جستجوی مقالات مرتبط با کلیدواژه "antioxidant activity" در نشریات گروه "کشاورزی"

Due to climate situation of Iran, there is a high diversity of garden species such as Blackberries. Blackberry is one of the most important sources of anthocyanin, antioxidant, phenolic and flavonoid compounds. The present study was conducted to investigate the variation of phytochemicals and photosynthesis pigments traits in Iranian blackberry genotypes. For this purpose, four genotypes of R. sanctus were selected from the blackberry collections of the faculty of agriculture of Shiraz University and examined in a randomized complete block design in two-years. Then, at three different sampling dates (June (Khordad), August (Mordad) and October (Mehr)), the samples were harvested from both leaves and stem organs and transferred to laboratory. Finally, samples extracts used for measurement of traits including, IC50, flavonoid, total phenol, anthocyanin, flavanone, chlorophyll (a, b and total) and carotenoids. Based on the results, there was a significant variation between the studied individuals for IC50 (33.17-72.95 (leaf), 101.07-139.68 (stem), total phenol (117.77-172.17 (leaf), 79.16-138.79 (stems), flavonoid (275.79-389.76 (leaf), 100.03-151.44 (stem), flavanone (35.30-54.06 (leaf), 30.38-54.17 (stem), anthocyanin (50.33-73.34 (leaf), 35.34-48.25 (stem), along with other traits. The highest antioxidant activity (minimum IC50), phenol, Flavonoid, flavanone and anthocyanin were observed in August sampling date and both stem and leaf organ. According to correlation and regression analysis, there was a significant and positive correlation between the amount of antioxidant and phenolic compounds. Over all, with increasing the temperature especially in August, the IC50 was decreased, which it could be due to an increase of other phytochemical traits. So, the increase of phytochemical composition could be a criterion of tolerance to the harsh environmental condition such heat stress in August. In this regard, Babolsar were selected as bets genotype in terms of studied traits and tolerant genotype to heat stress as well.

Urtica dioica L., commonly known as nettle is a perennial herbaceous plant that is widely distributed throughout the world. This plant is rich in antioxidant compounds and possesses anti-inflammatory, anticancer, and antiallergic properties. Therefore, the aim of this study was to determine the bioactive compound groups, total phenolic content, total flavonoid content, and antioxidant activity of aqueous leaf extract of nettle plant. Fourier-transform infrared spectroscopy (FTIR) was used for identifying the bioactive compound groups. Additionally, the total phenolic content was measured using the Folin-Ciocalteu method, the total flavonoid content was determined by the aluminum chloride colorimetric method, and the antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. The results showed that the aqueous leaf extract of nettle contained 59.83 mg GAE/g of total phenols, 29.44 mg QE/g of total flavonoids, and exhibited antioxidant activity with 66.47% and 81.32% inhibition of DPPH and ABTS radicals, respectively. This study demonstrates that the aqueous leaf extract of nettle is a significant source of natural antioxidants and can be considered as a suitable alternative to synthetic antioxidants in food and pharmaceutical industries.

In recent years, the demand for healthy functional foods has increased and food industry is trying to meet these new needs. This study aimed to assess the effect of different concentrations of green tea powder (GTP) on the physicochemical characteristics, sensory properties, antioxidant activity, and culture viability of probiotic ice cream over a 90-day storage period. Seven ice cream samples containing 0–3% GTP and Lactobacillus casei were produced and evaluated at 0, 30, 60, and 90 days of storage. Folin-Ciocalteu and diphenyl picrylhydrazyl (DPPH) methods were applied to determine the total polyphenol content and antioxidant property, respectively. The results showed that the titratable acidity, antioxidant activity, total polyphenols, viscosity, melting resistance, and viable count of L. casei increased with increasing GTP concentration (p<0.05). Also over time, there was no significant difference in viscosity and total solids, but the total phenol, antioxidant activity, and viability of probiotic bacteria decreased significantly (p<0.05). The results of the sensory evaluation revealed that the flavor and color of the samples containing 1.5 and 2% GTP had the highest scores (p<0.05). Samples containing 1.5 % GTP that had the highest score of color, flavor, and overall acceptability, high antioxidant activity and viable count of L. casei ≥ 107 cfu/g during storage could be introduced as a new product with health-promoting properties.

