Phenolic acid profiles and antioxidant activities of wheat bran extracts and the effect of hydrolysis conditions

Four different types of wheat bran were extracted and analyzed for phenolic acids using the Folin–Ciocalteu method and HPLC. The extracts and their hydrolysis products were also evaluated for their antioxidant activities. The total phenolic content of the red wheat bran was higher than that of the white wheat. We found that the majority of the phenolic acids existed in a bound form in wheat bran. These phenolic acids can be released by hydrolyzing the bran under alkaline or acidic conditions; however, the former was more efficient in the release of free phenolic acids than the latter. Ferulic, vanillic, and syringic acids were the major individual phenolic acids in the studied wheat bran. The main portion of the total ferulic acid was from alkaline hydrolysis. The alkaline hydrolysable fractions had greater antioxidant activities, while the acid hydrolysable fractions showed lower activities in both the red and white bran. The antioxidant activity of bran extract was stronger than that of free phenolic acids.     

Phenolic acid composition of sprouted wheats by ultra-performance liquid chromatography (UPLC) and their antioxidant activities

The phenolic acid profiles of flours from two Canadian wheat classes, Canadian Western Red Spring (CWRS) and Canadian Western Amber Durum (CWAD), were investigated using two different extraction mediums and analysed on an ultra-performance liquid chromatography (UPLC) system at different degrees of sprout damage. A sound (non-sprouted) control sample as well as two different sprouted sub-samples, derived from different germination protocols of the control, were prepared for both the CWAD and CWRS. Free phenolic acids were extracted from the ground whole wheat meal using three repetitive 80% ethanol extractions. Bound phenolic compounds were subsequently released from the residue by alkaline hydrolysis followed by triplicate extraction with diethyl ether:ethyl acetate (1:1, v/v). Twelve phenolic acid standards were clearly resolved and quantified using a short 5 min elution gradient. Seven phenolic acids (4-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, ferulic and sinapic) were detected in the CWRS and CWAD alcoholic and alkaline extracts. Syringic acid was the main compound in the free phenolic alcoholic extracts of the wheat meal representing 77.0% and 75.3% of the total amount of detected free phenolic compounds for CWRS and CWAD, respectively. However, the major released phenolic compound detected in the alkaline hydrolysed extracts was ferulic acid accounting for 72.3% and 71.0% for CWRS and CWAD respectively total bound phenolics. During germination, syringic acid levels rose as the length of germination time increased, resulting in the increase in total phenolic compound and antioxidant activity of the sprouted wheat flours. There was an increase in total phenolic compounds and the antioxidant activity of the alcoholic extracts from the CWRS and CWAD wheat flours as the germination time was extended. As a result, the sprouted wheats exhibits better nutritional properties than un-germinated wheat and could be used to improve the nutrition value in food products.     

Phenolic Profiles and Total Antioxidant Capacity of Marketed Beers in Serbia

The aim of this research was to determine the total phenolic and flavonoid contents as well as to measure antioxidant activity of 24 different commercial beers consumed in Serbia. The major phenolic acids (gallic acid, protocatechuic acid, 4-hydroxybenzoic acid, 2,5-dihydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, sinapic acid, salicylic), (+)-catechin, and (-)-epicatechin were also determined by high pressure liquid chromatography method using a photodiode array detector. Gallic acid, ferulic acid, and protocatechuic acid are the most abundant phenolic acids in all samples, followed by (+)-catechin. The total phenolic content was determined using the Folin-Ciocalteu assay. The total flavonoids were measured using spectrophotometrics as the aluminum chloride assay. The results showed that the highest total phenolic and flavonoid contents were established in dark and light beer samples. 2,2-Diphenyl-1-picrylhidrazyl radical scavenging activity, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical cation scavenging activity, and ferric reducing/antioxidant power were used to assess the antioxidant potential of beers. These assays, based on different chemical mechanisms, were selected to take into account the wide variety and range of action of antioxidant compounds present in selected beer samples. All beers showed antioxidant power, but a wide range of antioxidant capacities was observed. Statistical differences between ferric reducing-antioxidant power and the other two antioxidant capacity assays were confirmed. This study will be useful for the appraisal of phenolic profile and antioxidant activities of various beers, and it will also be of interest for people who like drinking this beverage.     

Comparison of total antioxidant capacity and phenolic composition of some apple juices with combined HPLC–CUPRAC assay

It was aimed in this study to identify and quantify various constituents (particularly phenolics) of apple juice and to quantitatively compare the total antioxidant capacities of juices obtained from apple varieties grown in Turkey.     

