Antioxidant and free radical scavenging activities of whole wheat and milling fractions

The effects of milling on the phenolic content and antioxidant capacity of two wheat cultivars, namely CWAD (Canadian Western Amber Durum; Triticum turgidum L. var. durum) and CWRS (Canadian Western hard red spring; Triticum aestivum L.) were studied. The milling of wheat afforded several fractions, namely bran, flour, shorts and feed flour. In addition, semolina was the end-product of durum wheat milling. Among different milling fractions the bran had the highest phenolic content while the endosperm possessed the lowest amount and this was also reflected in free radical and reactive oxygen species (ROS) scavenging capacity, reducing power and iron (II) chelation capacity of different milling fractions in the two cultivars. This study demonstrated the importance of bran in the antioxidant activity of wheat, hence consumption of whole wheat grain may render beneficial health effects.     

Effect of ultrafine grinding on hydration and antioxidant properties of wheat bran dietary fiber

Wheat bran dietary fiber (DF) powders was prepared by ultrafine grinding, whose effects were investigated on the composition, hydration and antioxidant properties of the wheat bran DF products. The results showed that ultrafine grinding could effectively pulverize the fiber particles to submicron scale. As particle size decrease, the hydration properties (water holding capacity, water retention capacity and swelling capacity) of wheat bran DF were significantly (p < 0.05) decreased and a redistribution of fiber components from insoluble to soluble fractions was observed. The antioxidant activities of wheat bran and DF before and after grinding were in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferrous ion-chelating activity, reducing power and total phenolic content (TPC). Compared with DF before and after grinding, micronized insoluble DF showed increased chelating activity, reducing power and TPC yet decreased DPPH˙ radical scavenging activity. Positive correlations were detected between chelating activity, reducing power and TPC.     

植物油的不同组分DPPH自由基清除能力及其与微量有益成分含量的相关性

研究评估13种常见植物油的极性组分、非极性组分和全油样品的DPPH自由基清除能力,并将DPPH自由基清除能力与生育酚、多酚、植物甾醇等微量有益成分含量进行相关性分析。结果表明:橄榄油、芝麻油、小麦胚芽油和米糠油极性组分的DPPH自由基清除能力高于其他植物油,均大于200μmol TE/100 g;植物油非极性组分的DPPH自由基清除能力在10.53~553.20μmol TE/100 g之间,小麦胚芽油和米糠油的清除能力较高;植物油全油的DPPH自由基清除效果比非极性组分的略高;植物油非极性组分、植物油全油的DPPH自由基清除能力与生育酚含量、β-谷甾醇含量、菜油甾醇含量呈显著相关(P0.01);植物油极性组分的DPPH自由基清除能力则与多酚含量呈显著相关(P0.05)。     

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.     

Isolation and Identification of Phenolic Antioxidants in Black Rice Bran

Black rice bran contains phenolic compounds of a high antioxidant activity. In this study, the 40% acetone extract of black rice bran was sequentially fractionated to obtain 5 fractions. Out of the 5 fractions, ethyl acetate fraction was subfractionated using the Sephadex LH‐20 chromatography. The antioxidant activity of phenolic compounds in the extracts was investigated by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical assay, 2,2‐azino‐bis‐(3‐ethylenebenzothiozoline‐6‐sulfonic acid) (ABTS) radical cation assay, reducing power. The subfraction 2 from ethyl acetate fraction had the highest total phenolic contents (TPC) (816.0 μg/mg) and the lowest EC₅₀ values (47.8 μg/mL for DPPH radical assay, 112.8 μg/mL for ABTS radical cation assay, and 49.2 μg/mL for reducing power). These results were 3.1, 1.3, and 2.6 times lower than those of butylated hydroxytoluene (BHT), respectively. At a concentration of 100 μg/mL, the antioxidant activity and TPC of various extracts was closely correlated, with correlation coefficients (R²) higher than 0.86. The major phenolic acid in subfraction 2 was identified as ferulic acid (178.3 μg/mg) by HPLC and LC‐ESI/MS/MS analyses. Our finding identified ferulic acid as a major phenolic compound in black rice bran, and supports the potential use of black rice bran as a natural source of antioxidant.     

