Total phenolic contents and antioxidant activities of various solvent extracts from whole wheat and bran

AbstractTwo wheat varieties grown in Upper and Delta Egypt were compared for their total phenolic content and antioxidant activities. Three solvent systems have been used to prepare the antioxidant extracts from whole wheat and its bran fraction. The three solvent systems included 50% acetone (v/v), 70% methanol (v/v) and 70% ethanol (v/v). Antioxidant activities were tested using DPPH radical scavenging activity and total flavonoid content. The results showed that the extraction solvents and wheat varieties significantly altered the total phenolics and antioxidant activity of whole wheat and bran, and 50% acetone is a recommended solvent for extracting phenolic compounds from the tested wheat and bran. Also data indicated that the bran fraction was rich in total phenolic content and high power for radical scavenging activity than whole wheat. These results showed that wheat bran could be considered as a potential source of antioxidant agent. Therefore, durum wheat variety (Beni-suef-3) showed high level of total phenol contact and antioxidant properties in bran fraction than common wheat variety (Gemiza-9). So, whole meal wheat products maximize health benefits and strongly recommended for use in food processing

Determination of antioxidant capacity in corn germ, wheat germ and wheat bran using solvent and Microwave-Assisted Solvent Extraction

ABSTRACT Solvent extraction methods are widely used for extracting antioxidant in foods and other sources. In this study, Traditional Solvent Extraction (TSE) and Microwave-Assisted Solvent Extraction (MASE) were utilized to determine the content of antioxidants in corn germ, wheat bran and wheat germ. Corn germ, wheat bran and wheat germ all contain different levels of antioxidants; TSE and MASE were utilized to determine the content of antioxidants in these three samples. TSE was performed at 60 ¨¬C employing three solvents, acetone, hexane and methanol. MASE was performed using the solvent methanol at four different temperatures, 60, 80, 100 and 120 ¨¬C. DPPH (2,2-Diphenyl-1-picrylhydrazyl) Assay was used to determine antioxidant capacity. For all samples, the most antioxidant capacity extracted using the TSE was achieved using methanol as the solvent, results ranged from 0.42-4.69 nmol Trolox/g. Using acetone and hexane as solvents for TSE yielded much lower antioxidant capacities. The MASE demonstrated consistent results compared with the TSE using methanol. In regard to wheat bran and corn germ, the capacity for antioxidants and phenolics content improved with each increase in temperature. Wheat germ yielded 3.36-3.88 nmol/g for the DPPH assay and 1248-1575 ¥ìg catechin equivalents /g for phenolics assay establishing wheat germ as containing the most antioxidant contents of the three samples. Corn germ and wheat bran displayed antioxidant capacities on a much smaller scale. The sample of corn germ¡¯s antioxidant capacity had a range of 0.90-1.19 nmol/g and 539-730 ¥ìg catechin equivalents /g, and wheat bran¡¯s antioxidant capacity and phenolics ranged from 0.39-0.72 nmol/g and 318.2-489.5 ¥ìg catechin equivalents /g. Both extraction methods were found reliable for determining the antioxidant contents of grains when methanol was employed

Potencial antioxidante de extractos de residuos agroalimentarios: estabilización de aceite de maíz

