Effects of extraction solvent mixtures on antioxidant activity evaluation and their extraction capacity and selectivity for free phenolic compounds in barley (Hordeum vulgare L.)

Four kinds of solvent extracts from three Chinese barley varieties (Ken-3, KA4B, and Gan-3) were used to examine the effects of extraction solvent mixtures on antioxidant activity evaluation and their extraction capacity and selectivity for free phenolic compounds in barley through free radical scavenging activity, reducing power and metal chelating activity, and individual and total phenolic contents. Results showed that extraction solvent mixtures had significant impacts on antioxidant activity estimation, as well as different extraction capacity and selectivity for free phenolic compounds in barley. The highest DPPH* and ABTS*+ scavenging activities and reducing power were found in 80% acetone extracts, whereas the strongest *OH scavenging activity, O2*- scavenging activity, and metal chelating activity were found in 80% ethanol, 80% methanol, and water extracts, respectively. Additionally, 80% acetone showed the highest extraction capacity for (+)-catechin and ferulic, caffeic, vanillic, and p-coumaric acids, 80% methanol for (-)-epicatechin and syringic acid, and water for protocatechuic and gallic acids. Furthermore, correlations analysis revealed that TPC, reducing power, DPPH* and ABTS*+ scavenging activities were well positively correlated with each other (p < 0.01). Thus, for routine screening of barley varieties with higher antioxidant activity, 80% acetone was recommended to extract free phenolic compounds from barley. DPPH* scavenging activity and ABTS*+ scavenging activity or reducing power could be used to assess barley antioxidant activity.     

Antioxidant properties of bran extracts from Trego wheat grown at different locations

The effects of growing conditions during the grain-filling period, including high temperature stress, total solar radiation, and average daily solar radiation, on the antioxidant properties of Trego wheat were evaluated. Bran extracts were prepared from Trego wheat, grown at four nonirrigated and one irrigated location in Colorado, and compared for their radical scavenging activities against ABTS*+ and DPPH*, Fe(2+) chelating capacities, and total phenolic contents. Significant differences in radical scavenging activities, chelating capacities, and total phenolic contents were detected among Trego bran samples grown at different locations, suggesting that growing conditions may influence the antioxidant properties of wheat. The bran sample obtained from Fort Collins had the strongest scavenging activity against either ABTS*+ or DPPH* radicals and the greatest chelating activity, whereas the highest total phenolic content was detected in bran samples from Walsh, indicating that each antioxidant activity may respond to the environmental changes differently. Positive correlations were detected between the DPPH* scavenging activity and either total solar radiation (r = 0.97, p = 0.03) or average daily solar radiation (r = 0.97, p = 0.03). In addition, HPLC analysis detected the presence of ferulic, syringic, vanillic, p-hydroxybenzoic, and coumaric acids in wheat bran. Additional research is needed to further investigate the effects of environmental conditions and the interactions between genotype and environmental factors on the antioxidant properties of wheat to promote the production of wheat with improved antioxidant properties by optimizing the growing conditions for a selected genotype.     

Antioxidant properties of bran extracts from "Akron" wheat grown at different locations

Bran extracts of Akron wheat grown at four nonirrigated and one irrigated testing locations were examined and compared for their free radical scavenging properties against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(*)) and the radical cation ABTS(*)(+), chelating capacities, and total phenolic content (TPC) to determine the potential effects of environmental factors on the antioxidant properties of hard winter wheat. The environmental factors included total solar radiation, average daily solar radiation, and number of hours exceeding 32 degrees C. The results showed that bran samples from different growing locations may significantly differ in their radical scavenging activities against both DPPH(*) and ABTS(*)(+), chelating capacities, and TPC. A significant negative correlation was detected between the chelating activities of the bran samples from the four nonirrigated locations and total solar or daily average solar radiation (r = -0.999 and P = 0.001). These data suggest potential influences of growing conditions on the antioxidant properties of hard winter wheat and the possibility of producing wheat that is strong in a selected antioxidant property by optimizing the growing conditions of a selected wheat variety. More research is required to further investigate the relationship among antioxidant properties and environmental factors using different wheat varieties and larger sample sizes.     