Extractability of antioxidants from legume seed flour after cooking and in vitro gastrointestinal digestion in comparison with methanolic extraction of the unprocessed flour

Antioxidant activities were studied in methanolic and water extracts of nonprocessed, cooked and in vitro enzymatically digested seed flour, as well as in total protein hydrolysates and small peptide fractions (<3 and <10 kDa) of three pea and five grass pea cultivars. The antioxidative properties were determined by three spectrophotometric methods: 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging assay, Folin‐Ciocalteu (FC) reducing capacity assay and H₂O₂ scavenging. We also applied one luminometric assay for hydroxyl radical scavenging. The study showed that cooking and enzymatic digestion strongly enhanced the release of phenolic compounds in methanolic extracts of four analysed cultivars. Scavenging activity against DPPH radical, hydroxyl radical and hydrogen peroxide was increased in majority of analysed flour specimens subjected to processing. Our findings indicate that, besides the phenolic compounds, the small peptide fraction, especially the MW <3 kDa, in methanolic and aqueous extracts of cooked and digested seed flour significantly contribute to free radical and hydrogen peroxide scavenging activity in all investigated cultivars. Our data strongly suggest that simple cooking treatment and in vitro digestion of seed flour applied prior to extraction with methanol could improve antioxidative activity of obtained extracts.     

Evaluation of Wheat Bran Obtained by Tangential Abrasive Dehulling Device

A tangential abrasive dehulling device (TADD) was used to evaluate debranning properties of wheat grain and obtain grain fractions enriched in antioxidants. Effect of grain moisture content and abrasion time on the chemical composition and antioxidant capacity of the fractions were examined. Whole wheat, bran from a quadrumat senior mill, and a commercial aleurone sample were used as references. Total phenolic content (TPC), oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity of the TADD bran extracts were determined and compared to those of the reference materials and butylated hydroxytoluene (BHT). TADD bran fraction obtained at original grain moisture level, 11%, and short abrasion time, 1 min, had the highest ORAC value among the samples examined in this study. Only the sample obtained at 11% moisture level and 1 min abrasion time had similar ORAC, TPC, and DPPH values that are similar to those of the commercial aleurone despite the big difference in their starch content. The effect of grain moisture, abrasion time, and moisture?×?abrasion time interaction had significant effects on the chemical composition and antioxidant capacity of the fractions. This study demonstrated that TADD was very effective in producing wheat grain fractions with high antioxidant content.     

Inhibitory effect of Chardonnay and black raspberry seed extracts on lipid oxidation in fish oil and their radical scavenging and antimicrobial properties

Ethanol extracts of Chardonnay grape and black raspberry seed flours were evaluated for their capacity to suppress lipid oxidation, preserve important fatty acids, and inhibit microbial growth. They were also tested for radical scavenging activity against DPPH and peroxyl radicals as reflected in oxygen radical absorbance capacity (ORAC), and total phenolic content (TPC). Both tested seed flour extracts suppressed lipid oxidation and rancidity development in fish oil. Black raspberry seed flour extract significantly reduced the degradation of biologically important n − 3 PUFA under accelerated oxidative conditions. Black raspberry and Chardonnay seed flour extracts at 165 and 160 μg seed flour equivalents/mL, respectively exhibited bacteriocidal activity against Escherichia coli and growth inhibition of Listeria monocytogenes under experimental conditions. Both seed flour extracts exhibited DPPH radical quenching activity and Chardonnay had the stronger ORAC of 663 μmol Trolox equivalents per gram seed flour and the higher TPC of 99 mg gallic acid equivalents/g flour. The data from this study suggest the potential for developing natural food preservatives from these seed flours for improving food stability, quality, safety, and consumer acceptance.     

丝瓜花不同溶剂提取物抗氧化活性及其酚类成分分析

以无水乙醇、70%乙醇、40%乙醇和水分别对丝瓜花进行提取,并测定各提取物中总酚、总黄酮含量,采用DPPH·清除能力、超氧化物自由基清除能力、FRAP抗氧化能力和亚铁离子螯合能力等方法评价其抗氧化活性,通过HPLC分析其中酚类成分。结果表明,70%和40%乙醇提取物总酚及总黄酮含量较高,而且DPPH·清除活性、FRAP还原力最强,40%乙醇提取物、水提物分别具有最强的超氧阴离子自由基清除活性和亚铁离子螯合能力。总酚含量与DPPH·清除活性之间存在较强的相关性(R²=0.8688)。HPLC分析检出提取物中9种酚类化合物,其中含量最高的为杨梅素。试验结果说明,70%乙醇、40%乙醇可能是丝瓜花抗氧化性物质提取的较好溶剂。结果表明丝瓜花是一种较好的抗氧剂资源。     

