatings, Sensory properties

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Background and Objectives: One way to protect the oil against oxidation is using antioxidants. Since the most used synthetic antioxidants are harmful to health, due to safety concerns, there is an increasing trend among food scientists to replace synthetic antioxidants with natural ones, which, in general, are supposed to be safer. Walnut hulls, due to having high antioxidant effects, is a good choice as a natural antioxidant. The aim of this study, is investigation of the antioxidant effects of the extract and powder of green walnut hall on the oxidation of sunflower oil. Materials & Methods: Green walnut hull extract was prepared with Maceration and Soxhlet extraction methods and the amount of phenolic compounds and antioxidant activity, respectively, was determined by Folin-Ciocalteu and DPPH radical trap methods. Antioxidant effects of different concentrations (100, 250, 500 and 1000 mg/kg) of green hull extract and powder (500 and 1000 mg/kg) were compared with the control and artificial antioxidant TBHQ in the maximum limit amount (200 mg/kg) through evaluation of acidity, peroxide value and thiobarbituric (TBA) on days 0, 5, 10 and 15 days of storage at 70°C. Results: The amount of total phenolics and flavonoids for Maceration method was 17.81 and 1.59 and for Soxhlet method was 98.07 and 38.7, respectively, on the basis of gallic acid and catechin (mg/g sample) for phenols and flavonoids obtained. The walnut hulls’ EC50 was 0.15 mg/ml. The data showed that peroxide value and thiobarbituric oxidation rate increase over time, but the samples containing extract and powder of walnut hulls compared to the control in most concentrations showed less oxidation. The use of high concentrations of green walnut hull extract increased oil oxidation, and the best result was obtained for 100 mg/kg that could well slow the oxidation process and compete with TBHQ at 200 mg/kg. Conclusion: Soxhlet extraction method leads to higher levels of polyphenols than the Maceration method. Less concentration of green hull extract is more effective than higher concentrations in reducing oxidation. Green walnut hull is presented as a source of high antioxidant effect with low price to replace with synthetic antioxidants. Keywords: Oxidation, Sunflower oil, Natural antioxidant, Green walnut hull extract

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Background and Objectives: Nowadays, natural antioxidants are used to replace synthetic antioxidants for delaying or preventing the oxidation of edible oils. In this study, microalgae Spirulina (Arthrospira platensis), as natural antioxidant, was added to virgin olive oil for improving its oxidative stability.

Materials and Methods: In the first stage, the antioxidant activity of Spirulina and the physico-chemical properties of virgin olive oil were evaluated. In the second stage, the effect of Spirulina addition on the oxidative stability of virgin olive oil was determined using active oxygen method (AOM). Three samples of virgin olive oil with 0.5% (w/w) Spirulina (as natural antioxidant), 0.01% (w/w) BHT (as synthetic antioxidant), and without any antioxidant (as control) were prepared. The mean of induction period, protection factor, and antioxidant activity were calculated. Statistical analysis was performed using SPSS 19 software.

Results: The results showed that Spirulina has good total phenolic content (67.72 mg gallic acid eq/g sample), total flavonoid content (9.16 mg quercetin eq/g sample), IC₅₀ value (0.364 mg/ml), and total antioxidant activity (17.98 mg Vit C/g sample). Induction period, protection factor, and antioxidant activity of the sample containing Spirulina (31.15 h, 1.37, and 0.42, respectively) were significantly higher than those of the control sample (22.85 h, 1, and 0.00, respectively) and less than those of the sample containing BHT (42.71 h, 1.87, and 1.00, respectively).

Conclusions: Due to the banned use of synthetic antioxidants in virgin olive oil and appropriate antioxidant activity of Spirulina, Spirulina as natural antioxidant can improve the oxidative stability of virgin olive oil.

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Background and Objectives: Gamma ray has been shown as an effective method to reducing or eliminating microbial contamination of raw and cooked meat products. However, irradiation-induced chemical and sensory changes are important to accept the technology for both the meat industry and consumers. The objective of this study was to determine the effect of gamma-irradiation (0, 2, 4, 6 and 8 kGy) on the fatty acid and lipid oxidation of German sausage during refrigerated storage (4 ^oC).

Materials and Methods: German sausage samples were irradiated at 2, 4, 6 and 8 kGy doses. During the storage period at 4 ^oC, TBA value and fatty acid profiles were considered.

Results: The TBA value was significantly increased by irradiation at 6 and 8 kGy. Also irradiation at 6 and 8 kGy caused significant decrease of oleic acid and linoleic acid and significant increase of total trans fatty acids in both of these products.