Antioxidant contents and antioxidative properties of traditional rye breads

The purpose of this research was to find out the effect of flour extraction rate on the antioxidative properties of traditional rye bread and then to compare the bioactive compounds content and antioxidant properties of rye breads with commercial wheat roll. Four types of rye flour with different extraction rates of 100 (whole meal dark flour), 95 (brown flour), 90 (brown flour), and 70% (light flour) originated from Warko rye cultivar were used for traditional bread baking with sourdough fermentation. Four types of the respective rye breads were analyzed for their potentially beneficial components, including tocopherols and tocotrienols, total phenolics and flavonoids, reduced glutathione, and inositol hexaphosphates. Moreover, the phenolic acids profile was provided. The Trolox equivalent antioxidant capacity (TEAC) of the breads was evaluated using free radical scavenging activities of 80% methanol extracts against ABTS*+ radical cation (ABTS radical cation decolorization method) whereas radical scavenging activity (RSA) was determined against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH*). The superoxide dismutase-like activity (SOD-like activity) was evaluated as free radical scavenging activities of PBS extracts against superoxide anion radicals (O2*-). The results were compared to whole meal rye bread as well as to wheat roll taken as representative example of wheat based bakery product. The studies showed that flour extraction rates strongly affected the content of bioactive compounds and antioxidative properties of traditionally baked rye breads. The incorporation of the rye flours with extraction rates from 100 down to 70% in the formulation caused decrease in tocopherol (T), tocotrienol (T3), inositol hexaphosphate (IP6), and phenolic compound (TPC) contents in rye breads. No changes in reduced glutathione (GSH) contents were noted between each type of rye bread. A significant decrease in Trolox equivalent antioxidant capacity and radical DDPH scavenging activity was also found in bread formulated on flour with an extraction rate of 70% in comparison to the breads formulated on flour with extraction rates from 100 to 90%. The highest SOD-like activity was noted for rye bread formulated on flour with an extraction rate of 70%. The four types of rye breads showed better antioxidative properties and higher antioxidant contents when compared to wheat roll with one exception made to tocopherols and tocotrienols.     

Free radical scavenging properties of wheat extracts

Three hard winter wheat varieties (Akron, Trego, and Platte) were examined and compared for their free radical scavenging properties and total phenolic contents (TPC). Free radical scavenging properties of wheat grain extracts were evaluated by spectrophotometric and electron spin resonance (ESR) spectrometry methods against stable 2,2-diphenyl-1-picryhydrazyl radical (DPPH*) and radical cation ABTS*+ (2,2'-azino-di[3-ethylbenzthiazoline sulfonate]). The results showed that the three wheat extracts differed in their capacities to quench or inhibit DPPH* and ABTS*+. Akron showed the greatest activity to quench DPPH radicals, while Platte had the highest capacity against ABTS*+. The ED50 values of wheat extracts against DPPH radicals were 0.60 mg/mL for Akron, 7.1 mg/mL for Trego, and 0.95 mg/mL for Platte under the experimental conditions. The trolox equivalents against ABTS*+ were 1.31 +/- 0.44, 1.08 +/- 0.05, and 1.91 +/- 0.06 micromol/g of grain for Akron, Trego, and Platte wheat, respectively. ESR results confirmed that wheat extracts directly reacted with and quenched free radicals. The TPC were 487.9 +/- 927.8 microg gallic acid equivalents/g of grain. No correlation was observed between TPC and radical scavenging capacities for DPPH* and ABTS*+ (p = 0.15 and p > 0.5, respectively).     

