Antioxidant capacities and phenolics levels of French wines from different varieties and vintages.

Phenolics from grapes and wines can play a role against oxidation and development of atherosclerosis. Levels of phenolics, major catechins [(+)-catechin, (-)-epicatechin, procyanidin dimers B1, B2, B3, and B4], phenolic acids (gallic acid and caffeic acid), caftaric acid, malvidin-3-glucoside, peonidin-3-glucoside, and cyanidin-3-glucoside were quantified by HPLC with UV detection for 54 French varietal commercial wines taken from southern France to study the antioxidant capacity and the daily dietary intake of these compounds for the French population. The highest antioxidant capacity was obtained with red wines and ranged from 12.8 mmol/L (Grenache) to 25.2 mmol/L (Pinot Noir). For white wines, Chardonnay enriched in phenolics by special wine-making was found to have an antioxidant capacity of 13.8 mmol/L, comparable to red wine values. For red wines classified by vintages (1996-1999) antioxidant capacities were approximately 20 mmol/L and then decreased to 13.4 mmol/L for vintages 1995-1991. Sweet white wines have 1.7 times more antioxidant capacity (3.2 mmol/L) than dry white wines (1.91 mmol/L). On the basis of a still significant French wine consumption of 180 mL/day/person, the current daily intake of catechins (monomers and dimers B1, B2, B3, and B4) averaged 5 (dry white wine), 4.36 (sweet white wines), 7.70 (rosé wines), 31.98 (red wines), and 66.94 (dry white wine enriched in phenolic) mg/day/resident for the French population. Red wine, and particularly Pinot Noir, Egiodola, Syrah, Cabernet Sauvignon, and Merlot varieties, or Chardonnay enriched in phenolics during wine-making for white varieties contribute to a very significant catechin dietary intake.     

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.     

Antioxidant and antiradical activities in extracts of hazelnut kernel (Corylus avellana L.) and hazelnut green leafy cover

Phenolic compounds in the aqueous systems were extracted, from hazelnut kernel (HK) and hazelnut green leafy cover (HGLC), with 80% (v/v) ethanol (HKe and HGLCe) or 80% (v/v) acetone (HKa and HGLCa). The extracts were examined for their phenolic and condensed tannin contents and phenolic acid profiles (free and esterified fractions) as well as antioxidant and antiradical activities by total antioxidant activity (TAA), antioxidant activity in a beta-carotene-linoleate model system, scavenging of DPPH (2,2-diphenyl-1-picrylhydrazyl) radical, and reducing power. Significant differences (p < 0.05) in the contents of total phenolics, condensed tannins, and TAA existed among the extracts that were examined. HGLCa extract had the highest content of total phenolics (201 mg of catechin equivalents/g of extract), condensed tannins (542 mg of catechin equivalents/g of extract), and TAA (1.29 mmol of Trolox equivalents/g of extract) followed by HGLCe, HKa, and HKe extracts, respectively. Five phenolic acids (gallic acid, caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid) were tentatively identified and quantified, among which gallic acid was the most abundant in both free and esterified forms. The order of antioxidant activity in a beta-carotene-linoleate model system, the scavenging effect on DPPH radical, and the reducing power in all extracts were in the following order: HGLCa > HGLCe > HKa > HKe. These results suggest that both 80% ethanol and acetone are capable of extracting phenolics, but 80% acetone was a more effective solvent for the extraction process. HGLC exhibited stronger antioxidant and antiradical activities than HK itself in both extracts and could potentially be considered as an inexpensive source of natural antioxidants.     

Effects of extraction methods on phenolic contents and antioxidant activity in aerial parts of Potentilla atrosanguinea Lodd. and quantification of its phenolic constituents by RP-HPLC

The effects of different solvent systems (methanol, ethanol, acetone, and their 50% aqueous concentrations) and extraction procedures (microwave, ultrasound, Soxhlet and maceration) on the antioxidant activity of aerial parts of Potentilla atrosanguinea were investigated by three different bioassays: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays and ferric reducing antioxidant potential (FRAP). The 50% aqueous ethanol extracts exhibited strong antioxidant activity measured in terms of Trolox equivalent antioxidant capacity (TEAC) [(54.34 to 122.96, 29.82 to 101.22 and 13.64 to 41.43) mg of Trolox/g] with ABTS (*+), DPPH (*) and FRAP assays, respectively. In general, TEAC of Soxhlet extracts was found to be 1.8 and 3 times higher than ultrasound and maceration but slightly (1.2 times) higher than microwave. A positive correlation (r(2) = 0.931 to 0.982) was observed between total polyphenol (TPC) and total flavonoid (TFC) contents which ranged between 26.7 to 30.7 mg/g gallic acid equivalent and 16.8 to 20.8 mg/g quercetin equivalent respectively, with antioxidant activity. In addition, some of its bioactive phenolic constituents which contribute largely toward antioxidant potential such as chlorogenic acid, catechin, caffeic acid, p-coumaric acid and quercetin were also quantified in different extracts by RP-HPLC.     