蒸汽爆破处理对麦麸的酚酸组成及其抗氧化活性的影响

该试验旨在研究蒸汽爆破处理对小麦麸皮的酚酸组成及抗氧化活性的影响。将麦麸在不同处理压力(0.5,1.5,2.5 MPa)和不同处理时间(30,90 s)条件下进行蒸汽爆破预处理。通过水解和碱提的方法,将得到的麦麸进行提取,得到游离酚酸和结合酚酸 2部分,对其中的几种主要酚酸,如香草酸、丁香酸, 4-香豆酸,阿魏酸进行研究。结果表明, 4种主要酚酸的含量在蒸汽爆破处理后均有所提高,其中阿魏酸的含量最高,结合酚酸中由未处理时的 57.232 μg/g提高到了 1454.092 μg/g。该试验还进行了总酚测定,抗氧化活性的测定。通过总酚的测定可以看出,蒸汽爆破处理后,总酚的含量高于未处理麦麸,且随着处理强度的增加,呈现先增加后减少的趋势,在处理条件为 2.5 MPa,30 s,总酚含量最高,约为未处理时的 9倍。抗氧化试验得到的变化趋势与总酚呈现相似的规律,与未进行蒸汽爆破预处理的麦麸相比,处理后的麦麸表现出了更高的 1,1-二苯基 -2-三硝基苯肼(DPPH)和 2,2-联氮 -二(3-乙基 -苯并噻唑 6-磺酸)二铵盐(ABTS)自由基清除率,以及在亚油酸体系中的抗氧化活性和还原能力。当处理条件为 2.5 MPa,30 s时,抗氧化活性表现最高。由此可得到, 2.5 MPa 30 s是蒸汽爆破处理麦麸的最佳条件,此时麦麸中酚酸含量和抗氧化活性均较优,为以后麦麸中酚类物质的深度开发利用提供理论支持。     

蒸汽爆破处理对麦麸的酚酸组成及其抗氧化活性的影响

该试验旨在研究蒸汽爆破处理对小麦麸皮的酚酸组成及抗氧化活性的影响。将麦麸在不同处理压力(0.5,1.5,2.5 MPa)和不同处理时间(30,90 s)条件下进行蒸汽爆破预处理。通过水解和碱提的方法,将得到的麦麸进行提取,得到游离酚酸和结合酚酸 2部分,对其中的几种主要酚酸,如香草酸、丁香酸, 4-香豆酸,阿魏酸进行研究。结果表明, 4种主要酚酸的含量在蒸汽爆破处理后均有所提高,其中阿魏酸的含量最高,结合酚酸中由未处理时的 57.232 μg/g提高到了 1454.092 μg/g。该试验还进行了总酚测定,抗氧化活性的测定。通过总酚的测定可以看出,蒸汽爆破处理后,总酚的含量高于未处理麦麸,且随着处理强度的增加,呈现先增加后减少的趋势,在处理条件为 2.5 MPa,30 s,总酚含量最高,约为未处理时的 9倍。抗氧化试验得到的变化趋势与总酚呈现相似的规律,与未进行蒸汽爆破预处理的麦麸相比,处理后的麦麸表现出了更高的 1,1-二苯基 -2-三硝基苯肼(DPPH)和 2,2-联氮 -二(3-乙基 -苯并噻唑 6-磺酸)二铵盐(ABTS)自由基清除率,以及在亚油酸体系中的抗氧化活性和还原能力。当处理条件为 2.5 MPa,30 s时,抗氧化活性表现最高。由此可得到, 2.5 MPa 30 s是蒸汽爆破处理麦麸的最佳条件,此时麦麸中酚酸含量和抗氧化活性均较优,为以后麦麸中酚类物质的深度开发利用提供理论支持。     