Antioxidant properties of pearled barley fractions

Two barley varieties (Falcon and AC Metcalfe) were separated by pearling into seven fractions and subsequently extracted with 80% methanol. The extracts, after solvent removal, were evaluated for their radical scavenging efficacy using Trolox equivalent antioxidant capacity (TEAC). The radical scavenging capacity of the extracts was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, oxygen radical absorbance capacity (ORAC(FL)), and superoxide radical assays and a photoinduced chemiluminescence technique. In both barley varieties the outermost fraction (F1) yielded the highest phenolic content. In general, Falcon had a significantly higher total phenolic content than AC Metcalfe. A similar trend was observed for TEAC, DPPH, and superoxide radical scavenging capacities of the extracts. The contents of water-soluble antioxidants of Falcon and AC Metcalfe were 1.15-12.98 and 2.20-12.25 micromol of Trolox equiv/(g of defatted material), while the corresponding lipid-soluble counterparts varied from 1.44 to 4.70 micromol of alpha-tocopherol equiv/(g of defatted material). Phenolic acids, namely, vanillic, caffeic, p-coumaric, ferulic, and sinapic acids, were identified by HPLC in barley fractions.     

Assessment of antioxidant activity of cane brown sugars by ABTS and DPPH radical scavenging assays: determination of their polyphenolic and volatile constituents

Seven cane brown sugars (four from La Réunion, two from Mauritius, and one from France) were investigated for their polyphenol content and volatile composition in relation to their free radical scavenging capacity determined by ABTS and DPPH assays. The thin layer coated on the sugar crystal was extracted by Soxhlet extractor with dichloromethane. The volatile compounds of brown sugars were studied by GC-MS, and 43 compounds were identified. The total phenolic content of brown sugars was determined according to the Folin-Ciocalteu method. Phenolic compounds were quantified in the brown sugar extracts by LC-UV-ESI-MS. Brown sugar aqueous solutions exhibited weak free radical scavenging activity in the DPPH assay and higher antioxidant activity in the ABTS assay at relatively high concentration. The brown sugar extracts showed interesting free radical scavenging properties despite the low concentration of phenolic and volatile compounds. Sugar is a common foodstuff traditionally used for its sweetening properties, which might be accompanied by antioxidant properties arising from molecules (polyphenols, Maillard products) other than sucrose of the cane brown sugars.     

电解水对荞麦芽酚酸含量及抗氧化能力的影响

为了能够更好地将发芽荞麦用作制备功能食品的原料,本研究采用理化指标不同的电解水制备荞麦芽,考察荞麦的发芽率及芽长、总酚含量、DPPH和ABTS自由基清除能力,以及铁离子还原力在发芽期间的动态变化,并分析各处理组发芽第7天荞麦芽中游离酚和结合酚种类和含量。结果表明,在7 d观测期内,电解水有利于荞麦发芽及生长。不同评价方法测定荞麦芽抗氧化能力的结果显示,pH值11.13电解水处理组发芽1~3 d荞麦芽总酚含量及抗氧化水平均显著高于对照组(P<0.05),而pH值3.21、pH值5.02和pH值9.02电解水处理组发芽5~7 d荞麦芽总酚含量及抗氧化水平均显著高于对照组(P<0.05)。各处理组荞麦芽中主要的游离酚均为绿原酸,且电解水处理组荞麦芽游离绿原酸含量均显著高于对照组(P<0.05)。自来水处理组荞麦芽主要结合酚为香豆酸,而电解水处理组荞麦芽主要结合酚为咖啡酸。本研究结果为电解水应用于功能性荞麦芽的制备提供了理论依据。     

Effects of genotype and environment on the antioxidant properties of hard winter wheat bran

