Showing 411 results for Antioxidant
Volume 0, Issue 0 (1-2024)
Abstract
Polycyclic aromatic hydrocarbons (PAHs), a class of organic pollutants, have been observed to exert deleterious effects on plant growth and various physiological processes. In this study, the effect of different concentrations of phenanthrene (0, 25, 50, 75, and 100 ppm) on growth parameters, photosynthetic pigments, some antioxidant enzymes, and some biochemical compounds of the maize plant were investigated. The experiments were conducted as pot cultures of plants under controlled conditions using a completely randomized design (CRD) with three replications for each treatment. Increasing phenanthrene concentration reduced all studied growth parameters and significantly increased photosynthetic pigment contents. Phenanthrene led to the increase in catalase, peroxidase, and superoxide dismutase activities in the roots but in shoots, only the peroxidase activity was increased. Moreover, higher phenanthrene concentrations were associated with elevated levels of malondialdehyde and hydrogen peroxide, coupled with a marked reduction in soluble sugar content in both shoot and root tissues (p<0.05). Also, increase in phenanthrene concentration in the shoots decreased the total phenol and flavonoid contents compared to anthocyanin. Phenanthrene treatment led to a significant reduction in the concentrations of lauric acid, meric acid, palmitic acid, and oleic acid in maize shoots. In conclusion, it seems that high concentrations of phenanthrene induce oxidative stress in the maize, and plants improve their enzymatic antioxidant system to moderate the stress condition. In addition, damage of cell membranes by phenanthrene leads to weakening of plants root system as well as disordering in water and nutrient uptake and finally reduction in the plant growth.
Volume 0, Issue 0 (1-2024)
Abstract
Mexican limes have a limited shelf life due to color changes and reduced freshness. This study evaluated the effects of melatonin (ML) and pomegranate seed oil (PSO) on maintaining postharvest quality at 20 ± 2°C and 50-60% relative humidity. The results showed that melatonin at 100 µM+PSO and 200 µM+PSO exhibited the highest overall fruit acceptability. The control group displayed the most weight loss (20.8%), while PSO demonstrated the least (12.5%). With the exception of the PSO treatment, all other treatments exhibited significantly elevated levels of phenols, flavonoids, and antioxidants. The PSO and control treatments demonstrated the lowest catalase (69 U/g FW) and peroxidase (53.5 U/g FW) activities, while the highest polyphenol oxidase activity (99.6 U/g FW) was also observed in these groups. The control and PSO treatments also exhibited the highest total soluble solids (TSS) content (8.2%) and the lowest acidity (8.5%). Overall, most traits exhibited significant differences between the treatment groups and the control, excluding the PSO treatment.
Keywords Citrus, Postharvest quality, Shelf life, Antioxidant.
Volume 0, Issue 0 (1-2024)
Abstract
The global popularity of tea is due to its unique taste and health benefits, which are highly linked with its nutrient and antioxidant activity (AOA). However, diverse growing habitats, including distinct altitudes and soil edaphic factors, may regulate foliar nutrition and AOA of tea. Thus, this study aimed to (1) compare the nutritional characteristics and AOA of clonal tea grown in lowland and highland plantations and (2) investigate the influence of soil edaphic factors on tea foliar nutrition and AOA. Tea leaves and soils of fourteen tea clones were sampled between October 2021 to March 2022 from lowland and highland plantations in Peninsular Malaysia. Leaves were analysed for nutritional content and antioxidant activity, while soil samples underwent physical and nutritional analysis. Results showed significant variations in most foliar nutrients, except for Ca in the lowlands and Fe in the highlands. While the highland-grown tea exhibited higher nutrient concentration, lowland-grown tea demonstrated superior AOA. AT53 and 1248 were identified as promising among the clones, characterized by the highest nutrients and AOA levels, respectively. Soil nutrient availability significantly influenced foliar nutrient uptake, while soil pH was associated with the AOA. These findings highlight the critical role of soil edaphic factors in shaping tea quality, providing valuable insight for tea growers to optimize soil management strategies and maintain tea yield and quality in the future. We found that soil nutrients have a significant association with nutrient uptake, while soil pH is associated with the agronomic characteristics of tea. Investigating the association between ecological variables and tea foliar properties (nutrients and AOA) is of great importance for tea growers as they develop strategies to maintain the yield and quality of tea in the future.