蒸汽爆破处理对麦麸的酚酸组成及其抗氧化活性的影响

该试验旨在研究蒸汽爆破处理对小麦麸皮的酚酸组成及抗氧化活性的影响。将麦麸在不同处理压力(0.5,1.5,2.5 MPa)和不同处理时间(30,90 s)条件下进行蒸汽爆破预处理。通过水解和碱提的方法,将得到的麦麸进行提取,得到游离酚酸和结合酚酸 2部分,对其中的几种主要酚酸,如香草酸、丁香酸, 4-香豆酸,阿魏酸进行研究。结果表明, 4种主要酚酸的含量在蒸汽爆破处理后均有所提高,其中阿魏酸的含量最高,结合酚酸中由未处理时的 57.232 μg/g提高到了 1454.092 μg/g。该试验还进行了总酚测定,抗氧化活性的测定。通过总酚的测定可以看出,蒸汽爆破处理后,总酚的含量高于未处理麦麸,且随着处理强度的增加,呈现先增加后减少的趋势,在处理条件为 2.5 MPa,30 s,总酚含量最高,约为未处理时的 9倍。抗氧化试验得到的变化趋势与总酚呈现相似的规律,与未进行蒸汽爆破预处理的麦麸相比,处理后的麦麸表现出了更高的 1,1-二苯基 -2-三硝基苯肼(DPPH)和 2,2-联氮 -二(3-乙基 -苯并噻唑 6-磺酸)二铵盐(ABTS)自由基清除率,以及在亚油酸体系中的抗氧化活性和还原能力。当处理条件为 2.5 MPa,30 s时,抗氧化活性表现最高。由此可得到, 2.5 MPa 30 s是蒸汽爆破处理麦麸的最佳条件,此时麦麸中酚酸含量和抗氧化活性均较优,为以后麦麸中酚类物质的深度开发利用提供理论支持。     

蒸汽爆破处理对麦麸的酚酸组成及其抗氧化活性的影响

该试验旨在研究蒸汽爆破处理对小麦麸皮的酚酸组成及抗氧化活性的影响。将麦麸在不同处理压力(0.5,1.5,2.5 MPa)和不同处理时间(30,90 s)条件下进行蒸汽爆破预处理。通过水解和碱提的方法,将得到的麦麸进行提取,得到游离酚酸和结合酚酸 2部分,对其中的几种主要酚酸,如香草酸、丁香酸, 4-香豆酸,阿魏酸进行研究。结果表明, 4种主要酚酸的含量在蒸汽爆破处理后均有所提高,其中阿魏酸的含量最高,结合酚酸中由未处理时的 57.232 μg/g提高到了 1454.092 μg/g。该试验还进行了总酚测定,抗氧化活性的测定。通过总酚的测定可以看出,蒸汽爆破处理后,总酚的含量高于未处理麦麸,且随着处理强度的增加,呈现先增加后减少的趋势,在处理条件为 2.5 MPa,30 s,总酚含量最高,约为未处理时的 9倍。抗氧化试验得到的变化趋势与总酚呈现相似的规律,与未进行蒸汽爆破预处理的麦麸相比,处理后的麦麸表现出了更高的 1,1-二苯基 -2-三硝基苯肼(DPPH)和 2,2-联氮 -二(3-乙基 -苯并噻唑 6-磺酸)二铵盐(ABTS)自由基清除率,以及在亚油酸体系中的抗氧化活性和还原能力。当处理条件为 2.5 MPa,30 s时,抗氧化活性表现最高。由此可得到, 2.5 MPa 30 s是蒸汽爆破处理麦麸的最佳条件,此时麦麸中酚酸含量和抗氧化活性均较优,为以后麦麸中酚类物质的深度开发利用提供理论支持。     

蔬菜抗氧化能力及与酚酸和总黄酮相关性研究

分析常见蔬菜总抗氧化活性,探讨蔬菜抗氧化能力与酚酸、总黄酮的相关性。采用ABTS、DPPH与FRAP法测定10种常见蔬菜的抗氧化能力,采用Folin-Ciocalteu法测总酚酸,硝酸铝-亚硝酸钠-氢氧化钠法测总黄酮,采用matlab软件进行拟合抗氧化与酚酸、总黄酮的函数方程。结果表明:抗氧化活性与主要抗氧化物质(酚酸和黄酮)的函数关系为Z=-137.743 2-0.918 2 X2+0.211 2Y2-0.422 9 XY+52.843 5 X+2.229 9Y。当总黄酮在6～26mg/100g时,总黄酮、酚酸的量对总抗氧化活性有促进作用;而在27～54mg/100g范围内,总黄酮和酚酸的含量对总抗氧化能力具有一定的抑制作用。     

Antioxidant activity and dietary fibre in durum wheat bran by-products

Milling of wheat generates by-products, which can be used to improve the technological performance and/or to integrate foods with healthy compounds. The aim of this paper was to select fractions of durum wheat bran having different functional and nutritional characteristics. Wheat bran by-products were obtained by an industrial milling process. Beside the single fractions, two commercial products Bran & Brain 50 and 70, obtained by blending some of the durum wheat fractions were also studied. All samples were investigated for water holding capacity, soluble and insoluble dietary fibre content and for their antioxidant activity. The soluble fibre content of the durum wheat by-product ranged between 0.9% and 4.1%; while that of insoluble fibre between 21% and 64%. B&B 70 has a TDF content of 61%, while B&B 50 has 42%. The water holding capacity of each fraction is strictly related to the amount of insoluble fibre and to the granulometry of the by-products. Cooking-extrusion process does not affect the amount of soluble fibre; by contrast, a significant increase of the insoluble fibre was detected. The antioxidant activity is higher for the internal bran fraction and it increases in fractions having reduced granulometry. The antioxidant activity of some durum wheat by-product fractions is comparable to that of widespread fruits and fresh vegetables, likely due to the presence of fibre-bound phenol compounds. The high fibre content and antioxidant activity of durum wheat bran by-products can be of particular interest for their use in cereal-based products.     