Recent consumer interest in controlling and preventing chronic diseases through improved diet has promoted research on the bioactive components of agricultural products. Wheat is an important agricultural and dietary commodity worldwide with known antioxidant properties concentrated mostly in the bran fraction. The objective of this study was to determine the relative contributions of genotype (G) and growing environment (E) to hard winter wheat bran antioxidant properties, as well as correlations of these properties to growing conditions. Bran samples of 20 hard winter wheat varieties grown in two locations were examined for their free radical scavenging capacities against DPPH, ABTS cation, peroxyl (ORAC), and superoxide anion radicals and chelating properties, as well as their total phenolics and phenolic acid compositions. Results showed significant differences for all antioxidant properties tested and multiple significant correlations between these properties. A factorial designed analysis of variance for these data and pooled previously published data showed similar results for four of the six antioxidant properties, indicating that G effects were considerably larger than E effects for chelating capacity and DPPH radical scavenging properties, whereas E was much stronger than G for ABTS cation radical scavenging capacity and total phenolics, although small interaction effects (GxE) were significant for all antioxidant properties analyzed. Results also showed significant correlations between temperature stress or solar radiation and some antioxidant properties. These results indicate that each antioxidant property of hard winter wheat bran is influenced differently by genotype and growing conditions.     

体外模拟胃肠消化对不同热处理荷叶中酚类物质释放量及抗氧化活性的影响

为探讨体外模拟胃肠消化对不同热处理荷叶中酚类物质释放及抗氧化活性的影响,采用真空微波、湿热蒸汽和煮沸3种热加工方式和体外模拟胃肠消化对不同生长期荷叶进行处理。结果表明,荷叶中酚类物质的释放与荷叶生长过程中荷叶直径大小呈正相关,其中直径为56 cm的荷叶总酚释放量最高。此外,在不同消化方式不同热处理下,真空微波干燥处理的荷叶(V56)总酚和总黄酮释放量均最高,且其FRAP、ABTS抗氧化能力也最强。与对照组相比,模拟胃液处理显著提高了真空微波热处理组荷叶的总酚释放量,显著降低了煮沸处理组荷叶的总酚释放量,对湿热蒸汽处理组荷叶的总酚释放量无影响,而模拟胃液处理均显著降低了不同热处理组荷叶的总黄酮释放量;模拟肠液处理均显著增加了不同热处理组荷叶的总酚和总黄酮释放量。与对照组相比,模拟胃液消化显著提高了真空微波处理组和湿热蒸汽处理组荷叶的FRAP抗氧化能力,降低了煮沸处理组荷叶的FRAP抗氧化能力;模拟肠液消化显著提高了真空微波组荷叶的FRAP抗氧化能力。模拟胃液消化中真空微波处理组的ABTS抗氧化能力与对照相比有所降低,而模拟肠液消化显著提高了3种热加工处理组荷叶的ABTS抗氧化能力。本研究结果为荷叶的开发利用提供了技术支撑和理论依据。     

Comparison of Swiss red wheat grain and fractions for their antioxidant properties

Swiss red wheat grain, bran, aleurone, and micronized aleurone were examined and compared for their free radical scavenging properties against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH*), radical cation ABTS*+ and peroxide radical anion O(2)*-, oxygen radical absorbance capacity (ORAC), chelating capacity, total phenolic content (TPC), and phenolic acid composition. The results showed that micronized aleurone, aleurone, bran, and grain may significantly differ in their antioxidant properties, TPC, and phenolic acid composition. Micronized aleurone had the greatest antioxidant activities, TPC, and concentrations of all identified phenolic acids, suggesting the potential of postharvesting treatment on antioxidant activities and availability of TPC and phenolic acids. Ferulic acid was the predominant phenolic acid in Swiss red wheat and accounted for approximately 57-77% of total phenolic acids on a weight basis. Ferulic acid concentration was well correlated with scavenging activities against radical cation and superoxide anion, TPC, and other phenolic acid concentrations, suggesting the potential use of ferulic acid as a marker of wheat antioxidants. In addition, 50% acetone and ethanol were compared for their effects on wheat ORAC values. The ORAC value of 50% acetone extracts was 3-20-fold greater than that of the ethanol extracts, indicating that 50% acetone may be a better solvent system for monitoring antioxidant properties of wheat. These data suggest the possibility to improve the antioxidant release from wheat-based food ingredients through postharvesting treatment or processing.     