Volume 0, Issue 0 (1-2024)
Abstract
Due to their antimicrobial and antioxidant properties, essential oils are used as natural preservatives. The purpose of this study was to investigate the chemical composition, antioxidant properties, and antimicrobial activity of emulsion and nanoemulsion forms of Salvia officinalis, Pimpinella anisum, Dracocephalum moldavica, and Syzygium aromaticum essential oils. The Agar well-diffusion assay results obtained from the experiment suggested that nanoemulsion of Dracocephalum moldavica essential oil had the maximum antimicrobial activity against the pathogenic microorganisms drawn in the experiment. The inhibition zone diameters of the nanoemulsion of this essential oil against Shigella dysenteriae, Salmonella Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Bacillus cereus were 11.03, 11.82, 13.02, 13.13, 13.13, 13.62, and 14.10 mm, respectively. In contrast, the inhibition zone diameters of the emulsion form of this essential oil against S. dysenteriae, S. Typhimurium, P. aeruginosa, S. aureus, L. monocytogenes, E. coli, and B. cereus were 9.66, 10.34, 10.84, 11.84, 11.34, 11.17, and 11.24 mm, respectively. The major components of Dracocephalum moldavica essential oil included geraniol (27.24%), geranial (10.75%), alpha-copaene (8.16%), alpha-pinene (7.37%), carvacrol (7.41%), limonene (6.86%), and nerol (6.45%). The nanoemulsion form of the essential oils investigated thus possessed a significantly greater antioxidant potential compared to their emulsion form. This study also demonstrated that the nanoemulsions exhibited significantly lower IC50 values compared to the emulsions. From the results, it was seen that the nanoemulsion form of Dracocephalum moldavica essential oil had the lowest IC50 and EC50 values of 22.17 µg/ml and 4.51 µg/ml, respectively.
Zienab Noori Hashem Abad, Seyed Hamid Hosseinipour, Seyed Mahdi Ojagh,
Volume 2, Issue 3 (12-2013)
Abstract
The effect of the antioxidant extracts on the quality indices of rainbow trout fillet stored at refrigerator (4±1ºC) for 15 days was investigated. The fillets in 3 treatments, including salted in 10% brine, salted in 10% brine plus 1% nettle leaf extract, and salted in 10% brine plus synthetic antioxidant BHT were evaluated at every 3 days interval, using the quality indices including the free fatty acids (FFA), thiobarbituric acid (TBA), peroxide (PV), moisture content, pH levels and sensory characteristics. The results showed that TBA and FFA values increased significantly (p<0/05), but PV significantly decreased in all treatments during the course of storage (p<0/05). Samples containing antioxidants had significantly lower TBA, PV and FFA values in comparison with the control sample throughout the storage. Also, the methanol extract from nettle leaves (at 1% balance) controlled the TBA, PV and FFA indices and entirely replaced the synthetic BHT antioxidants (at 1% balance). Since the sensory evaluation (smell, texture, taste and after taste elements) showed no significant differences between the two antioxidants, both are recommended to preserve the quality of rainbow trout fillet. The nettle leaf extract was found to be more efficient on shelf life extension the fillet.
Volume 2, Issue 7 (12-2005)
Abstract
A group of the natural antioxidants is the polyphenols in green tea leave extracts (GTE). In this research, the extraction of antioxidants from the leaves was done with aqueous solution and then the extract was purified and finally dried and made into powder. Then the antioxidant effects of produced powder and α -tocopherol at 200 and 500 ppm , butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) at 100 and 200 ppm , and the combination synergistic effect of mixtures: 200 ppm GTE+500 ppm α -tocopherol , 500 ppm GTE+200 ppm BHA and 500 ppm GTE+200 ppm BHT in two types of sunflower oil (with and without citric acid as a chelator) at 50oC and time intervals of 0, 5, 8, 12 days were examined and compared for peroxide value (PV) and thiobarbituric acid (TBA) test. Results showed that the individually antioxidant effect of GTE at both concentrations was better than that of other antioxidants. Combination of GTE+BHT demonstrated antagonistic effect but no remarkable synergism or antagonisim was observed in other combinations.