Polyphenolic compounds, antioxidant capacity, and quinone reductase activity of an aqueous extract of Ardisia compressa in comparison to mate (Ilex paraguariensis) and green (Camellia sinensis) teas

Aqueous extracts of the leaves of Ardisia compressa (AC) have been used in folk medicine to treat various liver disorders including liver cancer. The objective of this study was to partially characterize and determine the total polyphenol content, antioxidant capacity, and quinone reductase activity of A. compressa tea in comparison to mate (Ilex paraguariensis, MT) and green (Camellia sinensis,GT) teas. Total polyphenol content, antioxidant capacity, and phase II enzyme induction capacity were measured by the modified Folin-Ciocalteu, ORAC, and quinone reductase (QR) assays, respectively. The major polyphenols in AC were not catechins. HPLC retention times and standard spikes of AC indicated the presence of gallic acid, epicatechin gallate, ardisin and kaempferol. Using catechin as standard, the total polyphenol value of AC (36.8 +/- 1.1 mg/mg DL) was significantly lower than GT (137.2 +/- 5.8 mg equivalent of (+)-catechin/mg dried leaves, DL) and MT (82.1 +/- 3.8 mg/mg DL) (P < 0.001). Antioxidant capacity (AC, 333; GT, 1346; MT, 1239 mmol Trolox equivalents/g DL) correlated with total polyphenol values (r(2) = 0.86, P < 0.01). AC (4.5-12.5 microg/mL) induced QR enzyme, in Hepa1c1c7 cells, up to 15%. MT and GT showed no induction at the concentrations tested (0.5-10.5 and 0.5-12.5 mg/mL, respectively). These results suggest that AC has a different mechanism of protection against cytotoxicity that is not related to its antioxidant capacity. Further studies are needed to determine such mechanisms and to explore its potential as a chemopreventive or therapeutic agent.     

Changes during storage in conventional and ecological wine: phenolic content and antioxidant activity

Polyphenol content, free radical scavenging capacity, and changes during storage over 7 months in the dark were studied in ecological and conventional red and white wines. In red wines, the most changeable components during storage were the anthocyanins since during storage anthocyanins content decreased 88% in conventional wine and 91% in ecological wine. Initially, the total flavonol contents of the conventional and ecological red wines were 163.88 +/- 2.69 and 153.58 +/- 1.71 mg/L, respectively, and no significant variations occurred during storage. No differences in hydroxycinnamic acid derivatives content between conventional and ecological red and white wines were observed. The flavonol level in white wines was very low, as expected since these compounds are found in grape skin. The initial antioxidant activity was 5.37 +/- 0.14 and 5.82 +/- 0.31 mM equivalents Trolox for conventional and ecological red wines, respectively; no significant differences were observed (p = 0.2831), and these values were 7-8 times higher than the antioxidant activity observed in conventional and ecological white wine. In contrast with other studies, the total concentrations of phenolic compounds in conventional and ecological red and white wines were not related to antioxidant activity (p > 0.05). In red wines, no significant differences were observed in the antioxidant activity of ecological and conventional red wine (p = 0.28), while in white wine significant differences were observed in the antioxidant activity between conventional and ecological white wine (p = 0.006).     