Vitamin C equivalent antioxidant capacity (VCEAC) of phenolic phytochemicals

To express the antioxidant capacity of plant foods in a more familiar and easily understood manner (equivalent to vitamin C mg/100 g), two stable radical species, ABTS(*)(-) and DPPH(*), commonly used for antioxidant activity measurements, were employed independently to evaluate their efficacies using apple polyphenolic extracts and seven polyphenolic standards including synthetic Trolox. Their antioxidant activities were expressed as vitamin C equivalent antioxidant capacity (VCEAC) in mg/100 g apple or mg/100 mL of the reference chemical compounds in 10 and 30 min using the ABTS(*)(-) and DPPH(*) scavenging assays, respectively. The antioxidant capacity of Gala apples and seven phenolic standards, determined by both ABTS(*)(-) and DPPH(*) scavenging assays, showed a dose-response of the first-order. Fresh Gala apples had a VCEAC of 205.4 +/- 5.6 mg/100 g using the ABTS assay, and the relative VCEACs of phenolic standards were as follows: gallic acid > quercetin > epicatechin > catechin > vitamin C > rutin > chlorogenic acid > Trolox. With the DPPH radical assay, the VCEAC of fresh Gala apples was 136.0 +/- 6.6 mg/100 g, and the relative VCEACs of seven phenolic standards were, in decreasing order, as follows: gallic acid > quercetin > epicatechin > catechin > or = vitamin C > Trolox > rutin > chlorogenic acid. Because the ABTS assay can be used in both organic and aqueous solvent systems, employs a specific absorbance at a wavelength remote from the visible region, and requires a short reaction time, it is a more desirable method than the DPPH assay. Therefore, it is recommended that antioxidant capacity be expressed as vitamin C mg/100 g equivalent (VCEAC) using the ABTS assay.     

Antioxidant activity and phenolic composition of wild, edible, and medicinal fennel from different Mediterranean countries

Fennel (Foeniculum vulgare Mill.) is a typical aromatic plant of the Mediterranean area, long used as a medicinal and spice herb. Fennel is also well-known for its essential oil, which has been extensively studied for many years owing to its commercial importance. In this work, the antioxidant activity and the total phenolic and flavonoid contents, as well as the quantitative determination of individual flavonoids and phenolic acids of wild, edible, and medicinal fennel from different Mediterranean countries, have been determined. The antioxidant activity was measured as the free radical (DPPH), hydroxyl radical, and superoxide anion scavenging activities. Wild fennel was found to exhibit a radical scavenging activity, as well as a total phenolic and total flavonoid content, higher than those of both medicinal and edible fennels.     

Free radical scavenging properties and phenolic content of Chinese black-grained wheat

Free radical scavenging properties and phenolic content of extracts from a novel Chinese black-grained wheat were evaluated for comparison with selected wheat controls. Extracts of bran and whole meal were compared for their scavenging activities against the 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical. The total phenolic content and phenolic acid levels were determined using colorimetric and high-performance liquid chromatography (HPLC) methods, respectively. There were significant differences in radical scavenging activities and phenolic contents among bran or whole meal samples of Chinese black-grained wheat and selected wheat controls. Chinese black-grained wheat had the strongest scavenging activity and the highest total phenolic content among the wheat samples. The scavenging activity and total phenolic content of wheat bran was generally twice as high as that of whole meal. A positive correlation was found between DPPH radical scavenging activity and total phenolic content of bran (R = 0.86) and whole meal (R = 0.96). In addition, HPLC analysis detected the presence of gallic, p-hydroxybenzoic, caffeic, syringic, p-coumaric, vanillic, gentisic, o-coumaric acid, and ferulic acids in wheat bran. Ferulic acid content was highest among the phenolic acids. Chinese black-grained wheat may be considered as a potential source of natural antioxidants given its high free radical scavenging ability and phenolic content. Additional research is needed to further investigate other phenolic compounds and evaluate their contribution to the antioxidant activity in order to understand the nutraceutical value of the novel black-grained wheat genotype.     