The crucial role of food in life has prompted a shift towards products that not only offer good quality and nutritional properties but also ensure the overall health of consumers. Probiotics, which are non-pathogenic microorganisms, can restore intestinal microbial balance when consumed in sufficient quantities. In this study, Limosilactobacillus fermentum ARD2 isolated from local yogurt was investigated for its probiotic properties. Various aspects of this strain were evaluated, including acid resistance (at pH levels of 2, 3 and 4), resistance to bile salts (at concentrations of 0.3, 0.5 and 0.7 %), antimicrobial activity using disk diffusion agar and well diffusion agar methods, resistance to common therapeutic antibiotics, evaluation of antioxidant activity, cell surface hydrophobicity, DNase enzyme activity, hemolytic activity, and biogenic amine and cholesterol absorption. The results of the acid resistance tests indicated that the viability of L. fermentum ARD2 increased as pH levels rose from 2 to 4, with a decrease observed over time at a constant pH over 3 hours. Growth was inhibited with increasing concentrations of bile salts. Antimicrobial testing revealed that the acidic and neutralized cell-free supernatant (aCFS and nCFS) had no significant antimicrobial effect on Escherichia coli, while nCFS showed no antimicrobial effect on Shigella dysenteriae. L. fermentum ARD2 exhibited resistance to Ciprofloxacin and was semi-sensitive to Penicillin and Nitrofurazone. The L. fermentum ARD2 showed considerable antioxidant activity, with DPPH and ABTS free radical inhibition rates of 41.40% and 43.60%, respectively. Additionally, it demonstrated the ability to reduce cholesterol absorption by 38.60%. The strain tested negative for DNase and hemolytic activities, and biogenic amine production was not observed. Based on these findings, L. fermentum ARD2 exhibits promising probiotic characteristics and could be utilized as a probiotic bacterium in food products.

Vitis vinifera subsp. Sylvestris, belonging to vitis family and is one of the indigenous plants of Iran, was collected from Miankalleh. In this research, different plant extractions (methanol, water, chloroform, ethyl acetate) were obtained from the leaf and fruit of wild grapes. The yield of extraction was determined. Also, the total phenol and total flavonoid content of different extracts were analyzed and the antioxidant activity of the extracts was assessed using DPPH (2, 2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing power) methods. Our investigation showed that the aqueous extract of leaf (14.35%) and fruit (12.71%) had the highest level of extraction yield. The total phenolic content of the fruit was higher than the leaf. Also, the methanolic extract had a higher total phenolic content than other extracts in leaf (2.9±0.25 mg/g) and fruit (12.3±0.1 mg/g).Regarding the total flavonoid content, the methanolic extract of the fruit with 9.7±0. 03 mg/g, had the highest level. Investing the antioxidant activity using DPPH assay revealed that the aqueous leaf extract with IC50 of 26.74±0.12 µg/ml had the best result. The methanolic extract of the leaf was more potent than other extracts in the FRAP assay. In conclusion, the phytochemical analysis of the leaf and fruit of wild grapes showed that the methanolic extract had the best performance.

Canola oil with high unsaturated fatty acids and nutritional value is susceptible to oxidation due to lipid oxidation. Lipid oxidation leads to a reduction of nutritional quality, sensory and safety characteristics of the vegetable oils. To retard lipid oxidation, the synthetic antioxidants are usually used in the vegetable oils. By increasing the public concern about health problems of synthetic antioxidants, the use of natural antioxidants is increasing. Lavender (Lavandula officinalis) is an evergreen plant native to the Mediterranean. The presence of linalool, linalyl acetate, 1,8-cineole B-ocimene, terpinen-4-ol, and camphor in lavender essential oil, make it a good natural antioxidant which could use in food industry. Therefore, in the current research, it was aimed to investigate the antioxidant effect of lavender essential oil on the stability of canola oil.

