Bran Fractions Research Articles

Antioxidant activity and polyphenol content in milling fractions of purple wheat

The aim of this study was to evaluate the antioxidant activity of four milling fractions of purple wheat breeding lines grown in 2010. Radical scavenging activity by the DPPH assay and reducing power of the samples were determined, as well as the content of polyphenols, flavonoids and anthocyanins. The obtained results showed that flour fractions (break and reduction flour) had lower total antioxidant potential than bran fractions (fine and coarse bran). A significant correlation was obtained between the DPPH and reducing power assay (R2 = 0.87). The correlation between antioxidant assays and polyphenol, flavonoid and anthocyanin content suggested that polyphenols in cereals are responsible for the antioxidant activities.

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

Two 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.

The production of Pleurotus sajor-caju in peach palm leaves (Bactris gasipaes) and evaluation of its use to enrich wheat flour

The aim of this study was to evaluate of Pleurotus sajor-caju production in peach palm leaves and the addition of different fractions of mushroom powder to wheat flour to increase its nutritional value without changing its characteristics. The best yield (48.4%), biologic efficiency (4.5%), and Pr (0.36 g/day) values were obtained using 20% inoculum fraction and 10% rice bran fraction. The Pleurotus sajor-caju fruiting body cultivated under these conditions had the following composition in 100 g: 29.91 g (carbohydrates), 42.92 g (proteins), 1.24 g (lipids), 15.93 g (fibers), 7.42 g (ashes), 1.6 g (phosphorus), 2.7 g (potassium), 8.73 mg (iron), 23.75 mg (sodium), 0.34 mg (thiamine), and 0.57 mg (riboflavin). The wheat flour with mushroom powder had reduced sugar content, but it did not have increased fat content. The fiber, protein, phosphorus, potassium, iron, and riboflavin contents were increased mainly when 10% mushroom powder was added to the wheat flour. Furthermore, this flour does not undergo drastic alterations in its physicochemical characteristics such as in moisture, wet gluten, color, and falling number.

Antioxidant bioaccessibility from wheat aleurone throughout the canine gastrointestinal tract: an in vitro study (1044.14)

Enhancing overall health status through nutrition has growing interest in humans and animals and thus, the market for food and feed formulations with added functional dietary ingredients is on the rise. Health‐promoting properties of wheat are documented in vivo and in vitro, and are partially attributed to antioxidant compounds in the bran fraction. Cargill isolates the aleurone fraction from wheat bran which is used as an ingredient in companion animal diets with the expectation of promoting a healthier diet. However, for bioactive compounds to be efficacious, they must be bioaccessible (available for absorption) during the digestive process. Our studies indicated antioxidants from aleurone are more bioaccessible than those from beet pulp fiber (BP) in an in vitro dynamic digestive system (TNO) validated for the GI‐tract of dogs. Results show low molecular weight antioxidant compounds become bioaccessible in the jejunum compartment of the small intestine but not in the ileum (TIMdog‐1), and antioxidant activity is comparable among the substrates. Furthermore, additional antioxidant compounds are released during fermentation (lower GI, TIMdog‐2) of the non‐digested fraction, with cumulative antioxidant activity being about 25% higher from aleurone than BP. Thus, supplementing pet food with wheat aleurone fractions may be a strategy for improved health benefits in a canine diet.

Processing of commercial rice bran for the production of fat and nutraceutical rich rice brokens, rice germ and pure bran

Successive sieving of commercial rice bran on the basis of particle size was performed and different fractions were obtained of which the rice brokens and rice germ fractions contained fat 33 g/kg and 207 g/kg, oryzanol 400 mg/kg and 874 mg/kg, total tocols (tocopherols and tocotrienols) 16.5 mg/kg and 87.8 mg/kg, and total phytosterols 128.7 mg/kg and 769.6 mg/kg respectively, thus indicating that these fractions are a good source of fat and nutraceuticals. The residual fat (6 g/kg) from commercial defatted rice bran contained high oryzanol content of 4.8 g/100 g, indicating that commercial defatted rice bran as a source of oryzanol. The fat from pure rice bran fraction of commercial rice bran decreased in the color value (48.5%) indicating that sieving could also improve the quality of crude rice bran oils.