Conclusion:  Irradiation at 2 and 4 kGy doses is suggested as the best dose. However, more research in the subject seems necessary.

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Background and Objectives: Iran is considered as one of the most important suppliers of date all over the word. Since date is a rich source of polyphenolic compounds, the aim of this study is to investigation of the antioxidant and antifungal properties of dates pulp and its methanolic extract.
Materials & Methods: Methanolic extract of date pulp was extracted by Soxhlet and evaluated by colorimetric method. In addition, antioxidant properties of the extracts were measured by DPPH radical scavenging method. The effect of different levels of date extract and pulp on acidic, peroxide and thiobarbituric acid values of sunflower oil during 15 days of storage at 70 °C were investigated. Antifungal effect of date extract and pulp against Aspergillus niger was evaluated according to the disc diffusion method.
Results: Total phenolic (mg gallic acid/ 100 g sample) and flavonoid (mg catechin/100 g sample) compounds of extract and pulp were 414.72, 304.18, 28.62 and 20.72, respectively. DPPH radical scavenging activity of TBHQ, date pulp and extract showed the results as follows: TBHQ ˃ date extract ˃date pulp. Based on the results, addition of date pulp and its extract decreased peroxide and TBA values of sunflower oil compared to the control sample. The results of antifungal test indicated antifungal effects of date extract against Aspergillus niger.
Conclusion: According to the obtained results, date pulp and its extract can be introduced as a cost-effective source of antioxidant as well as antifungal compound in food technology. 
 

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Background and Objectives: Exercise is a good stimulating factor for decrease of blood lipid. Lemon (Citrus limon L.) essential oil with antioxidant properties can prevent oxidative stresses. The present study was carried out to assess effects of four-week consumption of lemon essential oil with swimming training on lipid profile and lipid peroxidation.
 Materials & Methods: Totally, 40 male mice (40 gr ±5) were divided randomly into four major groups (n = 10), including control, swimming, lemon essential oil and swimming with lemon essential oil groups. Swimming practice included four weeks of swimming in 25–27 ºC water for 30 min in each session, five sessions in a week. Lemon essential oil (50 mg/kg) was administered using gavage. Lipid peroxidation and lipid profile were assessed by blood sampling from the animal heart.
Results: Lemon essential oil significantly decreased triglycerides (p < 0.001), LDL-C (p < 0.01), VLDL-C (p < 0.01), cholesterol (p < 0.01) and MDA (p < 0.001). Swimming training significantly decreased triglycerides, LDL-C, VLDL-C and MDA; however, cholesterol and HDL-C did not change significantly. Lemon essential oil consumption with swimming training significantly decreased triglycerides (p < 0.001), LDL-C (p < 0.01), VLDL-C (p < 0.01) and MDA (p < 0.001) and increased HDL-C (p < 0.05).
Conclusion: In general, lime essential oil consumption with swimming training include decreasing effects on lipid peroxidation and lipid profile.

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Background and Objectives: Doxorubicin-increased oxidative stress destroys tumors and normal cells, especially in heart tissues. The objective of the present study was to investigate effects of eight weeks of aerobic training and crocin consumption on doxorubicin induced heart tissue oxidative stress in male rats.
 Materials & Methods: In this experimental study, 50 male rats were randomly divided into five major groups of control, doxorubicin, doxorubicin with training, doxorubicin with crocin and doxorubicin with a combination of training and crocin. Doxorubicin was intraperitoneally injected at 2 mg/kg BW for seven weeks. The crocin treated groups orally received 10 mg/kg BW, five times per week for eight weeks. Aerobic training included 60 min of treadmill running with 40–60 of maximum speed, five times per week for eight weeks. Malondialdehyde levels and catalase and superoxide dismutase activities were assessed in heart tissues. The ANOVA test was used to compare groups with each other. The significant level was considered at p ≤ 0.05.
Results: Doxorubicin injection significantly increased malondialdehyde levels (p = 0.0001) and decreased catalase (p = 0.0001) and superoxide dismutase (p = 0.0001) activities in heart tissues. The eight weeks aerobic training, crocin consumption and combination of the two interventions decreased malondialdehyde levels (p = 0.0001) and increased catalase (p = 0.0001) and superoxide dismutase activities (p = 0.0001) in heart tissues of doxorubicin receivers.
Conclusion: Aerobic training and crocin consumption alone and in combination can decrease doxorubicin induced oxidative stress and improve internal antioxidant defense in doxorubicin receivers.

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