Phenolic content and antioxidant activity of eight representative sweet corn varieties grown in South China

In the present study, phenolic content and antioxidant capacities including cellular antioxidant activity of eight Chinese sweet corn varieties were investigated. The total phenolic content revealed significant varietal differences and phenolics existed mainly in free form. HPLC analysis showed that ferulic and p-coumaric acids were the dominating phenolics in sweet corn. The DPPH scavenging capacity, ferric reducing antioxidant power, and cellular antioxidant activity demonstrated distinct varietal differences, which were positively correlated with their phenolic content, although the orders of antioxidant activity of eight varieties determined by three different methods were not consistent. Sweet corn could be a better substitute for many commonly consumed vegetables in terms of phenolics and antioxidant activity.     

Antioxidant and Free Radical Scavenging Activities of Indian Acacias: Acacia Leucophloea (Roxb.) Willd., Acacia Ferruginea Dc., Acacia Dealbata Link. and Acacia Pennata (L.) Willd

The acetone and methanol extracts of barks of A. leucophloea, A. ferruginea, A. dealbata, and A. pennata were evaluated for their total phenolics and flavonoid contents and antioxidative activities. Acetone extracts of barks exhibited higher contents of total phenolics and flavonoids. Further, the acetone extracts showed higher activity in DPPH^?, ABTS^?+, and OH^?; FRAP; metal chelation; phosphomolybdenum reduction; and peroxidation inhibition. In conclusion, the results implied that the barks could be considered as health supplements and nutraceuticals/functional foods.     

Phenolic content and antioxidant capacity of supercritical carbon dioxide-treated and air-classified oat bran concentrate microwave-irradiated in water or ethanol at varying temperatures

Oat bran concentrate (OBC) was defatted with supercritical carbon dioxide (SCD), then microwave-irradiated (MI) at 50, 100 or 150 °C for 10 min in water, 50% or 100% ethanol, and extract pH, soluble solids, phenolic content (PC) and antioxidant capacity (AC) were analysed. OBC was air-classified into five fractions and MI in water at 150 °C. OBC without SCD and microwave irradiation was extracted at 22 °C. Most effective temperature during microwave irradiation for maximising extraction of PC and AC was 150 °C. Defatted OBC in 50% ethanol and MI at 150 °C extracted greatest PC and AC. SCD treatment slightly reduced PC and AC. OBC extracted in water or 50% ethanol at 22 °C without microwave irradiation had similar PC and AC than OBC MI at 150 °C, but much higher levels were observed for latter heat treatment using absolute ethanol. Air-classification shows potential to enhance PC and AC.     

Phenolic Profile and Antioxidant Activity of Polish Meads

The purpose of this study was to evaluate phenolic profile and antioxidant activity of ten different meads of 1:1 and 1:2 types, produced with addition of fruit juices, root spices, and herbs. The total phenolic content in meads varied from 15.27 to 70.80 mg/dm³. The meads originated from dark honeys exhibited the highest antioxidant activity. The predominant phenolic compounds in meads were hydroxybenzoic acids, especially gallic and protocatechuic acid, originated mainly from honeys. Whereas, among the hydroxycinnamic acids, the major phenolic was chlorogenic acid, derived mainly from plant additives used in meads production. A principal component analysis was applied in order to differentiate the investigated meads. The 1:2 meads type could be best described by chlorogenic acid. Among the 1:1 meads type, those made from the dark honeys could be best described by gallic, p-coumaric, and protocatechuic acid while those made with addition of blackcurrant and raspberry juice could be described by caffeic and ferulic acid.     

Effect of processing and cooking on phenolic acid profile and antioxidant capacity of durum wheat pasta enriched with debranning fractions of wheat

The effect of processing and cooking on phenolic acids profile and antioxidant properties of durum wheat (Triticum turgidum L. var. durum) pasta samples enriched with debranning fractions of an Italian wheat (Triticum aestivum L.) cultivar were studied.     