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Volume 3, Issue 2 (9-2014)
Abstract
The aim of the present study was to evaluate the effects of enriched Artemia with fish and soybean oils supplemented with vitamin E on growth performance, stress resistance, antioxidant enzymes activity and lipid peroxidation of Persian sturgeon (Acipenser persicus) larvae. Five experimental diets including non-enriched Artemia (control diet), Artemia enriched with soybean oil supplemented with 15 or 30% vitamin E (S15 and S30 diets) and fish oil supplemented with 15 or 30% vitamin E (F15 and F30 diets) were used. The larvae were fed to apparent satiation for 17 days. The results indicated that fish fed enriched Artemia had no significant differences compared with control group in terms of growth and survival, but increase in vitamin E levels from 15 to 30 % improved growth performance and resistance to salinity stress. Vitamin E content in fish fed S15 and S30 diets was significantly higher compared with the other treatments. Antioxidant enzymes activity in fish fed non-enriched Artemia, F15 and F30 diets were higher. The highest TBA value was observed in fish fed non-enriched Artemia. The results demonstrated that the addition of vitamin E to the fish and soybean oils for Artemia enrichment could reduce oxidation of oils and beneficial for the health and quality of larvae. In conclusion, enrichment of Artemia with soybean oil supplemented with 30 % vitamin E (S30 diet) is recommended for feeding Persian sturgeon larvae.
Volume 4, Issue 2 (6-2016)
Abstract
The antibacterial and antioxidant activities of methanol and acetone extracts of three marine algae, including Hypnea hamulosa, Gracilaria corticata and Enteromorpha intestinalis wereinvestigated.Antioxidant activities were determined by means of total antioxidant capacity, total phenolic compounds, DPPH radical scavenging activity and ferric reducing antioxidant power. Antibacterial activity was determined using a paper disc diffusion method against pathogenic bacteria, including Listeria monocytogenes, Escherichia coli and Bacillus subtilis. Acetone extract of E. intestinalis showed the highest antioxidant activity and contained the highest phenolic compounds. The highest percentage of DPPH radical scavenging activity was observed in the methanol extract of H. hamulosa (p<0.05). The highest ferric reducing antioxidant power was observed in the methanol extract of Glacilaria (p<0.05). The strongest inhibition (p<0.05) against L. monocytogenes was shown by the methanol extract of E. intestinalis and the highest inhibition against B. subtilis and E. coli was observed in the acetone extract (p<0.05). In conclusion, E. intestinalis extracts showed favorable antioxidant and antibacterial activity suggesting its application in food and pharmacological industries.
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Volume 5, Issue 1 (6-2016)
Abstract
Solvent extraction and taguchi method were used to optimize conditions for the antioxidant activity of Azolla fern extracts. The independent processing variables were ethanol concentration, extraction time and solid to solvent ratio. Ethanol concentration and solvent to solid ratio significantly affected antioxidant activity measured by the total phenol content (p < 0.05). whereas the extraction time did not significantly affect the activity (p > 0.05). Antioxidant activity of the extracts, determined by the total phenolic content, varied from 5.77 to 16.42 mg acid gallic equivalents/g of dry sample. DPPH scavenging activity percentage ranged from %20.51 to %93.71. Ethanol concentration of %50 and sample to solvent ratio of 1 to 15 were optimal for the highest antioxidant activities measured by the TPC assay and the DPPH method. The optimal extraction time was 48h. The result show that azolla fern is suitable for antioxidant extraction.