Milling of Canadian oats and barley for functional food ingredients: Oat bran and barley fibre-rich fractions

Izydorczyk, M. S., McMillan, T., Bazin, S., Kletke, J., Dushnicky, L., Dexter, J., Chepurna, A. and Rossnagel, B. 2014. Milling of Canadian oats and barley for functional food ingredients: Oat bran and barley fibre-rich fractions. Can. J. Plant Sci. 94: 573–586. Oats and barley are recognized for their valuable fibre constituents having protective and therapeutic effects against the development of diet-related disorders. Mixed linkage (1–3), (1–4)-β-D-glucans, the major dietary fibre constituents in oats and barley, have been linked to blood cholesterol lowering properties of these grains. The objective of this study was to compare oat bran and barley fibre-rich fractions (FRF) as two products with elevated levels of β-glucans and obtained by similar roller milling processes. The content of β-glucan in oat brans prepared from three different cultivars (AC Morgan, HiFi, and CDC ProFi) ranged from 7.90 to 9.50%, whereas the content of β-glucans in FRF prepared from three barley cultivars (CDC McGwire, CDC Fibar, and CDC Hilose) ranged from 9.31 to 18.19% (dwb). The yields of oat brans ranged from 44 to 49% and the yields of barley FRF from 39–49%. Both preparations contained higher amounts of arabinoxylans, proteins, and ash compared with the original grains. The oat brans were made up mainly of fragments containing the outer grain layers with a substantial portion of the subaleurone starchy endosperm attached to them, whereas the barley FRF consisted primarily of fragments containing the endosperm cell walls, with a smaller proportion of the outer grain tissues. The barley FRF contained smaller particles with broader distribution of particle size than the oat brans. The oat bran particles had higher bulk density and lower porosity than the barley FRF. Both preparations showed pronounced viscosity-building properties when dispersed in water at 45°C, but exhibited different viscosity profiles and differences in the attainable viscosity values.

From wheat to sourdough bread: a laboratory scale study on the fate of deoxynivalenol content

The effect of wheat processing by scouring, milling and sourdough bread making on the fate of deoxynivalenol was studied using wheat samples artificially contaminated with Fusarium graminearum. The scourer assures an intensive treatment of grain surface, allowing the reduction of deoxynivalenol content by 34.6-46.2%. After milling, the deoxynivalenol was found in all wheat mill fractions. The highest deoxynivalenol contents were found in bran fractions (bran and shorts). Concerning the flour fractions, those with low ash content, resulting from the first break and first reduction flours, were found to have higher deoxynivalenol concentrations than other flour fractions. The sourdough fermentation with selected lactic acid bacteria allowed the significant decrease (58.6-66.5%) of deoxynivalenol content of flour, while the spontaneous fermentation induced a much lower decrease (26.2-29.1%). The baking process caused the reduction of deoxynivalenol content by 11.4-15.5% compared to fermented dough.

Investigation of the interaction between soluble antioxidants in green tea and insoluble dietary fiber bound antioxidants

This work investigates the possibility of interaction between insoluble dietary fiber bound antioxidants, specifically of wheat bran, and soluble antioxidants like those provide by aqueous infusions of green tea. Solutions of pure catechins were also assayed for comparison with those naturally found in tea. To accomplish this, the aqueous and alcohol soluble fractions as well as the lipid components of wheat bran were firstly removed and the freeze-dried insoluble residue was then treated with different concentrations of green tea infusions or aqueous solutions of epicatechin (EC) and epigallocatechin-3-gallate (EGCG) for certain time. Treatment with EC (0–200μM) had no significant effect on the antioxidant capacity of insoluble bran fraction. However, treatment with EGCG significantly (p<0.05) increased linearly the antioxidant capacity as a function of concentration (0–100μM). Treatment with great tea infusions (1–3g/100ml) also increased the resulting antioxidant capacity of insoluble bran fraction, but the effect was lesser at higher infusion concentrations. Liquid chromatography couple to mass spectrometry (LC–MS) analyses of aqueous phases after treatment indicated comparable levels of decrease in the concentrations of catechins confirming their reaction with the radical forms of antioxidants bound to insoluble bran matrix.

