Antioxidant Activity Of Vegetables Research Articles

Chemical composition, minerals concentration, total phenolic compounds, flavonoids content and antioxidant capacity in organic and conventional vegetables

The demand for organic vegetables is increasing worldwide, which has led to the growth of organic agriculture. However, information on chemical composition and antioxidant activity in vegetables grown organically under controlled conditions remains uncertain. For this study, 3 vegetables widely consumed in Brazil were cultivated in controlled organic and conventional cultivation systems: lettuce, coriander and tomato. Their chemical composition, mineral concentration, phenolic compound content, flavonoids and antioxidant activity (AA) were evaluated. The analyses of chemical and mineral composition revealed differences between the cultivation systems. Organic lettuce presented higher content of ashes, calcium and potassium. A higher content of phenolic compounds and flavonoids was observed in most organic vegetables. Using the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) assay, the organic tomato exhibited higher AA compared to conventional, while the ferric-reducing antioxidant power (FRAP) method showed higher AA for organic coriander and tomato than theirs conventional version. The correlation between bioactive compounds and AA was positive, higher and stronger for organic vegetables, considering phenolic compounds (including flavonoids) and DPPH or FRAP antioxidant activity. Principal Component Analysis (PCA) disclosed that organic lettuce and coriander were grouped according bioactive components. In general, organic vegetables showed better results for bioactive compounds and antioxidant activity.

Effects of Preharvest Methyl Jasmonate and Salicylic Acid Treatments on Growth, Quality, Volatile Components, and Antioxidant Systems of Chinese Chives.

Methyl jasmonate (MeJA) and salicylic acid (SA) regulate the production of biologically active compounds in plants and stimulate the accumulation of plant aromatic substances. However, the underlying mechanisms of how MeJA and SA influence characteristic flavor compounds and the antioxidant activity of vegetables are poorly understood. Five MeJA and SA concentrations were used to investigate the dose-dependent effects of these phytohormones on the dry and fresh weight; chlorophyll abundance; the contents of vitamin C, soluble protein, and sugar, nitrate, total phenols, flavonoids, volatile components, and enzymatically produced pyruvic acid; and antioxidant activity in Chinese chive. We found that MeJA and SA at concentrations of 500 and 150 μM, respectively, significantly increased the levels of total chlorophyll, phenols and flavonoids, vitamin C, and volatile components and significantly reduced the accumulation of nitrate. In addition, compared with the control, 500 μM of MeJA significantly increased the soluble sugar and protein content, and 150 μM SA significantly increased the dry and fresh weight of Chinese chive. Furthermore, these concentrations of MeJA and SA significantly increased the enzymatic pyruvate content and the amount of sulfide and aromatic volatile compounds and improved the characteristic flavor compounds. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, Trolox-equivalent antioxidant capacity, and ferric-reducing antioxidant capacity were significantly improved after a preharvest treatment with 500 μM MeJA and 150 μM SA, which could improve the antioxidant activity, thus improving the postharvest quality and preservation characteristics of Chinese chives. Taken together, a preharvest treatment with 500 μM MeJA and 150 μM SA is optimal to improve the growth, quality, antioxidant activity, and flavor of Chinese chive, thereby enhancing its commercial value.

Review of the antioxidant properties of wild edible plants in Ethiopia

This work aims to study the potential and importance of wild edible plants (WEPs) as antioxidants in treating different diseases caused by free radicals. A total of 67 species belonging to 50 genera under 36 families and naturally growing in Ethiopia were recorded after assessing all available documents. About 16.2% of the total (413) WEPs were recorded in the country. The plant families with more number of species known to have antioxidants are Amaranthaceae and Moraceae 7 species each. Fruits are the dominant edible parts followed by leaves. Compounds such as tannins, oxalates and phenolic acids are the major contributors to the antioxidant activity of vegetables, fruits and medicinal plants. Plants also have many phytochemicals which are a potential source of natural antioxidants such as phenolic diterpenes, flavonoids, flavonols, alkaloids, iridoids and saponins, High consumption of fruits and vegetables is associated with a lowered occurrence of cancer, heart disease, inflammation, arthritis, neurodegenerative diseases and diabetes. Antioxidant components including vitamin C, vitamin E, carotenoid, and plant polyphenols appeared to play a key role in reducing the development of such diseases. This review gives a general overview of the antioxidant properties of different parts of WEPs in a single volume and ease selection of the best species for further research. The chemical composition, antioxidant contents and energy values of wild plants consumed by Ethiopians indicated that they provide key nutrients such as carbohydrates minerals and vitamins. The plants will be lost along with their valuable nutrients and indigenous knowledge without proper management and conservation in the right places and habitats. Keywords: antioxidant, Ethiopia, health benefit, phytochemicals, wild edible plants.