The antioxidant potential of 80% methanolic extracts of some agro wastes (pomegranate peel, apple peel, banana peel, citrus peel, corncob, wheat husk, wheat bran, rice bran, and rice hull) was assessed. The yields of the extracts varied over a wide range (8.83 to 29.9 g/100g of dry weight). TPC, TFC, total flavonols (kaempeferol, quercetin, myricetin; HPLC method), DPPH. radical scavenging and inhibition of linoleic acid peroxidation for the extracts varied significantly (P < 0.05) ranging from 0.16-36.40, 0.026-4.89 g/100g of dry matter, 1.06-2622.41 mg/Kg of dry matter, 11.2-52.6, and 64.8-96.4%, respectively. Pomegranate peel extract, offering the highest TPC, TFC, and total flavonols exhibited superior antioxidant activity followed by apple peel, citrus peel, banana peel, corncob, wheat bran, rice bran, wheat husk, and rice hull. Furthermore, the antioxidant effectiveness of the extracts was assessed using corn oil (CO) as the oxidation substrate. CO samples stabilized with extracts at a concentration of 600 ppm (w/w) were subjected to accelerated aging (60 ºC, oven heating, 30 days; 8 h heating cycle per day), and analyzed periodically for the extent of oxidative alterations following the measurement of conjugated dienes (CD), conjugated trienes (CT), p-anisidine and peroxide values. The correlation between the results of different antioxidant assays and oxidation parameters investigated in the present study indicated that fruit peel extracts, exhibiting higher TPC, TFC, flavonol and scavenging power, were also more potent for enhancing the oxidative stability of corn oil.En este studio se determinó el potencial antioxidante de extractos de methanol al 80%, de distintos resíduos de granada, manzana, frutos cítricos, maíz, trigo y arroz. Los rendimientos de los extractos variaron en un amplio rango (8.89 a 29.9 g/100 g de materia seca). La cantidad total de compuestos fenólicos, de flavonoides y de flavonoles, así como la capacidad para secuestrar radicales y la inhibición de la oxidación del ácido linoleico varió significativamente (P < 0.05). El extracto de piel de granada contenía las cantidades más elevadas de compuestos fenólicos, de flavonoides y de flavonoles y exhibió la capacidad antioxidante más elevada, seguido del de piel de manzana, piel de cítricos, piel de plátano, mazorca de maíz, salvado de trigo, salvado de arroz, cáscara de trigo y cáscara de arroz. Igualmente, se estableció la actividad antioxidante de los extractos usando aceite de maíz como sustrato. Muestras de aceite estabilizadas con los distintos extractos (600 mg/kg) fueron sometidas a oxidación acelerada (60 °C en horno durante 30 días con ciclos de calentamiento de 8 h/día) y periódicamente se determinaron los siguientes índices: dienos y trienos conjugados, índice de panisidina e índice de peróxidos. Finalmente, se estudiaron las correlaciones entre los resultados de los distintos ensayos y los niveles de compuestos con acción antioxidante, destacando los extractos de pieles de fruta por su mayor contenido en compuestos fenólicos, flavonoides y flavonoles, e igualmente por su potencia para aumentar la estabilidad oxidativa del aceite de maíz

The evaluation of antioxidant activity of milling fractions of selected cereals grown in the year 2010

Cereals are good source of biologically active compounds that contribute to reducing the risk of coronary heart disease and also inhibit oxidation in human plasma. The aim of this study was to evaluate of antioxidant potential of four milling fractions of selected cereals grown in the year 2010. Methanol was used to extract the antioxidant compounds from cereals. Free radical scavenging activity of samples was measured using DPPH assay and reducing power was determined using FRAP assay. Secondary was evaluated of total phenolic and flavonoid content of cereal extracts. We found that flour fractions (break flour and reduction flour) showed the lower proportion of the total antioxidant potential than bran fractions (fine bran and coarse bran). Extract from barley had the highest values of antioxidant activity and phenolic content

Anthocyanins and Proanthocyanidins in Natural Pigmented Rice and Their Bioactivities

Natural pigmented rice is mainly black, red, and dark purple and contains a variety of flavones, tannins, phenolic, sterols, oryzanols, and essential oils. Anthocyanins and proanthocyanidins belonging to plant flavonoids are thought of as the major functional components found in black, red, and purple rice and contribute to the intense color of many fruits, vegetables, and pigmented cereals such as blueberries, grapes, red cabbages, and purple sweet potatoes. Recent data have indicated the potential for isolating and characterizing the nutrition and non-nutritive components in colored fruits, vegetables, and cereals for their potential chemopreventive and pharmaceutical agents. This chapter provides up-to-date coverage of pigmented rice in terms of the bioactive constituents, isolation, extraction and analytical methods, and related bioactivities. Special focus has been placed on the anti-inflammation, anticancer, and antiaging processes of the major components found in pigmented rice, especially with regard to germ and bran extracts

A Review of Extraction and Analysis of Bioactives in Oat and Barley and Scope for Use of Novel Food Processing Technologies

peer-reviewedOat and barely are cereal crops mainly used as animal feed and for the purposes of malting and brewing, respectively. Some studies have indicated that consumption of oat and barley rich foods may reduce the risk of some chronic diseases such as coronary heart disease, type II diabetes and cancer. Whilst there is no absolute consensus, some of these benefits may be linked to presence of compounds such as phenolics, vitamin E and β-glucan in these cereals. A number of benefits have also been linked to the lipid component (sterols, fatty acids) and the proteins and bioactive peptides in oats and barley. Since the available evidence is pointing toward the possible health benefits of oat and barley components, a number of authors have examined techniques for recovering them from their native sources. In the present review, we summarise and examine the range of conventional techniques that have been used for the purpose of extraction and detection of these bioactives. In addition, the recent advances in use of novel food processing technologies as a substitute to conventional processes for extraction of bioactives from oats and barley, has been discussed.The authors acknowledge financial support from the NutriCerealIreland project funded under the Food Institutional Research Measure (FIRM 11/SF/317) of the Irish Department of Agriculture, Food and Marine