Anthocyanin and proanthocyanidin content in selected white and red wines. Oxygen radical absorbance capacity comparison with nontraditional wines obtained from highbush blueberry

Antioxidant capacity, as measured by oxygen radical absorbance capacity (ORAC(PE)), total phenolic, total and individual anthocyanins, and proanthocyanidin fraction contents were evaluated in red and white wines from grapes. A comparison in terms of antioxidant capacity is made with nontraditional wines made from highbush blueberry. Blueberries are among fruits that are best recognized for their potential health benefits. In red wines, total oligomeric proanthocyanidin content, including catechins, was substantially higher (177.18 +/- 96.06 mg/L) than that in white wines (8.75 +/- 4.53 mg/L). A relative high correlation in red wines was found between ORAC(PE) values and malvidin compounds (r = 0.75, P < 0.10), and proanthocyanidins (r = 0.87, P < 0.05). In white wines, a significant correlation was found between the trimeric proanthocyanidin fraction and peroxyl radical scavenging values (r = 0.86, P < 0.10). A moderate drink (1 drink per day, about 140 mL) of red wine, or white wine, or wine made from highbush blueberry corresponds to an intake of 2.04 +/- 0.81 mmol of TE, 0.47 +/- 0.15 mmol of TE, and 2.42 +/- 0.88 mmol of TE of ORAC(PE)/day, respectively.     

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.     

Relationship among antioxidant activity, vasodilation capacity, and phenolic content of red wines

The relationship among antioxidant activity, based on the electron-spin resonance determination of the reduction of Fremy's radical, vasodilation activity, and phenolic content was investigated in 16 red wines. The wines were selected to provide a range of origins, grape varieties, and vinification methods. Sensitive and selective HPLC methods were used for the analysis of the major phenolics in red wine: free and conjugated myricetin, quercetin, kaempferol, and isorhamnetin; (+)-catechin, (-)-epicatechin, gallic acid, p-coumaric acid, caffeic acid, caftaric acid, trans-resveratrol, cis-resveratrol, and trans-resveratrol glucoside. Total anthocyanins were measured using a colorimetric assay. The total phenolic content of the wines was determined according to the Folin-Ciocalteu colorimetric assay and also by the cumulative measurements obtained by HPLC. The 16 wines exhibited a wide range in the values of all parameters investigated. However, the total phenol contents, measured both by HPLC and colorimetrically, correlated very strongly with the antioxidant activity and vasodilation activity. In addition, the antioxidant activity was associated with gallic acid, total resveratrol, and total catechin. In contrast, only the total anthocyanins were correlated with vasodilation activity. The results demonstrate that the different phenolic profiles of wines can produce varying antioxidant and vasodilatant activities, which opens up the possibility that some red wines may provide enhanced health benefits for the consumer.     

Multivariate analysis of antioxidant power and polyphenolic composition in red wines

It has been demonstrated that the dietary intake of compounds having antioxidant activity is very important, and various chemical, biological, and electrochemical methods have been proposed to evaluate the antioxidant power of compounds such as polyphenols. Wine, although nonessential, has a high polyphenol content up to 2-3 g/L in red wines obtained by traditional maceration. The polyphenol content of wines is usually evaluated by the Folin reagent, which provides an appropriate response to the requirements of wine manufacturers. Because the presence of individual polyphenols may be evaluated by HPLC, more or less selective methods toward the various chemical classes of polyphenols have been developed. An HPLC method set up recently was applied to evaluate how individual polyphenols contributed to the overall antioxidant power (AOP) of 60 Italian red wines, trying to identify the effect that individual compounds may have on the total AOP. Application of the multivariate analysis allowed us to detect some determining compounds such as gallic acid and some flavonols. On the basis of the correlation between two traditional chemical methods, namely the total polyphenol determination by the Folin reagent and the flavanol determination by the condensation reaction with p-(dimethylamino)-cinnamaldehyde, it was shown that the use of these two merely chemical methods is well correlated (r = 0.83 and 0.87) to an AOP evaluation of red wines.     

Effect of addition of commercial grape seed tannins on phenolic composition, chromatic characteristics, and antioxidant activity of red wine

The effect of addition of grape seed tannins on the phenolic composition, chromatic characteristics, and antioxidant activity of red wine was studied. Two highly pure commercial grape seed tannins (GSE100 and GSE300) were selected, and their phenolic compositions were determined. Two types of red wines were made with Castela?o/Tinta Miu?da (3/2, w/w) grapevine varieties by fermentation on skin using two different maceration times, which correspond to the wines rich and poor in polyphenols, respectively. Each of these wines was used for experimentation with the addition of GSE100 and GSE300 before and immediately after alcoholic fermentation. Phenolic composition, chromatic characteristics, and antioxidant activity of the finished red wines were analyzed by HPLC-DAD, CIElab 76 convention, and DPPH radical test, respectively. The results showed that the addition of grape seed tannins had obvious effects of increasing color intensity and antioxidant activity only in the wines poor in polyphenols. Although GSE300 contained much higher amounts of di- and trimer procyanidins and a lower amount of polymeric proanthocyanidins, it provided effects of increasing the color intensity and antioxidant activity of the wines poor in polyphenols similar to those of GSE100. Furthermore, GSE100 released more gallic acid to wines than GSE300, although no gallic acid was detected in GSE100. Tannins added after alcoholic fermentation had a better effect on phenolic composition of red wine than tannins added before alcoholic fermentation.     