Antioxidant activity of glyceollins derived from soybean elicited with Aspergillus sojae

The extract of soybean exposed to biotic elicitors such as food-grade fungus is known to have antioxidant activity. Glyceollins were major bioactive compounds present in soybean elicited by fungi and shown to have antifungal and anticancer activities. The purpose of present study was to evaluate the antioxidant activities of glyceollins by measuring ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, singlet oxygen quenching, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, hydroxyl radical scavenging activity, and lipid peroxidation inhibition. In addition, the antioxidant potential of glyceollins were measured by a fluorescent probe, 2',7'-dichlorofluorescin diacetate (DCFDA), and dihydroethidium (DHE) in mouse hepatoma hepa1c1c7 cells in which they were insulted with H2O2 to generate reactive oxygen species (ROS). Glyceollins showed a strong reducing power and inhibited lipid peroxidation, with significant scavenging activities of radicals including singlet oxygen, superoxide anion, ABTS, and DPPH. We also found that glyceollins significantly suppressed H2O2-induced ROS production in hepa1c1c7 cells. Therefore, glyceollins deserve further study as natural antioxidants and nutraceuticals.     

Effect of heat treatment of camelina (Camelina sativa) seeds on the antioxidant potential of their extracts

The effect of different heat treatments of camelina (Camelina sativa) seeds on the phenolic profile and antioxidant activity of their hydrolyzed extracts was investigated. The results showed that total phenol contents increased in thermally treated seeds. Heat treatment affected also the quantities of individual phenolic compounds in extracts. Phenolics in unheated camelina seeds existed in bound rather than in free form. A temperature of 160 °C was required for release of insoluble bound phenolics, whereas lower temperatures were found to be optimal to liberate those present as soluble conjugates. The best reducing power and alkyl peroxyl radical scavenging activity in the emulsion was expressed by phenolics which were bound to the cell wall, whereas the best iron chelators and 2,2-diphenyl-1-picrylhydrazyl (DPPH?) radical scavengers were found to be those present in free form. The heat treatment of seeds up to 120 °C increased the reducing power and DPPH? radical scavenging ability of extracts, but negatively affected iron chelating ability and their activity in an emulsion against alkyl peroxyl radicals.     

Carotenoid, tocopherol, phenolic acid, and antioxidant properties of Maryland-grown soft wheat

Consumers' desires to either reduce the risk of or manage a specific health condition through improved diet have stimulated the research of agricultural products for their potential health beneficial components such as tocopherols and natural antioxidants. Soft wheat is one of the major crops in Maryland, with little information available about its potentially beneficial components. This study examined eight selected Maryland-grown soft wheat varieties or experimental lines for their potential beneficial components including tocopherols, carotenoids, total phenolics and phenolic acids and their antioxidant properties, including Fe(2+) chelating capacity and free radical scavenging activities against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(*) ), radical cation ABTS(*)(+), and oxygen radical (ORAC). The results showed that all tested soft wheat grain samples contained alpha-tocopherol, with a range of 3.4-10.1 microg/g. Lutein was the primary carotenoid present in the grain samples at a level of 0.82-1.14 microg/g, along with significant amounts of zeaxanthin and beta-carotene. Vanillic, syringic, p-coumaric, and ferulic acids were found in soluble free, soluble conjugated, and insoluble bound forms in the grain extracts, with ferulic acid as the predominant phenolic acid. The eight soft wheat varieties differed in their antioxidant properties. The tested wheat grain samples exhibited ED(50) values against DPPH(*) of 23-27 mg of grain equiv/mL, ORAC of 32.9-48 micromol of Trolox equiv (TE)/g, and ABTS(*)(+) scavenging capacity of 14.3-17.6 micromol of TE/g. These data suggest the possibility of producing soft wheat varieties rich in selected health beneficial factors for optimum human nutrition though breeding programs.     