Leila Ramezanzadeh, , Maryam Nikkhah,
Volume 5, Issue 2 (9-2016)
Abstract
In this study, gelatin was first extracted by alkaline and acidic treatment including 0.19 N NaOH and 0.12 N acetic acid solution by ratio of skin of rainbow trout (Oncorhynchus mykiss (to solution of 1 to 7 and then heat treatment in 50 °C. Then, hydrolysed by alcalase enzyme for 4 hours with the ratio of enzyme to the substrate 1 to 100 and the degree of hydrolysis were measured after 4 hours. DPPH and ABTS free radical scavenging activity, as well as reducing power assay of gelatin hydrolysate were measured. The results showed that the degree of hydrolysis after 4 hours was 46/7%. Also the highest DPPH and ABTS free radical scavenging and reducing power at concentration of 10 mg/ml were 39/8%, 50/7%, and 0/123, respectively. The skin from fish filleting can be a suitable raw material for extraction of peptides with biological activities. The results showed that peptides derived from rainbow trout fish skin gelatin can be considered as a natural antioxidant.
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Volume 5, Issue 2 (9-2016)
Abstract
In this study the effect of edible coating containing pomegranate peel extract (PPE) on the quality and shelf life of silver carp (Hypophthalmichthysmolitrix)fillet was investigated during refrigerated storage at 4 Cº. The total phenolic content (262.5 mg tannic acid/g sample) and DPPH free radical scavenging activity (87%) of PPE using methanol as solvent were determined. The mixture of edible coating was prepared (60% cool water + 30% wheat flour + 10% corn flour). Freshly fish fillet were assigned to three treatments: control (fillet without PPE); fillet treated with 5% PPE (T1) and 10% PPE (T2). Chemical (pH, and thiobarbituric acid (TBA)) and microbiological (total viable count (TVC) and psychrotrophic count (PTC)) analysis were used to evaluated the effect of PPE during refrigerated storage. The results show that addition of PPE considerably delayed lipid oxidation in silver carp fillet in T1 and T2 compared with control samples. According to microbiological assay, T1 and T2 samples on 12th of storage reached to maximum acceptability limit (7 log10 CFU/g) while it was happened on 9th of storage for control samples.
Mohammad Reza Soleimani, , Maryam Nikkhah,
Volume 5, Issue 3 (12-2016)
Abstract
Fish protein hydrolysates from whole kilka, using alcalase enzyme (ratio 1: 100) under optimal temperature (55°C) and pH (8.5) was evaluated for its hydrolysis degree and antioxidant activity. Results of the hydrolysis degree recorded at time intervals of 1, 2, 3 and 4 hours indicated the hydrolysis degree increased with increase in the hydrolysis time. The evaluation of FPH antioxidant activity, using DPPH, ABTS and reducing power assay tests at 3 concentrations (1, 2 and 5 mg/ml indicated the highest inhibitory effect at 5 mg/ml was 74.4%, 72.3% and 1.8 absorbance in 700 nm for DPPH, ABTS and reducing power assay, respectively. Generally, the findings of this research confirmed the potential of kilka as a source of natural antioxidants for food applications.
Mehdi Tabarsa, , ,
Volume 5, Issue 4 (3-2017)
Abstract
Effect of different temperature (30 to 90 °C), time (10 to 70 min) and pH (4 to 9) conditions were investigated on the extraction efficiency of polysaccharides from seaweed E. intestinalis. Results showed that the extraction temperature had the highest effect on the enhancement of polysaccharide content. The highest polysaccharide extraction yield was achieved at 90 °C, 30 min and pH 8. Therefore, antioxidant effects of polysaccharides obtained at temperatures 30, 70 and 90 °C, times 10, 30 and 50 min, and pH 4, 7 and 8 with significant yield differences were evaluated. DPPH radical scavenging activity, ferric reducing power and total antioxidant activity were employed in order to evaluate the antioxidant properties of polysaccharides. The maximum DPPH radical scavenging activity was obtained for polysaccharides of 30 °C (73.90%), 30 min (95.08%) and pH 7 (75.61%). The highest reducing power was achieved for polysaccharides of 70 °C (97.49%), 50 min (99.05%) and pH 8 (97.49%). The maximum total antioxidant activity was obtained for polysaccharides of 70 °C (49.97), 10 min (62.32) and pH 7 (59.11 mg ascorbic acid/ g dried seaweed powder?). Overall, findings of current study suggest that the polysaccharides from green seaweed E. intestinalis possess antioxidant capacity and that the use of high temperature, long time and acidic or basic pH in extraction process results in diminishing this antioxidant capacity.