小麦麸皮总黄酮清除DPPH自由基活性的研究

以小麦麸皮为原料,乙醇为提取溶剂,超声波辅助提取总黄酮。考察了12种大孔吸附树脂对没食子酸的吸附量,选用LSA-21大孔吸附树脂对小麦麸皮总黄酮进行吸附,60%乙醇溶液解吸。分别考察了不同浓度的Vc、小麦麸皮总黄酮粗提物和纯化物对1,1-二苯基-2-苦苯肼自由基(DPPH·)的清除效果。结果表明:LSA-21大孔吸附树脂对没食子酸的吸附能力较强,吸附量达0.21 mg/g。Vc、小麦麸皮总黄酮粗提物和纯化物对DPPH·均有清除作用,其清除能力大小顺序为:小麦麸皮总黄酮纯化物小麦麸皮总黄酮粗提物Vc。     

Phytochemical compositions, and antioxidant properties, and antiproliferative activities of wheat flour

Ten soft wheat varieties grown in Maryland were compared for their phytochemical compositions, antioxidant properties and antiproliferative activities. Free radical scavenging capacities were examined against DPPH(·), oxygen, hydroxyl and ABTS(·+) radicals. Significant radical scavenging capacities were detected in all wheat flour extracts. Total phenolic content ranged from 1.66 to 2.01 mg of GAE/g wheat flour. The wheat flours contained 172.91-297.55 μg/g insoluble bound ferulic acid, contributing 89.74-94.29% of total ferulic acid on a per weight basis. The concentrations of lutein and zeaxanthin were 0.27-0.46 and 0.08-0.13 μg/g, respectively. In addition, the wheat flours had 0.30-0.59 and 0.07-0.29 μg/g α- and δ-tocopherols, respectively. Four wheat flour extracts were further examined for their antiproliferative activities. The Jamestown wheat flour showed significant antiproliferative activity against both HT-29 and Caco-2 colon cancer cells at the initial treatment concentration of 50 mg flour equivalents/ml, while USG3555 flour showed inhibitive effect only in HT-29 cancer cells, suggesting the different and possible selective antiproliferative property of the wheat flours. These results may be used to direct the breeding effects to produce soft winter wheat varieties with improved health properties.     

Total phenolic content and antioxidant capacity of extracts obtained from six important fruit residues

The extracts from kinnow peel, kinnow seeds, litchi pericarp, litchi seeds, grape seeds, and banana peel were screened for total phenolic content (TPC), trolox equivalent antioxidant capacity (TEAC), 1,1 diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, as well as reducing power. Kinnow peel extract exhibited the highest reducing power, TEAC, and DPPH free radical scavenging activity, whereas, the phenolic content of 37.4 mg GAE/g-dw was highest for grape seed extract. Banana peel extract with a low TPC showed the lowest reducing power, TEAC as well as DPPH free radical scavenging activity among the fruit residue extracts examined in the present study. Correlation analysis between the reducing power and DPPH radical scavenging ability; reducing power and ABTS radical scavenging activity; and ABTS and DPPH radical scavenging abilities showed a high degree of correlation (r² = 0.85-0.91). However, r² of 0.36, 0.66, and 0.49 between TPC and DPPH radical scavenging activity; TPC and reducing power; and TPC and ABTS radical scavenging ability, respectively, indicated that some non-phenolic compounds also contributed to the total antioxidant activity in fruit residue extracts examined in this study. To the best of our knowledge, this is the first paper presenting comprehensive data on TPC, reducing power, and antioxidant activity for the six fruit residues. This study demonstrated that kinnow peel, litchi pericarp, litchi seeds, and grape seeds, can serve as potential sources of antioxidants for use in food and pharmaceutical industry.     

麦胚对高盐稀态酱油理化特性及抗氧化活性的影响

以大豆、面粉及麦胚为原料制备高盐稀态酱油,探究麦胚添加量对酱油各理化指标及抗氧化活性的影响;采用二苯基苦基苯肼（1,1-diphenyl-2-picryhydrazyl,DPPH）自由基清除法、2,2’-联氮-二（3-乙基-苯并噻唑-6-磺酸）二铵盐（3-ethylbenzthiazoline-6-sulphonate,ABTS）自由基清除法、还原力及氧自由基吸收能力评价原料、成曲及酱油抗氧化活性,并对酱油活性物质和抗氧化能力进行相关性分析。结果表明,添加麦胚能显著提高酱油总氮、氨基态氮、总酚、总黄酮及美拉德产物的含量（P＜0.05）,从而提升酱油抗氧化活性。麦胚添加量越多,原料、成曲抗氧化能力则越高,但酱油抗氧化能力先增大后减小。大豆、面粉、麦胚的配比为7∶1∶2时（S2）,酱油的抗氧化活性最高且显著高于对照组S1（P＜0.05）。酱油总酚、美拉德产物与酱油抗氧化能力均呈极显著性正相关（P＜0.01,r＞0.8）,推测这些物质是酱油抗氧化活性的主要物质基础;而总黄酮分别与DPPH自由基清除能力、ABTS自由基清除能力、还原力及氧自由基吸收能力之间相关性不高（r＝0.292、0.446、0.703、0.397）,故无法通过总黄酮含量高直接评价酱油抗氧化活性高。因此,在高盐稀态酱油酿造过程中,麦胚可部分替代面粉,从而提高酱油总氮、氨基态氮及抗氧化活性。     