Antioxidant, total phenols and proximate constituents of four tropical leafy vegetables

Vegetables are the cheapest and readily available sources of vitamins and mineral for most tropical African diets. The aim of this study was to determine the bioactive and proximate characteristics of four (4) indigenous Ghanaian leafy vegetables namely Solanum macrocarpon (Gboma), Talinum fruticosum (Ademe), Corchorus olitorius (Yevogboma) and Amaranthus spp. (Atormaa). Proximate analysis was done according to methods described by AOAC. Total phenolic content (TPC) was determined by the Folin–Ciocalteu method whereas total flavonoid content was determined by aluminum chloride technique. The antioxidant activities of the vegetables were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, 2,2-azinobis,3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay and the Ferric reducing ability of plasma (FRAP) assay. The carbohydrate content of the vegetables studied was the major (59.22%–73.56%) constituent and the least was fat (0.08%–2.65%). The total phenolic and flavonoids content ranged from 0.10 µg GA/g to 9.81 µg GA/g and 363.5 mg QE/g to 1296 mg QE/g respectively. Antioxidant activities of the different vegetables ranged from 1.4% to 70.3% for DPPH activity, ABTS (83%–93%) and FRAP (0.356–0.242). The studied leafy vegetables are good sources of proteins, carbohydrates, fibers and had appreciable ash content and antioxidant activities. Consumption of these leafy vegetables, would help fight degenerative diseases and also improve food and nutrition security.

Enhanced Antioxidant Activity in Mung Bean Seedlings Grown under Slow Clinorotation

Initial growth studies in space have demonstrated microgravity has the potential to enhance antioxidant activity in fruit and vegetables. To examine whether a slow-rotating clinostat here on Earth can produce functional foods with enhanced antioxidant activity and related compounds, including carotenoids, phenolics and ascorbic acid, we grew mung bean seedlings under clinorotation (2 rpm) and measured the above components. The clinostat seedlings had higher antioxidant activity and accumulation of related compounds, compared to seedlings grown under normal gravity. To further explore the causes for these results, α-amylase activity and amount of starch in cotyledons were measured. Higher α-amylase activity and lower starch levels were observed in the cotyledons under clinorotation, suggesting the higher levels of sugars resulting from starch conversion were promoting the synthesis of antioxidant compounds and higher antioxidant activity in seedlings when grown under clinorotation. Our data indicate that a clinostat can enhance antioxidant activity in vegetables in the early developmental stage.

Alterations in phenolic compound levels and antioxidant activity in response to cooking technique effects: A meta-analytic investigation

ABSTRACTThe aim of this study was to review prior studies that have evaluated the effects of cooking techniques on polyphenol levels and antioxidant activity in vegetables and to release a meta-analysis of the findings. Meta-analysis with a random effect model was conducted using the weighted response ratios (R*) that were calculated for each experiment. Baking (R* = 0.51), blanching (R* = 0.94), boiling (R* = 0.62), microwaving (R* = 0.54) and pressure cooking (R* = 0.47) techniques precipitated significant reductions in the polyphenol levels. Significant decreases in the antioxidant activity levels were noted after baking (R* = 0.45) and boiling (R* = 0.76), while significant increases were observed after frying (R* = 2.26) and steaming (R* = 1.52).

Determination of Phenolic Compounds and Antioxidant Activity in Vegetables Consumed in Mekelle Tigray Ethiopia

Vegetables are widely consumed in Mekelle and imported from different regions and zones of the countries. This study was performed to evaluate the phenolic content and antioxidant activity of vegetables commonly consumed in Mekelle. Kale, carrot, cabbage and barcoli were used in the study. This research studies in detail the contents of phenolic compounds determined by the Folin−Ciocalteu reagent and the antioxidant activities determined by DPPH (using diphenyl-p-picrylhydrazyl radical). Among all vegetables kale showed highest phenolic content followed by barcoli, cabbage and carrot and the highest antioxidant activity were barcoli followed by kale, cabbage and carrot which was expressed in % of DPPH consumption after 30 minutes of reaction. The data shows the importance of antioxidant activity of vegetables in the diet.