The lavender was bought from Golestan province and dried in room temperature. The lavender essential oil was prepared by hydro distillation of flower heads. Then, the phenolic compounds were determined using GC-MASS. The Total phenolic content (TPC), flavonoid content (TFC), and antioxidant activity (FRAP and DPPH) of lavender essential oil were evaluated. Then, lavender essential oil in concentrations of 200, 400, 600, 800, and 1000 mg/kg was added to the crude canola oil compared to canola oils without antioxidants and synthetic antioxidant TBHQ (100 and 200 mg/kg). Then, the samples were kept at 60 to 70 oC for 12 days. The analysis was done in an interval of 24 h for 12 days. Lipid oxidation of samples was determined by peroxide value, p-anisidine value, TOTOX value, and thiobarbituric acid each 24 h. analyses of Data were done by one-way analysis of variance (ANOVA) using SPSS software and the means were compared by the Tukey multiple range test.

 According to the GC-MS analysis, 1, 8-cineole (59.45 %), linalool acetate (32.48 %), linalool (6.31 %), and limonene (1.06 %) were identified as the major constituent of lavender essential oil. Also, Total phenol, flavonoid, FRAP and DPPH (IC50) contents of lavender essential oil were 71.55 mg GAE/g, 82.66 mg of rutin/100 g, 12.63 mmol H2SO4, and 55.88 mg/ml, respectively. According to the results, all lipid oxidation indexes were increased after twelve days of storage. In general, lavender essential oil was effective in retarding the oxidation of canola oil at a temperature of 70 oC. Also, the concentration of 1000 mg/kg of the essential oil had antioxidant activities similar to the TBHQ in 100 mg/kg concentration.

 It was showed that lavender essential oil, as a natural antioxidant, has the ability to react with the radicals resulting from the oxidation of lipids and causes the interruption of oxidation chain reactions and increases the time and decreases the rate of oxidation. As observed, the oxidation of canola oil in all samples, especially the samples without antioxidants or antioxidants to a lesser extent, increased significantly with increasing storage time. In general, lavender essential oil at L1000 concentration and also in some oxidation indices of lavender essential oil at L800 concentration has an effective role in preventing the oxidation of canola oils like synthetic antioxidant TBHQ.

Postharvest fungal diseases can limit the storage period and shelf life, and thus market life of fruit and vegetables, which results in serious economic losses worldwide. Despite the efficacy of synthetic fungicides in the control of postharvest decay, public concerns about chemical and toxic residues in food and the increase in drug-resistant strains of many pathogens indicate the need for development of new strategies. Coatings and packaging materials have been considered as another method for increasing the postharvest storage time of fruits and vegetables. Chitosan-based nano composites are proper alternatives to mitigate the negative impacts of conventional coatings and films on human and environmental health. Additionally, natural chitosan coatings and packaging incorporated with functional compounds decrease the postharvest losses of fruits and vegetables without changing their nutritive and sensorial properties. Therefore, the current research work was performed to investigate the effectiveness of chitosan and chitosan nanofiber on the quality and storability of strawberry fruit cv. Paros. 

This study was conducted in the form of a factorial experiment based on a completely randomized design with two factors and three replications. The first factor was treatments in 5 levels including dry control, distilled water, chitosan 0.5%, chitosan nanofibers 0.2% and chitosan nanofibers 0.5% and the second factor was storage time in 5 levels including: Zero, 5, 10, 15 and 20 days. The treatments were applied as a 2-minute immersion of the fruits in the prepared solution at ambient temperature (25 ° C), and the samples were stored after drying in plastic disposable containers at 4°C and relative humidity of 85 to 90%. At the end of the storage periods, the values of weight loss, pH of fruit juice, total soluble solids, titratable acidity, and firmness of fruit tissue, color indexes, total anthocyanin, total phenol content, vitamin C content, antioxidant activity and percentage of decay of the aforementioned treatments were evaluated. 