Effect of the maceration technique on the relationships between anthocyanin composition and objective color of Syrah wines

The effects of two different vinification techniques, traditional fermentation and carbonic maceration, on the anthocyanin composition and color of young red wines, made with Syrah grapes grown in a warm climate, were compared. Tristimulus colorimetry was applied to study the color of wines during the vinification, and a high-performance liquid chromatography (HPLC) procedure was used for the analysis of anthocyanins. Carbonic maceration led to wines with lower anthocyanin content, mainly monoglucosides, and total phenols. This was related to lighter wines, less saturated, but more colorful (higher chroma C*ab values), and hues hab similar to those of the Syrah wines made by traditional vinification. Thus, the lightness L* had much more influence on the saturation s*uv of the wines obtained by carbonic maceration than the chroma (s*uv = C*uv/L*). From a study of the color-composition relationships using linear and multiple regression, better relationships were found for the wines from traditional vinification, where the chromatic parameters L*, hab, and s*uv could be predicted from the 3-monoglucosides of delphinidin, petunidin, peonidin, and malvidin concentrations (R > 0.9). However, a good prediction of the chroma C*ab from the anthocyanin composition was not possible. On the contrary, C*ab was the best predicted parameter from the anthocyanins monoglucosides (R > 0.9) in the carbonic maceration wines.     

Antioxidant activity of apple peels

Consumption of fruits and vegetables has been shown to be effective in the prevention of chronic diseases. These benefits are often attributed to the high antioxidant content of some plant foods. Apples are commonly eaten and are large contributors of phenolic compounds in European and North American diets. The peels of apples, in particular, are high in phenolics. During applesauce and canned apple manufacture, the antioxidant-rich peels of apples are discarded. To determine if a useful source of antioxidants is being wasted, the phytochemical content, antioxidant activity, and antiproliferative activity of the peels of four varieties of apples (Rome Beauty, Idared, Cortland, and Golden Delicious) commonly used in applesauce production in New York state were investigated. The values of the peels were compared to those of the flesh and flesh + peel components of the apples. Within each variety, the total phenolic and flavonoid contents were highest in the peels, followed by the flesh + peel and the flesh. Idared and Rome Beauty apple peels had the highest total phenolic contents (588.9 +/- 83.2 and 500.2 +/- 13.7 mg of gallic acid equivalents/100 g of peels, respectively). Rome Beauty and Idared peels were also highest in flavonoids (306.1 +/- 6.7 and 303.2 +/- 41.5 mg of catechin equivalents/100 g of peels, respectively). Of the four varieties, Idared apple peels had the most anthocyanins, with 26.8 +/- 6.5 mg of cyanidin 3-glucoside equivalents/100 g of peels. The peels all had significantly higher total antioxidant activities than the flesh + peel and flesh of the apple varieties examined. Idared peels had the greatest antioxidant activity (312.2 +/- 9.8 micromol of vitamin C equivalents/g of peels). Apple peels were also shown to more effectively inhibit the growth of HepG(2) human liver cancer cells than the other apple components. Rome Beauty apple peels showed the most bioactivity, inhibiting cell proliferation by 50% at the low concentration of 12.4 +/- 0.4 mg of peels/mL. The high content of phenolic compounds, antioxidant activity, and antiproliferative activity of apple peels indicate that they may impart health benefits when consumed and should be regarded as a valuable source of antioxidants.     

Antioxidant activity of dietary polyphenols as determined by a modified ferric reducing/antioxidant power assay

Most nonenzymatic antioxidant activity (scavenging of free radicals, inhibition of lipid peroxidation, etc.) is mediated by redox reactions. The antioxidant (AO) activity of polyphenols (PPs), as ferric-reducing power, was determined for the first time using a modified FRAP (ferric reducing/antioxidant power) assay. Reaction was followed for 30 min, and both Fe(II) standards and samples were dissolved in the same solvent to allow comparison. Selected representative PPs included flavonoids (quercetin, rutin, and catechin), resveratrol, tannic acid, and phenolic acids (gallic, caffeic, and ferulic). Carotenoids (beta-carotene and zeaxanthine), ascorbic acid, Trolox, and BHA were included for comparison. Equivalent concentration 1 (EC(1)), as the concentration of AO with a reducing effect equivalent to 1 mmol/L Fe(II), was used to compare AO efficiency. PPs had lower EC(1) values, and therefore higher reducing power, than ascorbic acid and Trolox. Tannic acid and quercetin had the highest AO capacity followed by gallic and caffeic acids. Resveratrol showed the lowest reducing effect. Carotenoids had no ferric reducing ability. Polyphenol's AO efficiency seemed to depend on the extent of hydroxylation and conjugation.     