Determination of Antioxidant Activity of Selected Vegetables Grown in Iran under Reversed Phase Conditions with UPLC

This study describes the determination of some phenolic compounds in four different vegetables of Kerman in Iran including Carrots, Celery, Lettuce and red cabbage .The phenolic compounds analyzed were (Ascorbate, Ferulic acid, Naringin) using reverse phase high performance liquid chromatography (RPUPLC). The results of analysis showed in vegetables ranged between 90 and 1080mg /kg. A high and significant correlation between antioxidant activity and total phenolic content was determined in vegetables (r2 = 0.9461 P < 0.06). However, flavonoid content was not significantly correlated with antioxidant activity in vegetables. It was observed that total phenolic content is the major contributor to the antioxidant activity of vegetables.DOI: http://dx.doi.org/10.3126/ijls.v9i5.12712

Phenolics, Flavonoids and Antioxidant Activity of Vegetables as Thai Side Dish

The total phenolics, flavonoids and antioxidant activity of 21 selected kinds of Thai side dish vegetables were determined. The result showed that all kinds of Thai side dish vegetables contained phenolic and flavonoid compounds. The Thai side dish vegetables that contained the highest phenolic compound was Pak bung tai muang, 1.66±0.006 mgGAE/g. As Ma khua puang and Kra jeab kheaw contained the highest flavonoid compound (0.14±0.001 mgRE/g). In the part of antioxidant activity, Kha-on displayed the highest antioxidant activity with 91.99±1.36%inhibit by DPPH assay and 1.65±0.03mM FeSO4 by FRAP assay method. Although this result revealed that Thai side dish vegetables may not high source of phenoloic and flavonoid compounds, they showed high efficiency of antioxidation power. It was suggested that Thai side dish vegetables would become new good source and natural of phenolic and flavonoid compounds because Thai people generally ate most of all vegetables as side dish in fresh cut and scald so phenolics and flavonoids were not destroyed from cooking process. In addition, they usually consumed Thai side dish fresh cut vegetables at least 100 gram/time/person which were benefit for the human health.

Changes in the antioxidant activities of vegetables as a consequence of interactions between active compounds

The biological activities of in vitro bioaccessible and bioavailable compounds of tomato, onion, garlic, and lettuce and their interactions in commonly consumed combinations were studied. The bioaccessibility of phenolic compounds (ACP), the potential bioavailability (AVP), the antioxidant bioaccessibility (BAC), the bioavailability (BAV), the bioefficiency (BEF), and the interaction (IF) factors were determined. It was found that antiradical compounds were bioaccessible. Furthermore, antiradical compounds from tomato/garlic acted synergistically (IF=0.42), whereas in other cases additive interactions were observed. BAC values of catalase activators averaged at about 1.50; however, owing to their potential bioavailability (BAV above 5.56) they possessed high bioefficiency (BEF about 9). On the other hand, all vegetables that contained bioavailable and bioefficient lipoxygenase inhibitors acted antagonistically. Xanthine oxidase (XO) inhibitors were found to be bioavailable (BAV from 2.61 to 3.98) and bioefficient (BEF from 2.87 to 5.50) and strong synergistic interactions between them were also determined.

Flavonoid content and antioxidant activity of vegetables from Indonesia

Extracts from 11 vegetables of Indonesian origin were screened for flavonoid content, total phenolics, and antioxidant activity. The flavonols myricetin, quercetin, and kaempferol and flavones luteolin and apigenin were quantified by HPLC. Flavonoid content in mg/100 g fresh weight (fw) was apparently initially reported for Cosmos caudatus H.B.K. (52.19), Polyscias pinnata (52.19), Pluchea indica Less. (6.39), Nothopanax scutellarius (Burm.f.) Merr (5.43), Talinum triangulare (Jacq.) Willd. (3.93), Pilea melastomoides (Poir.) Bl. (2.27), and Etlingera elatior (Jack) R.M.Sm (1.18). The flavonoid content of the vegetables studied were mainly quercetin and kaempferol and ranged from 0.3 to 143 mg/100 g fw, with the highest level found in Sauropus androgynus (L) Merr. C. caudatus H.B.K. had the greatest total phenols among the vegetables analysed, with 1.52 mg GAE/100 g fw. P. indica Less. and C. caudatus H.B.K. had the highest antioxidant activity as measured by ferric cyanide reducing power, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) scavenging, and inhibition of linoleic acid oxidation. Therefore, S. androgynus (L) Merr, C. caudatus H.B.K., and P. pinnata were identified as potentially rich sources of dietary flavonoids and antioxidants.

Influence of Cooking Methods on Antioxidant Activity of Vegetables

The influence of home cooking methods (boiling, microwaving, pressure-cooking, griddling, frying, and baking) on the antioxidant activity of vegetables has been evaluated in 20 vegetables, using different antioxidant activity assays (lipoperoxyl and hydroxyl radicals scavenging and TEAC). Artichoke was the only vegetable that kept its very high scavenging-lipoperoxyl radical capacity in all the cooking methods. The highest losses of LOO. scavenging capacity were observed in cauliflower after boiling and microwaving, pea after boiling, and zucchini after boiling and frying. Beetroot, green bean, and garlic kept their antioxidant activity after most cooking treatments. Swiss chard and pepper lost OH. scavenging capacity in all the processes. Celery increased its antioxidant capacity in all the cooking methods, except boiling when it lost 14%. Analysis of the ABTS radical scavenging capacity of the different vegetables showed that the highest losses occurred in garlic with all the methods, except microwaving. Among the vegetables that increased their TEAC values were green bean, celery, and carrot after all cooking methods (except green bean after boiling). These 3 types of vegetables showed a low ABTS radical scavenging capacity. According to the method of analysis chosen, griddling, microwave cooking, and baking alternately produce the lowest losses, while pressure-cooking and boiling lead to the greatest losses; frying occupies an intermediate position. In short, water is not the cook's best friend when it comes to preparing vegetables.