The results showed that at the end of the storage period, the 0.5% chitosan nanofiber treatment was able to maintain the TA value 77% higher than the control at same-day. Also, the TSS of 0.5% and 0.2% chitosan nanofiber treatments was lower than the control, which indicates a delay in the tissue softening of coated fruits due to a lower breakdown of sugars. On the 20th day of storage, the pH, TSS/TA, and the percentage of weight loss in the treatment of 0.5% chitosan nanofiber were lower than the control; the explanation for the rise in pH of control fruits is due to the decrease in organic acids and potential sugar conversion. The highest value of firmness between treatments was found in the 0.5% chitosan nanofiber treatment (3.11 Newton) after 20 days of storage. The semi-permeable surface of coated fruits may have contributed to fruit firmness persistence by limiting metabolic gaseous exchange (oxygen and carbon dioxide) across the coating barrier, followed by a decrease in metabolic activity and oxidizing enzyme effectiveness. The highest content of vitamin C, total phenol, and total anthocyanin were in the 0.5% chitosan nanofiber treatment, which showed a significant difference from other treatments. At the end of storage, the percentage of antioxidant activity of fruits in coating treatments including 0.5% chitosan nanofiber, 0.2% chitosan nanofiber, and 0.5% chitosan, 25%, 14%, and 5%, respectively, was higher than the dry control. Higher contents of color indexes including Lightness (L*), Redness (a*), yellowness (b*) and Chroma, and lower values of Hugh angle were observed in fruit coated with chitosan nanofiber. The percentage of decay in chitosan nanofiber-treated fruits (0.5% and 0.2%) and chitosan (0.5%) decreased by 61%, 55%, and 43% more than the control, respectively.

The present study found that using a 0.5% chitosan nanofiber coating was the most effective way to maintain the quality of strawberries during storage for up to 20 days. It allowed good preservation quality such as weight loss, decay, antioxidant activity, firmness, color, Vitamin C, anthocyanin content, and total phenolic compounds. However, 20 days is a sensitive period for the commercialization of strawberries, considering the normal time of 7–14 days is generally accepted. Consequently, various storage strategies can be applied to suit the market needs.

Plant sprouts are receiving a great deal of attention because of their ‎abundance, bioavailability of components, and health benefits. Germinated legume seeds were the most ‎common sprouts consumed in the human diet. Alfalfa (Medicago sativa) sprout is a valuable source of ‎protein, fiber, minerals, vitamins (B vitamins), glucosinolate, and phenolic compounds. Alfalfa sprout is ‎usually consumed as dehydrated leaves, powder, or dietary supplements in the form of tablets. ‎Regarding nutritional values, alfalfa sprout powder (ASP) could act as a prebiotic agent. The present ‎study aimed to investigate the nutritional values and in vitro prebiotic potential of ASP on two probiotic ‎strains, namely Lactobacillus casei ATCC 393‎‏ ‏and Bifidobacterium longum ATCC 55813. Also, the ‎effects of fermentation of ASP by probiotics on polyphenolic content and antioxidant activity were ‎investigated. ‎

Fatty acid composition, amino acid profile, and mineral content of ASP were ‎determined using a gas chromatography-mass detector, amino acid analyzer, and inductively coupled ‎plasma-optical emission spectrometry, respectively. ASP at two concentration levels of 0.5 and 1% was ‎tested for its growth stimulation effect on two probiotics, L. casei and B. longum. Fructooligosaccharide ‎‎(FOS) and glucose were used as standard prebiotic and control positive, respectively. The changes in ‎probiotic populations and pH were monitored during 48 h fermentation in glucose-free MRS broth (GF-‎MRSB). The total phenolic content (TPC) and antioxidant activity of ASP were evaluated during ‎fermentation using the Folin–Ciocalteu method and the DPPH radical scavenging assay. ‎

ASP contains high levels of aspartic acid, glutamic acid, and essential amino acids, including ‎phenylalanine, leucine, and lysine. It also includes a high content of unsaturated fatty acids, including ‎linoleic and oleic acids. Potassium was found to be the mineral with the highest composition, followed ‎by phosphorus and calcium. Both probiotic strains could grow effectively in the presence of ASP. The ‎cell numbers of L. casei and B. longum increased by 4.91 and 5.11 Log CFU/ml after 48 h fermentation ‎of ASP-1%, which were comparable with the stimulatory effects of FOS and glucose. The pH decrease ‎of GF-MRSB was negatively‏ ‏correlated with the concentration of ASP. Antioxidant activity and TPC ‎increased continually during fermentation by both probiotics, with L. casei exhibiting a stronger impact. ‎