Electrochemical sensing of total antioxidant capacity and polyphenol content in wine samples using amperometry online-coupled with microdialysis

This work describes the method for total antioxidant capacity (TAC) and/or total content of phenolics (TCP) analysis in wines using microdialysis online-coupled with amperometric detection using a carbon microfiber working electrode. The system was tested on 10 selected wine samples, and the results were compared with total reactive antioxidant potential (TRAP), oxygen radical absorbance capacity (ORAC), and chemiluminescent determination of total antioxidant capacity (CL-TAC) methods using Trolox and catechin as standards. Microdialysis online-coupled with amperometric detection gives similar results to the widely used cyclic voltammetry methodology and closely correlates with ORAC and TRAP. The problem of electrode fouling is overcome by the introduction of an electrochemical cleaning step (1-2 min at the potential of 0 V vs Ag/AgCl). Such a procedure is sufficient to fully regenerate the electrode response for both red and white wine samples as well as catechin/Trolox standards. The appropriate size of microdialysis probes enables easy automation of the electrochemical TAC/TCP measurement using 96-well microtitration plates.     

Chemical composition, antioxidant properties, and thermal stability of a phytochemical enriched oil from Acai (Euterpe oleracea Mart.)

Phenolic compounds present in crude oil extracts from acai fruit ( Euterpe oleracea) were identified for the first time. The stability of acai oil that contained three concentrations of phenolics was evaluated under short- and long-term storage for lipid oxidation and phenolic retention impacting antioxidant capacity. Similar to acai fruit itself, acai oil isolates contained phenolic acids such as vanillic acid (1,616 +/- 94 mg/kg), syringic acid (1,073 +/- 62 mg/kg), p-hydroxybenzoic acid (892 +/- 52 mg/kg), protocatechuic acid (630 +/- 36 mg/kg), and ferulic acid (101 +/- 5.9 mg/kg) at highly enriched concentrations in relation to acai pulp as well as (+)-catechin (66.7 +/- 4.8 mg/kg) and numerous procyanidin oligomers (3,102 +/- 130 mg/kg). Phenolic acids experienced up to 16% loss after 10 weeks of storage at 20 or 30 degrees C and up to 33% loss at 40 degrees C. Procyanidin oligomers degraded more extensively (23% at 20 degrees C, 39% at 30 degrees C, and 74% at 40 degrees C), in both high- and low-phenolic acai oils. The hydrophilic antioxidant capacity of acai oil isolates with the highest phenolic concentration was 21.5 +/- 1.7 micromol Trolox equivalents/g, and the total soluble phenolic content was 1252 +/- 11 mg gallic acid equivalents/kg, and each decreased by up to 30 and 40%, respectively, during long-term storage. The short-term heating stability at 150 and 170 degrees C for up to 20 min exhibited only minor losses (<10%) in phenolics and antioxidant capacity. Because of its high phenolic content, the phytochemical-enriched acai oil from acai fruit offers a promising alternative to traditional tropical oils for food, supplements, and cosmetic applications.     

Isolation of black tea pigments using high-speed countercurrent chromatography and studies on properties of black tea polymers

Isolation of theaflavins and epitheaflavic acids from black tea using high-speed countercurrent chromatography (HSCCC) on a preparative scale is demonstrated. HSCCC also enabled the isolation of a polymeric fraction from black tea. According to Roberts' classification, the polymeric fraction mainly consisted of SII thearubigins (TR). HPLC analysis showed that the isolated material is free of any known chromatographically resolved tea constituents and eluted from reversed-phase packings as a convex "hump" (a broad signal). The antioxidant activity of the TR fraction was 3.6 mmol of Trolox equivalents per gram. The total phenolic content of this fraction was determined to be 34.7 g/100 g (as gallic acid equivalents).     