Cocoa has more phenolic phytochemicals and a higher antioxidant capacity than teas and red wine

Black tea, green tea, red wine, and cocoa are high in phenolic phytochemicals, among which theaflavin, epigallocatechin gallate, resveratrol, and procyanidin, respectively, have been extensively investigated due to their possible role as chemopreventive agents based on their antioxidant capacities. The present study compared the phenolic and flavonoid contents and total antioxidant capacities of cocoa, black tea, green tea, and red wine. Cocoa contained much higher levels of total phenolics (611 mg of gallic acid equivalents, GAE) and flavonoids (564 mg of epicatechin equivalents, ECE) per serving than black tea (124 mg of GAE and 34 mg of ECE, respectively), green tea (165 mg of GAE and 47 mg of ECE), and red wine (340 mg of GAE and 163 mg of ECE). Total antioxidant activities were measured using the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays and are expressed as vitamin C equivalent antioxidant capacities (VCEACs). Cocoa exhibited the highest antioxidant activity among the samples in ABTS and DPPH assays, with VCEACs of 1128 and 836 mg/serving, respectively. The relative total antioxidant capacities of the samples in both assays were as follows in decreasing order: cocoa > red wine > green tea > black tea. The total antioxidant capacities from ABTS and DPPH assays were highly correlated with phenolic content (r2 = 0.981 and 0.967, respectively) and flavonoid content (r2 = 0.949 and 0.915). These results suggest that cocoa is more beneficial to health than teas and red wine in terms of its higher antioxidant capacity.     

Antioxidant activity of South African red and white cultivar wines: free radical scavenging

The free radical scavenging activity of South African red (n = 46) and white (n = 40) cultivar wines was determined using 2,2'-azinobis(3-ethylbenzothialozinesulfonic acid) radical cations (ABTS(.+)) and 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH.). The total antioxidant activities (TAA) of red and white wines using ABTS(.+) were 14.916 and 0.939 mM Trolox, respectively, at corresponding total phenol (TP) contents of 2339.0 and 273.8 mg of gallic acid equiv/L. Ruby Cabernet wines had the lowest TAA(ABTS) (13.177 mM Trolox) of the red wines, whereas the TAA(ABTS) values of Chardonnay and Chenin blanc wines were the highest (1.060 mM Trolox) and lowest (0.800 mM Trolox) of the white wines. The TAA(DPPH) values were of the same magnitude as the TAA(ABTS) values, and similar trends were observed. TAA correlated (P < 0.001) with total phenol content of red (r = 0.935) and white (r = 0.907) wines, as well as flavanol content of red wines (r = 0.866) and tartaric acid ester content of white wines (r = 0.767). Canonical discriminant analysis using phenolic composition and antioxidant activity was applied to differentiate between red and white cultivar wines.     

Edible neotropical blueberries: antioxidant and compositional fingerprint analysis

Edible blueberry species are well recognized for their potential health benefits. Ericaceae fruits including the North American highbush blueberry (Vaccinium corymbosum L.) and five less common edible blueberry relatives from the New World tropics, Anthopterus wardii Ball, Cavendishia grandifolia Hoerold, Macleania coccoloboides A. C. Smith, Sphyrospermum buxifolium Poeppig & Endlicher, and Sphyrospermum cordifolium Benth, were investigated for their antioxidant properties and phenolic profiles. The neotropical berries C. grandifolia and A. wardii exhibited significantly higher 1,1-diphenyl-2-picrylhydrazyl (DPPH(?)) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS(??+)) free radical scavenging and iron chelation activities than V. corymbosum. Total phenolic content and high-performance liquid chromatography with photodiode array detection (HPLC-PDA) compositional fingerprint analyses were also carried out. Significant correlations were observed among total phenolic contents, DPPH(?) and ABTS(??+) scavenging, and iron chelation activities. By use of HPLC-PDA, the phenolic constituents in the berries were identified as chlorogenic acid, p-coumaric acid, hyperoside, quercetin-3-O-glucoside, isoorientin, isovitexin, orientin and vitexin. Principal component analysis reduced the dimensions of antioxidant and total phenolic data to two components, which accounted for 95% of total variation among the six fruits. Each fruit species formed its own cluster, and therefore the antioxidant profile of each species was shown to be distinct.