Results demonstrated that ASP is an excellent source of minerals, essential amino acids, ‎and unsaturated fatty acids. Probiotic bacteria not only survive in the presence of ASP but also increase ‎polyphenolic content, thus enhancing the antioxidant activity and functional capacity of the fermented ‎ASP. Fermenting phenolic compound-rich plant sprouts with probiotic bacteria can be considered a ‎novel approach to the development of functional foods.‎

Nowadays, there is a growing demand for artificial preservatives-free food products, due to the concerns about their adverse effects. In recent years, numerous studies have led to the identification of various natural compounds have the potential to be used as preservatives in variety of food products. For instance, plant metabolites, such as the essential oils of aromatic plants, possess antioxidant and antimicrobial properties. These attributes have led to their widespread use in various industries, particularly in the food industry. Mayonnaise is one of the most popular and widely used sauces in the world, applied to prepare a variety of foods, such as salads and sandwiches. Due to the absence of thermal processing and the use of chemical artificial preservatives in mayonnaise, it is advisable to consume it in moderation and with caution. The aim of this study was to investigate the possibility of using Mentha spicata L. essential oil in the formulation of mayonnaise as a natural antioxidant and its effects on some physicochemical and microbiological properties of mayonnaise.

Fresh M. spicata leaves were collected from the northern of Iran and dried. The essential oil was extracted by distillation with water using a Clevenger device, and its volatile components were identified and measured by gas chromatography-mass spectrometry (GC/MS). The total phenolic content of the essential oil was determined by the Folin-Ciocalteu method. In addition, the free radical scavenging activity of the essential oil was evaluated by DPPH and ABTS assays, using BHT as a synthetic antioxidant as a reference. The minimum inhibitory concentration (MIC) of the essential oil was assessed against Gram-positive (Bacillus cereus, Staphylococcus aureus and Listeria innocua) and Gram-negative (Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa) bacteria. M. spicata essential oil was added to the mayonnaise sauce in different concentrations (500, 1000, 2000 ppm) and its antioxidant activity was investigated under accelerated oxidation conditions (90°C temperature) for seven days. In current research, the peroxide, acid, and thiobarbituric acid values of mayonnaise samples containing concentrations of 500, 1000 and 2000 ppm of M. spicata essential oil were calculated. Then, they were compared with sauce samples containing concentrations of 100 and 200 ppm of BHT artificial preservative.

32 compounds were identified in the essential oil by GC-MS and the results showed that carvone (57.01%), d-limonene (16.79%), 1,8-cineole (7.56%) and beta-caryophyllene ( 2, 10%) were the main components of M. spicata essential oil. The total phenolic contents of the essential oil were found to be 0.246 mg of gallic acid per gram (dry weight). The tests performed for peroxide, acidity and thiobarbituric acid values showed that the use of high concentrations of the essential oil can be a favorable alternative to artificial antioxidants in mayonnaise. Additionally, the results of the antibacterial activity demonstrated that the diameter of the microbial growth inhibition zone of pathogenic Gram-positive Bacillus cereus and Staphylococcus aureus strains was greater than the Gram-negative strains of Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. However, among the pathogenic Gram-positive strains, Listeria innocua strain had the smallest microbial growth inhibition zone. Furthermore, the results of sensory evaluation showed that the essential oils concentrations of up to 1000 ppm had no significant effect on the sensory characteristics of mayonnaise.

Based on the findings of this study, it is possible to propose the use of M. spicata essential oil, known for its mild and pleasant aroma, as a natural antioxidant to prevent oil oxidation and extend the shelf life of mayonnaise.

This experiment was conducted in order to evaluate the effects of osmo-priming on the characteristics of germination, seedling and some physiological characteristics of two cultivars of rapeseed (Brassica napus L.) under saline conditions. The seeds of two spring rape varieties were pretreated with 29.5 mM potassium nitrate (KNO3) for 12 hours at 30 degrees Celsius. In the first experiment after priming, 25 primed and unprimed seeds were placed in petri dishes with 4 levels of salinity (0, 50, 100 and 150 mM of NaCl) in a completely randomized design in four replications. The results showed that the germination percentage of primed seeds was higher than non-primed seeds.In the second experiment, 20 primed and unprimed seeds were planted in pots filled with perlite and peat at a ratio of 3:1. The pots were kept for three weeks in the greenhouse with a temperature of 26/16 degrees Celsius . The pots were watered every day with saline solutions (0, 50, 100 and 150 mM of NaCl). The results of multi-way interaction also showed that, primed seeds had higher antioxidant enzyme activity and higher content of soluble sugars and proline, at the same time, cell membrane damage in them was lower due to lower concentration of malondialdehyde compared to non-primed seeds. Under salinity conditions of 150 mM, the highest dry weight, antioxidant activity, and accumulation of soluble sugars and lower concentration of malondialdehyde were observed in Hyola 401 variety. This research showed that priming with KNO3 improves canola seed germination under stress conditions.