Phytochemical quantification and total antioxidant capacities of emmer (Triticum dicoccon Schrank) and einkorn (Triticum monococcum L.) wheat landraces

In this study, samples of 18 ancient wheat (12 emmer, 6 einkorn) and 2 bread wheat varieties grown in different regions of Turkey were examined for their total phenolics and flavonoids, phenolic acids, lutein, total yellow pigment, and total radical scavenging capacities against ABTS cation. Results showed that health beneficial phytochemicals and total antioxidant capacities were generally significantly different in emmer and einkorn wheat groups. Remarkably higher total antioxidant activity (18.31 +/- 1.31 micromol Trolox equiv/g), total phenolics (6.33 +/- 0.98 micromol gallic acid equiv/g), ferulic acid (662.95 +/- 61.07 microg/g), and flavonoids (1.61 +/- 0.34 micromol catechin equiv/g) content were detected in emmer wheat samples (n = 12), suggesting that they may have high potential for utilization as a novel grain, rich in natural antioxidants. In addition, quite high levels of lutein (7.33 +/- 2.43 microg/g) of einkorn samples (n = 6) hold the potential of developing high-lutein bakery products to considerably raise the dietary intake of carotenoids. These findings for ancient wheat varieties are considered to be very useful in breeding programs for selecting and breeding wheat varieties for higher concentration and better composition of health-beneficial phytochemicals.     

Direct formulation of a solid foodstuff with phenolic-rich multicomponent solutions from grape seed: effects on composition and antioxidant properties

The aim of our work was to supplement a solid foodstuff with grape phenolics by osmotic treatment with an aqueous solution made of osmo-active agents (NaCl and sucrose) and a commercial grape seed extract. To investigate how the composition of the osmotic solution affected phenolic infusion, experimental conditions were set by a central composite design with two factors (the molality of NaCl and sucrose in the osmotic solution). In all experiments, the total phenolic content in the osmotic solution was kept constant (6300 +/- 45 mg gallic acid equivalents/kg), and the model food (an agar-agar gel) was processed for 8 h. Throughout the response surface, the osmo-treated model food was significantly supplemented with flavan-3-ols. At the central point of the experimental design, flavan-3-ol monomers and dimers were found in concentrations of 1334 +/- 126 and 486 +/- 55 mg/kg, respectively. Their penetration into the model food was limited by sucrose to a different extent. The Trolox equivalent antioxidant capacity of the osmo-treated gel was higher than that of fruits with a very high free radical scavenging activity.     

Importance of insoluble-bound phenolics to antioxidant properties of wheat

Two commercial samples of soft (70% Canadian Eastern soft red spring and 30% Canadian Eastern soft white winter) and hard (90% Canadian western hard red spring and 10% Canadian Eastern hard red winter) wheats were used to obtain different milling fractions. Phenolics extracted belonged to free, soluble esters and insoluble-bound fractions. Soluble esters of phenolics and insoluble-bound phenolics were extracted into diethyl ether after alkaline hydrolysis of samples. The content of phenolics was determined using Folin-Ciocalteu's reagent and expressed as ferulic acid equivalents (FAE). The antioxidant activity of phenolic fractions was evaluated using Trolox equivalent antioxidant capacity, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, reducing power, oxygen radical absorbance capacity, inhibition of oxidation of human low-density lipoprotein cholesterol and DNA, Rancimat, inhibition of photochemilumenescence, and iron(II) chelation activity. The bound phenolic content in the bran fraction was 11.3 +/- 0.13 and 12.2 +/- 0.15 mg FAE/g defatted material for hard and soft wheats, respectively. The corresponding values for flour were 0.33 +/- 0.01 and 0.46 +/- 0.02 mg FAE/g defatted sample. The bound phenolic content of hard and soft whole wheats was 2.1 (+/-0.004 or +/-0.005) mg FAE/g defatted material. The free phenolic content ranged from 0.14 +/- 0.004 to 0.98 +/- 0.05 mg FAE/g defatted milling fractions of hard and soft wheats examined. The contribution of bound phenolics to the total phenolic content was significantly higher than that of free and esterified fractions. In wheat, phenolic compounds were concentrated mainly in the bran tissues. In the numerous in vitro antioxidant assays carried out, the bound phenolic fraction demonstrated a significantly higher antioxidant capacity than free and esterified phenolics. Thus, inclusion of bound phenolics in studies related to quantification and antioxidant activity evaluation of grains and cereals is essential.