Role of carbohydrases on the release of reducing sugar, total phenolics and on antioxidant properties of oat bran

Aqueous solutions of medium oat bran flour were treated with four carbohydrases viscozyme, celluclast, alpha-amylase, and amyloglucosidase, and then extracted with equal volume of methanol. The resulting extracts were examined for their reducing sugar content, total phenolic content (TPC), oxygen radical scavenging absorbance capacity (ORAC), hydroxyl radical scavenging effect, superoxide scavenging activity, and ferrous ion chelating potential. The amount of reducing sugar increased form 2.0% in the control sample to 21.4% in the sample treated with four fungal beta-glucanase units/g of bran. The increase in reducing sugar was also associated with subsequent increase of other extractable compounds. The total phenolic content as measured by Folin-Ciocalteu’s method ranged from 0.50 to 4.80 mg of gallic acid equivalents/g of bran, whereas the ORAC values were 14.4-25.4 μM of Trolox equivalents/g of bran. All the samples treated with carbohydrases had higher TPC content and higher ORAC values than the control sample (no enzyme treatment). In the hydroxyl radical scavenging assay, except for the alpha-amylase treated sample, all other samples demonstrated a greater inhibition power than the control. These results indicated that pre-treatment of oat bran with cell wall degrading enzymes (i.e. carbohydrases) is a way to increase the amount of extracted phenols as well as the antioxidant properties of oat bran samples.     

麦胚提取物的抗氧化性研究

麦胚是面粉生产的副产物，由于含有多种功能成分，往往被用作功能辅料来提高食品的营养价值。本文利用多种评价体系对麦胚水提物和醇提物的抗氧化性做了研究，并以BHT和抗坏血酸作为参照，结果发现：麦胚提取物显示了很强的DPPH自由基清除能力、羟基自由基清除能力、过氧化氢清除能力、络合能力、还原能力和脂质体自由基的清除能力，并且抗氧化能力随着浓度的增加而增加。实验结果表明，小麦胚芽提取物可以作为某些食品的抗氧化剂使用。     

PHYSICAL,CHEMICAL, and THERMAL CHARACTERIZATION of WHEAT FLOUR MILLING COPRODUCTS1,2

Hard red winter (HRW) and hard red spring (HRS) wheat milling coproducts (bran, germ, shorts, and red dog) from three commercial flour mills and the Kansas State University pilot mill were evaluated for differences in physical, chemical, and thermal properties. the ranges of bulk density for bran, germ, and red dog determined at three moisture levels were 146.5 to 205.2 kgm^?3, 269.2 to 400.6 kgm^?3, and 298.9 to 398.1 kgm^?3, respectively. the true density ranking order was: red dog >shorts = germ >bran, independently of the moisture level. Red dog had the smallest geometrical mean diameter with the highest variation (coefficient of variation of 23.8%). There was a significant (P < 0.05) difference among wheat blends and milling flows in the thickness of bran and germ at the same particle separation size. the image analysis study determined that the equivalent projected area diameter of bran at the same separation size was significantly (P < 0.05) larger than that of germ. the ratio between the equivalent projected area diameter and the particle thickness were within ranges of 15.7 to 37.6 for bran and 15.5 to 32.2 for germ particles. the chemical composition (ash, protein, lipids and fiber) ranges were determined for each coproduct. Ranges of thermal conductivity for bran, germ, shorts, and red dog were 0.049 to 0.074, 0.054 to 0.0907, 0.057 to 0.076, and 0.063 to 0.080 W(mK)^?1, respectively. Specific heat of coproducts, measured with a differential scanning calorimeter, exhibited a wider range [1.08–1.94 kJ(kgK)^?1] than that observed in whole wheat kernels and wheat flour. the variability observed among the samples was due to the different wheat sources and characteristic milling flows for the flour mills.     