In this study, anthocyanin and phenolic compounds were extracted from pomegranate peel powder with supercritical CO2 and Lepidium perfoliatumseed gum and maltodextrin were used as the nanoencapsulation wall. The nanoencapsulation extract was dried with a freeze dryer. Color stability and antioxidant activity of nanoencapsulation extract were evaluated. The levels of anthocyanin and phenolic compounds were evaluated by differential pH and Folin-Ciocalteu method, respectively. Particle size, nanoencapsulation efficiency of anthocyanin,nanoencapsulation phenol, color stabilityat different temperatures and pH as well as antioxidant activity were evaluated by DPPH. The amount of anthocyanin and phenol extracted in this method was 3.943±0.133 mg/g of pomegranate peel powder and 504.521±2.537 mg/g of gallic acid per 100 g, respectively. Nanoencapsulation efficiency was higher for anthocyanin than phenols. The release of anthocyanin at different pHs was different, so that anthocyanin behaved differently at different pHs. Polymerization and color increased with increasing temperature. The antioxidant activity of the fine-grained extract by DPPH method increased with increasing concentration and its IC50 was equivalent to 1.092± 0.024 m /ml.

Antioxidants, which are among the most active bioactive compounds in honey, play an important role in protecting living organisms against oxidative damage and prevent the occurrence of chronic diseases such as cancer, cardiovascular disease, and diabetes. Honey has a variety of enzymatic and non-enzymatic antioxidants, including glucose oxidase, catalase, L-ascorbic acid, flavonoids, phenolic acids, carotonoids and organic acids, amino acids and proteins. The antioxidant activity of honey is mainly due to the presence of valuable phenolic and flavonoid compounds in it, which inhibit free radicals produced in the oxidative reactions with various mechanisms. The amount of these compounds is influenced by various factors such as plant origin, season and environmental factors. Meanwhile, the herbal origin of honey has the greatest effect on its antioxidant activity. The use of honey to treat diseases has had a special place in medical science for a long time. Therefore, in this paper, the antioxidant properties of honey, its therapeutic and health-giving properties, especially in breast cancer is reviewed.

This study aimed to investigate the chemical composition, antioxidant properties, and antimicrobial activity of Tanacetum balsamita L. essential oil. The essential oil was extracted using the water distillation method, and then the total phenolic content (using the Folin-Ciocalteu method), total flavonoid content (using the aluminium chloride colorimetric method), antioxidant activity (using DPPH and ABTS free radical scavenging methods), and antimicrobial activity (using disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration methods) were evaluated. The total phenolic and flavonoid contents of the essential oil were found to be 29.50 mg gallic acid equivalent per gram and 14.90 mg quercetin equivalent per gram, respectively. The essential oil exhibited significant antioxidant activity, with the ability to scavenge 50.40% and 53.55% of free radicals DPPH and ABTS, respectively. According to the results of disc diffusion agar method, Bacillus subtilis and Salmonella typhi were the most sensitive and resistant bacterial strains, respectively, with zone of inhibition diameters of 16 mm and 10.50 mm. The zone of inhibition diameters for these bacteria in the well diffusion agar method were obtained as 16.30 mm and 10.80 mm, respectively. The minimum inhibitory concentration and minimum bactericidal concentration for B. subtilis were determined as 4 mg/mL and 32 mg/mL, respectively, and for S. typhi, they were 64 mg/mL and greater than 512 mg/mL, respectively. According to the results, T. balsamita essential oil can be used as a natural antioxidant and antimicrobial agent in food products.