Volume 5, Issue 18 (10-2008)
Abstract
In this experiment, acetone was used to extract the phenolic compounds of grape pomace by colorimetric method (Folin-Ciocalteu). The phenolics extract levels of 50, 150, 250 and 350 ppm were used to assess their antioxidant activity in raw soybean oil. On day 0, 4, 8 and 12 the proxide value for soybean oil was estimated. Also, the TBA value for soybean oil on day 0, 5, 9 and 13 was estimated. The results showed that the phenolic compounds whose content in grape pomace is 64 g/kg DM has an antioxidant activity. The level of 150 ppm of tannin extract from grape pomace showed a desirable activity to prevent the oxidation of raw soybean oil. The antioxidant activity of this level was higher than those obtained by the level 200 ppm from synthetic antioxidants. Therefore, the use of phenolic compound in grape pomace as natural antioxidants can be recommended.
Volume 6, Issue 1 (1-2004)
Abstract
In this research, methanolic extraction of Salvia leriifolia leaves produced a higher yield and antioxidative activity than other organic solvents (ethanol, acetone, chloroform, n-hexane). The methanolic extract was reserved about 24 hours in the refrigerator and its precipitates were then separated. The extract was separated into 12 fractions by thin-layer chromatography (TLC). The highest yields were found in fractions with Rf values of 0.29, 0.54, 0.11 and 0.38 at 16.24%, 12.48%, 8.81% and 7.60%, respectively. All fractions and also whole methanolic extract and precipitates of methanolic extract had more anti-oxidative activity than the control based on the thiocyanate method. Whole methanolic ex-tract, precipitates of methanolic extract and most separated fractions showed more anti-oxidative activity than –tocopherol. The fraction with Rf value of 0.29 at 16.24% yield and 85.61% antioxidative activity of synthetic antioxidant BHT based on thiocyanat method was chosen as the fraction with the highest yield and the highest antioxidative ac-tivity.
Masoumeh Amouzad Khalili, Abdolmohammad Abedian Kenari, Masoud Rezaei,
Volume 6, Issue 1 (6-2017)
Abstract
The effect of vitamins C and E in enhancing the shelf life of the algal paste during 12 weeks cold storage (4°C) was assessed. The microalga, Nannochloropsis oculata, was grown in Conway media under 24ºC temperature, 25ppt salinity, and continuous light intensity of 1000- 2000 lux with) and harvested at the logarithmic phase by cream separator centrifugation at 12000 rpm in the form of paste. The algal cell viability was determined by Evans blue dye. The algal paste samples were treated with different vitamin treatments, including: vitamin C and E (0.1%w/w), and an equal proportions of mixed vitamin E and C, and then stored in refrigerator for two months. The results showed that the 95% cell viability of vitamin C treated paste was significantly higher than the control group (p>0.05). FFA and pH in vitamin C treated group was lower than the control treatment. The comparsion of between different treatments during the storage period indicating that it contains vit E had a slower increase than the other treatments in during the storage the time. Overall, it was demonstrated that vitamins functioned as suitable preservatives for the microalgal paste in cold storage (4 °C).