Phenolic compounds and antioxidant activity of oat bran by various extraction methods

Recent studies have suggested that the health promoting capabilities of oats are due to its antioxidants (tocopherols, tocotrienols, and sterols) found within the bran along with phenolic compounds, such as avenanthramides, p-hydroxybenoic acid and vanillic acid. Long-chain fatty acid oxidation is directly responsible for most off-flavors in food. Since oat bran is a good source of antioxidants, a concentrated extract could be used as a natural preservative, for foods rich in unsaturated long-chain fatty acids. Three methods, traditional solvent (TSE), microwave-assisted solvent (MAS), and supercritical fluid treatment (SFT), were used to obtain the extracts. One extraction temperature in TSE, 60°C, and two extraction temperatures in MAS, 60°C and 100°C, were tested. The DPPH (2, 2\u27-diphenyl-1-picrylhydrazyl) method demonstrated that the MAS-100°C was the most efficient extraction in the group, thereby serving as MAS sample against the TSE and supercritical-treated samples. For the treated samples, oat bran was exposed to supercritical CO2 before extraction. Three different temperatures of CO2 were tested, 25°C, 50°C, and 75°C. The treated samples then underwent MAS-100°C to gather extracts for analysis. The experimental results for the DPPH test favored the SFT-75°C treatment at a 40μl concentration. Therefore, SFT-75°C served as the treated sample in the final three experiments. Antioxidant activity was further tested using two other methods: cholesterol oxidation and the DHA model. The total phenolic content was determined using Folin-Ciocalteau Method. The SFT-75°C treatment showed statistically higher results for antioxidant activity in both the cholesterol oxidation and DHA oxidation experiments over the TSE-60°C or MAS-100°C. In terms of total phenolics, the SFT-75°C treatment showed statistically higher results than TSE or MAS-100°C in terms of catechin equivalency, but no statistical difference was seen among the treatments when compared on the basis of total phenolics per gram of original oat bran sample. However, extraction techniques can be evaluated based on extract yield, which this research demonstrated would be SFE-75°C. In conclusion, the SFT-75°C treatment was the optimal extraction based on antioxidant activity, catechin equivalency for total phenolics, and sample yield. This information could be used in the future development of food products as a natural antioxidant source

PHYTOCHEMICAL PROFILES AND ANTIOXIDANT PROPERTIES OF WHEAT

The present study examined and compared wheat grain, bran, aleurone, and micronized aleurone for their antioxidant properties and phytochemical profiles. The results showed that wheat antioxidants were concentrated in bran fraction, particularly in the aleurone layer of wheat bran. Micronized aleurone demonstrated the highest antioxidant activities (scavenging activities against ABTS+, DPPH, ORAC, and chelating activity), and the highest total phenolics and phenolic acids concentration, suggesting that post-harvest treatment may affect the availability of wheat antioxidants. The present +study also investigated bran samples of seven wheat varieties from four different countries for their antioxidant properties and phytochemical profiles. The bran samples exerted enormous differences in concentrations among their phenolic acids, tocopherols and carotenoids. Their antioxidant activities were also notably different from 13% (scavenging capacity against O2-) to 99% (ORAC). These data suggest that wheat varieties and growing conditions might alter wheat antioxidant properties and phytochemical compositions. In addition, eight selected Maryland grown soft wheat varieties or experimental lines were examined for potential beneficial components and antioxidant properties. These soft wheat varieties significantly differed in their ABTS+ scavenging activity and chelating activity. Significant amount of phenolic acids have been demonstrated in all soft wheat grain. But their phenolic acid content markedly differed among different varieties which mainly (89% - 94%) existed as the insoluble bound form with ferulic acid as the predominant phenolic acid. These data suggest the possibility to produce soft wheat varieties rich in selected health beneficial factors for optimum human nutrition through breeding programs. Finally, five phenolic acids commonly present in wheat grain and fractions were examined and compared for their radical scavenging properties and chelating capacities using spectrophotometric and electron spin resonance measurements. These phenolic acids differed in their properties to react with and quench HO, O2-, ABTS+, and DPPH, as well as their capacities to form chelating complexes with transition metals. Strong structure-activity relationships were observed in the present study. Both substitutes on the phenyl ring and the conjugated carbon skeleton may influence the antioxidant properties of these phenolic acids