Phytochemical content and antioxidant activity of six diverse varieties of whole wheat

The phytochemical content and antioxidant activity of six diverse varieties of whole wheat are reported. The free phenolic content ranged from 255 (KanQueen) to 499 (Roane) μmol gallic acid equivalents/100 g DW. The bound phenolic content ranged from 582 (Roane) to 662 (Cham1) μmol gallic acid equivalents/100 g DW. The bound fraction contributed 53.8–69.7% of the total phenolic content of the wheat varieties analysed. Ferulic acid was the predominant phenolic acid found in whole wheat. Total ferulic acid content ranged from 310.8 (Caledonia) to 496.1 (KanQueen) μmol ferulic acid/100 g DW. The percentage of ferulic acid found in the insoluble-bound fraction ranged from 87.4% (Caledonia) to 97.2% (KanQueen). Other phenolic acids, p-coumaric acid, syringic acid, vanillic acid, and caffeic acid were also detected. Lutein was the predominant carotenoid found in the whole wheat varieties analysed. Zeaxanthin, β-carotene, and β-cryptoxanthin were also detected. Mainly α- and β-tocopherols and α- and β-tocotrienols were found in all varieties of whole wheat though γ-tocopherol was detected in all but two varieties. β-Tocotrienol was the predominant form of vitamin E found in all varieties of whole wheat. The antioxidant activity was assessed using the oxygen radical absorbance capacity (ORAC) assay. The ORAC of the free fraction ranged from 1958 to 3749 μmol Trolox equivalents/100 g DW. The ORAC of the bound fraction ranged from 3190 to 5945 μmol Trolox equivalents/100 g DW. Total phenolic content was correlated with oxygen radical absorbance capacity (R² = 0.810; p < 0.001). The phytochemicals found in whole grains may be responsible for the health benefit of whole grain consumption.     

Phenol content,antioxidant activity and metal composition of Croatian wines deriving from organically and conventionally grown grapes

The present study was performed to evaluate the antioxidant capacity, the polyphenol and metal content of conventionally and organically produced wines, which underwent similar winemaking processes. The wine grapes were grown under well-defined organic and conventional conditions from the two different wine-growing sub-regions of Croatia, Prigorje and Southern Dalmatia. The values of antioxidant activity, as evaluated by two free radical methods, ABTS and DPPH, was found systematically higher in organic wines compared to conventional ones. In a reversed phase HPLC analysis, used in order to characterise the phenol fraction of wines, higher concentrations of chlorogenic acid, ferulic acid, catechin, trans-resveratrol, all studied hydroxybenzoic acids and flavonols were found in the organically produced wines. No apparent trend was found in the metal contents of the wines, but ICP-MS analysis confirmed that both wine productions, organic and conventional, were well within the toxicological safety limits.     

Phenolic acid analysis and antioxidant activity assessment of oil palm (E. guineensis) fruit extracts

Phenolic compounds in oil palm fruit (E. guineensis) were extracted in soluble free (SFP), insoluble-bound (ISBP) and esterified (EFP) forms. The total phenolic content (TPC) of the oil palm fruit extracts was determined using the Folin–Ciocalteu method and found to range from 5.03 to 9.04 g/L per g of dried weight (DW). The antioxidant activities of oil palm phenolic extracts were analysed using free radical scavenging assays and results showed that oil palm phenolic extracts contained antioxidant activities in the order of ISBP > EFP > SFP. Eight different phenolic acids were identified and quantified using a simple reversed-phase high performance liquid chromatography (HPLC) with a diode array detector (DAD) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). Ferulic, p-hydroxybenzoic and p-coumaric acid were the dominant phenolic acids found in oil palm fruit extracts and ranged from 55 to 376 μg/g of DW.     

Effect of thermal processing on antioxidant properties of purple wheat bran

Antioxidant activity of purple wheat bran, heat-treated purple wheat bran, and purple wheat bran muffins was evaluated to determine the impact of thermal processing on potential health benefits. The purple wheat bran and muffin samples were analyzed for total phenolic content, anthocyanin content and free radical scavenging activity using peroxyl (oxygen radical absorbance capacity assay) and 2,2-diphenyl-1-picrylhydrazyl (DPPH assay) radicals. Total phenolic content and oxygen radical absorbance capacity (ORAC) values of sample extracts were significantly affected by various extracting solvents. The conditions selected for heat treatment did not markedly change antioxidant activity of purple wheat bran. However, there was a significant reduction in total phenolic contents, ORAC values and total anthocyanins during processing of purple wheat bran- or heat-treated purple wheat bran-enriched muffins. On the contrary, muffin extracts still remained excellent in DPPH radical scavenging activity.