Influence of agricultural practices on the quality of sweet pepper fruits as affected by the maturity stage

AbstractBackground:Peppers are popular vegetables because of their colour, taste and nutritional value. The levels of vitamin C, carotenoids and phenolic compounds in peppers and other vegetables depend on several factors, including cultivar, agricultural practice and maturity stage.Results:In this study the effects of maturation and type of agricultural practice (organic or conventional) on the ascorbic acid, total carotenoid and total phenolic contents and colour parameters of sweet peppers (Capsicum annuum cv. Almuden) grown in a controlled greenhouse were determined. Levels of vitamin C, phenolic compounds and carotenoids increased during ripening, with red sweet peppers having higher contents of these bioactive compounds. Moreover, peppers grown under organic culture had higher vitamin C, phenolic and carotenoid levels than those grown under conventional culture. With respect to colour parameters, organic red peppers had higher values of L*, a*, b*, C* and Hab than conventional red peppers, giving them a higher intensity of red colour.Conclusion:Thus organic farming had a positive effect on the nutritional content of peppers, increasing the vitamin C activity and the level of phenolic compounds, both implicated in the antioxidant activity of vegetables, and the content of carotenoids, implicated in the colour variance observed in pepper fruits. Copyright © 2007 Society of Chemical Industry

Fat‐Soluble Antioxidant Concentrations and Lipophilic Antioxidant Activities in Fruits, Vegetables and Legumes Harvested in Korea.

There have been efforts to measure antioxidant activity in foods especially in fruits and vegetables (F & V). In this study, antioxidant activities of vegetables(n=67), fruits(n=21) and legumes(n=7) commonly consumed in Korea were determined by both Lipophilic Antioxidant Performance (LAP) and Oxygen Radical Absorbance Capacity(ORAC) assays. In addition, the contents of carotenoids (all-trans-β-carotene, 9-cis-β-carotene, α-carotene, cryptoxanthin, zeaxanthin, lutein, all-trans-lycopene and cis-lycopene) and tocopherols were evaluated by a reverse phase HPLC system using a C30 column. Sample were lyophilized and lipophilic components were extracted with methanol and tetrahydrofuran for LAP, carotenoid and tocopherol analyses. Acetone was used to extract lipophilic components for ORAC. Results green vegetables mainly contained lutein, all-trans β-carotene, and 9-cis-β-carotene and these carotenoids were contributed to LAP values of vegetables. Red and orange vegetables, fruits and legumes were significant sources of α-carotene, cryptoxanthin, zeaxanthin and lycopene. The carotenoid contents in Korean F & V greatly different from the values in the US and Japan database probably due to the different cultivar and cultivated conditions. Positive correlations were found between LAP and β-carotene, lutein+zeaxanthin, and total carotenoids (p<0.001). A positive correlation was also found between values of LAP and ORAC (p<0.001).

Antioxidant Activity of Selected Fruits and Vegetables Grown in Turkey

Antioxidant activities of different fruits (apple, quince, grape, pear and pomegranate) and vegetables (potato, onion, spring onion, red radish and red cabbage) were determined. In addition, total phenolic and flavonoid contents of those samples were assessed. Among fruits, pomegranate had the highest (62.7%) antioxidant activity, followed by quince (60.4%), grape (26.6%), apple (25.7%) and pear (13.7%). The antioxidant activity of vegetables ranged from 40.8% (red cabbage) to 12.5% (onion). Total phenolic and flavonoid contents in fruits varied from 326 to 4306 mg of catechin kg-1 and from 282 to 2115 mg of catechin kg-1, respectively. Those in vegetables ranged between 536 and 2166 mg of catechin kg-1 and between 153 and 842 mg of catechin kg-1, respectively. A high and significant correlation between antioxidant activity and total phenolic content was determined in fruits (r2 = 0.9307, P < 0.01) and vegetables (r2 = 0.9361 P < 0.05). However, flavonoid content was not significantly correlated with antioxidant activity in vegetables, while it was significantly related in fruits (r2 = 0.8316, P < 0.01). It was observed that total phenolic content is the major contributor to the antioxidant activity of fruits and vegetables.