Volume 6, Issue 2 (11-2015)
Abstract
Free radicals, having one or more unpaired electrons in the outer orbit, which are oxygen-centred free radicals, sometimes known as reactive oxygen species (ROS). The oxidative stress imposed by ROS plays an important role in many chronic and degenerative diseases. The aim of the present research was undertaken to study the antioxidant activity and polyphenolic content in the different extracts of sea urchin Echinometra mathaei. Different extracts (spine, shell, gonad and aristotol lantern) of sea urchin were isolated by three solvents (n- hexan, ethyl acetate, methanol). Antioxidant activity of extracts was assessed by measured reducing power, DPPH free radical scavenging activity and total antioxidant capacity assays, and compared with the synthetic antioxidant butylated hydroxytoluent (BHT) and Ascorbic acid. Total phenolic and flavonoid contents were measured spectrophotometrically. According to the results of the study, highest the reducing power and free radical-scavenging activity of the methanolic shell and methanolic spine, respectively. In total antioxidant capacity assay, the antioxidant activity of aristotol lantern ethyl acetate, spine and gonad n-hexan was higher as compared to that of the ascorbic acid. The highest total phenol and flavonoid compound content per gram of the methanolic spine were 0.0044±0.0003 mg gallic acid equivalents and 24.616±0.7167 mg quercetin equivalents, respectively. Significant differences were observed at P
Mehdi Tabarsa, Niloofar Jokar Borazjani, Masoud Rezaei,
Volume 6, Issue 2 (9-2017)
Abstract
The extraction of hydrocolloids from seaweeds is associated with production of secondary metabolites during pretreatment step. In this study, the antioxidant properties were evaluated for secondary metabolites from brown seaweed S. angustifolium. The crude extract obtained by 80% ethanol for four hours and then partitioned using hexane, chloroform, ethyl acetate and water. The extraction yield was found to be 4% for crude extract and varied between 2.8-43% for fractions. The evaluation of antioxidant properties revealed a successful solvent fractionation in portioning antioxidant compounds. Among various fractions, ethyl acetate exhibited the highest activity in DPPH radical scavenging (75.78%), ABTS radical scavenging (88.92%), reducing power (67.54%) and total antioxidant (0.34 Abs) capacities. The highest amount of phenolic contents was found in ethyl acetate fraction (277.86 mg/ TA in extract) while the lowest amount was in aqueous fraction (21.36 mg/ TA in extract). The highest correlation (R2 = 0.88) was observed between total phenolic content and total antioxidant activity. Overall, the results of current study show that ethanol extract of S. angustifolium contains major bioactive compounds suggesting its potential application in food industry as a natural antioxidant.
Volume 6, Issue 3 (2-2004)
Abstract
Water stress is a serious environmental problem throughout the world. It is a conse-quence of both drought and salinity which may be relieved by breeding cultivars that can tolerate low soil water potentials. Alfalfa (Medicago sativa L.) is normally grown in arid and semi-arid zones. One approach to improving the ability of the crop tolerate drought is to make use of the variation provided by tissue culture derived from somaclonal varia-tion. Seedlings of a moderately salt tolerant line CUF 101-1S derived from the commercial variety CUF 101 were used as a source of explants to initiate and regenerate tissue cul-tures. Regenerant plantlets were allowed to grow to maturity, selfed, and set seed. These seeds (R1) were germinated and grown in a nutrient medium containing 0, 200 and 250 g l-1 polyethylene glycol (PEG) 6000 and additional calcium as CaCl2 (4.0 mol m-3) for 14 days to assess their ability to withstand stress in the progeny generation. Tolerance to PEG was assessed using measurements of root and shoot lengths. Proline levels and activ-ity of the antioxidant enzymes, catalase (EC 1.11.1.6) and glutathione reductase (GR) (EC 1.6.4.2) were also determined. Selected somaclones were more tolerant than the parent. A large increase in the level of proline was observed in the somaclones compared with the parent variety in response to PEG stress. The activity of catalase and glutathione reduc-tase increased in the tolerant genotypes but remained unchanged in the parent when they were subjected to PEG stress.
Volume 6, Issue 3 (9-2017)
Abstract
Trichoderma is one of the efficient biocontrol agents due to its high reproductive capacity, ability to survive under unfavorable conditions, efficiency in nutrient utilization, capacity to modify the rhizosphere, strong aggregativeness against the pathogenic fungi and efficiency in promoting plant growth and defense mechanisms. Therefore, the present investigation is carried out as an alternative practical and safe approach for mass multiplication of Trichoderma on different agro based media. Among them wheat straw and farmyard manure were found to be the best solid media supplemented with 10% wheat flour.The highest population count of Trichoderma species was observed in wheat straw. Antioxidant producing crops were also added to this carrier medium at a rate of 5g/kg in order to enhance the shelf life of propagules of Trichoderma species. Maximum population count wasobserved in soybean, maize and brown rice.