小麦入磨水分和硬度对研磨特性的影响

在间歇式实验制粉系统上研究了硬度和水分调节对小麦研磨特性的影响。皮磨系统对入磨水分的变化敏感，随着水分的增加，小粒度麦渣心的提取率基本保持不变，而大粒度麦渣心的提取率显著降低；皮磨系统面粉出率增加，面粉灰分也降低；细麸皮的出率基本保持不变，而粗麸皮的出率显著增加。用硬麦获得的麦渣、麦心的数量显著高于软麦的，特别是大粒度麦渣心的数量，小粒度麦渣心的数量基本一样；硬麦在皮磨系统面粉的出率低于软麦，而总出粉率高于软麦；硬麦的细麸皮和次粉的出率和软麦基本一致，而粗麸皮的出率显著低干软麦。水分调节和硬度对小麦研磨特性的影响相似。     

Antioxidant and <Emphasis Type="Italic">α</Emphasis>-glucosidase inhibitory activities of different solvent extracts of skullcap (<Emphasis Type="Italic">Scutellaria baicalensis</Emphasis>)

In this study, different solvent extracts of skullcap (Scutellaria baicalensis) were assayed for their total phenol content (TPC), antioxidant activity [determined as DPPH radical scavenging activity, superoxide dismutase (SOD)-like activity, oxygen radical absorbance capacity (ORAC) assay, and comet assay], and α-glucosidaseinhibitory activity. The TPC of skullcap ranged from 9.06 mg/g gallic acid equivalents (GAE) for acetone extract (AE) to 91.8 mg/g GAE for methanol extract (ME). AE, which had a low TPC, exhibited the highest DPPH radical scavenging activity and SOD-like activity. TPC positively correlated with the ORAC assay (r=0.96, p<0.001). All skullcap extracts significantly reduced the hydrogen peroxide-induced DNA damage in human leukocytes. ME with a high TPC and ORAC value showed the highest α-glucosidase inhibition. The difference in the biological activities of the extracts may be due to the differences in their chemical structure or polarity. Therefore, the results obtained indicate that might be a potential source of compounds with health-protective effects. ME, in particular, might be a prospective therapeutic agent for diabetes.     

Antioxidant Activity of Ripe and Unripe Pepino Fruit (Solanum muricatum Aiton)

Abstract: Ripe and unripe exotic pepino fruit were evaluated for antioxidant activity, total phenols, and flavonoid content. The antioxidant potency was investigated by employing various established in vitro systems, such as 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), 2–2′‐azinobis(3‐ethylbenthiazoline‐6‐sulphonic acid (ABTS), hydroxyl radical scavenging, reducing power, ferrous ion chelation, ferric reducing antioxidant power (FRAP), and lipid peroxidation. The EC₅₀ values of ripe ethanolic extract on DPPH radical, reducing power, ferrous ion chelation, ABTS radical, FRAP, hydroxyl radical, lipid peroxidation (brain), and lipid peroxidation (liver) were obtained to be 2.20, 2.81, <5.00, 34.06, 8.53, 1.30, 1.75, and 0.51 mg/mL, respectively. However, the EC₅₀ values for unripe fruit extract were noted to be 3.75, 3.40, 11.25, 40.12, 9.75, 0.80, 1.91, and 0.63 mg/mL, respectively. Ripe fruit exhibited the highest values of antioxidant activity in all the scavenging assays except for hydroxyl radical scavenging assay. Ripe pepino had higher total phenol and flavonoid content than unripe fruit. This study suggests that possible mechanism of the biological activities may be due to free radical scavenging and antioxidant characteristics, which may be due to the presence of polyphenols in the fruit extracts. Practical Application: The ripe and unripe pepino fruit have excellent antioxidant properties, so the results obtained in this study clearly indicate that pepino fruit has a significant potential to use as a natural antioxidant agent and possibly as a food supplement.     

Total phenolic compounds,radical scavenging and metal chelation of extracts from Icelandic seaweeds

Screening of potential antioxidant activities of water and 70% acetone extracts from ten species of Icelandic seaweeds was performed using three antioxidant assays. Significant differences were observed both in total phenolic contents (TPC) and antioxidant activities of extracts from the various species evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, oxygen radical absorbance capacity (ORAC) and ferrous ion-chelating ability assays. Acetone extracts from three Fucoid species had the highest TPC and consequently exhibited the strongest radical scavenging activities. High correlation was found between TPC of seaweed extracts and their scavenging capacity against DPPH and peroxyl radicals, indicating an important role of algal polyphenols as chain-breaking antioxidants. However, water extracts generally had higher ferrous ion-chelating activity than 70% acetone extracts and no correlation was found with their TPC, suggesting that other components such as polysaccharides, proteins or peptides in the extracts were more effective chelators of ferrous ions than phenolic compounds.