Improving bioaccessibility and bioavailability of phenolic compounds in cereal grains through processing technologies: A concise review

Bioactive phenolic compounds in cereal grains are mainly located in the bran fraction and covalently bound to indigestible polysaccharides. They have very low bioavailability because the complex bran matrix severely hinders their access to the necessary enzymes which contribute to their release in the human gastrointestinal tract. Liberating these phenolic compounds from bran matrices and/or increasing their accessibility have been demonstrated to be effective in enhancing their bioavailability. For this purpose, various processing technologies have been developed. The aim of this study was to concisely review these processing technologies including mechanical treatment, thermal treatment, extrusion cooking, and bioprocessing.

Distribution and Speciation of Iron and Zinc in Grain of Two Wheat Genotypes

This study aimed to determine differences among wheat cultivars in the distribution and speciation of Fe and Zn in grain milling fractions. Cultivars with higher Fe and Zn concentrations in the wholemeal flour were found to contain higher concentrations in the white flour. Soluble Fe and Zn were extracted and analyzed by size exclusion-inductively coupled plasma mass spectrometry. Fe speciation varied between milling fractions with a low molecular weight (LMW) complex likely to be Fe-deoxymugenic acid/nicotianamine being the predominant extractable Fe species in white flour, accounting for approximately 85% of the extractable Fe. Bran fractions had a lower amount of LMW-Fe form but more as soluble Fe-phytate and an unidentified high molecular weight peak. In the white flour fraction soluble Zn was found to be present mainly as a LMW peak likely to be Zn-nicotianamine complex. Soluble Fe-phytate was found in the white flour fraction of a high-Fe cultivar but not in a low-Fe cultivar.

Bioavailability and metabolism of hydroxycinnamates in rats fed with durum wheat aleurone fractions.

The consumption of wholemeal cereals has been associated with the reduced risk of several chronic diseases, and the mechanisms behind these protective effects may be linked, besides dietary fiber and micronutrients, to an increased intake of hydroxycinnamates contained in the bran. Among bran fractions, aleurone usually contains the highest concentration of ferulic acid and diferulic acid esters linked to arabinoxylans representing the most relevant subclasses. The aim of the present study was to evaluate the absorption of hydroxycinnamates by measuring the urinary metabolite profiles of rats fed with the two different aleurone fractions (the inner part of the aleurone, named wheat aleurone A, WA-A, and the outer part, named wheat aleurone B, WA-B). An acute feeding experiment with two rat groups consuming equivalent amounts of total ferulic acid from the different aleurone fractions was carried out to evaluate ferulic acid bioavailability as affected by different sources. A chronic feeding experiment was also conducted with two rat groups consuming the same amount of the two different aleurone fractions, carried out to investigate the short-term metabolism and absorption of aleurone phenolics. The results revealed higher increases in the 24 h-excretion of phenolic metabolites/catabolites in aleurone fed rats compared to rats fed with a regular diet. Specifically, in the chronic feeding, ferulic acid was more bioavailable when WA-A was ingested. Based on previous observations, demonstrating various positive physiological responses to ferulic acid and aleurone fractions characterized by higher phenolic bioavailability, our results indicate that the WA-A fraction has potentially interesting nutritional characteristics that might be used for the formulation of new wheat based products.

Effect of sourdough processing and baking on the content of enniatins and beauvericin in wheat and rye bread

The occurrence of the emerging mycotoxins enniatins (ENNs) and beauvericin (BEA) has been reported in Fusarium-infected cereals. To study the effect of sourdough processing and baking on ENN B, ENN B1, and BEA concentrations, a recently developed stable isotope dilution assay for these mycotoxins was used. After milling of wheat and rye grains naturally contaminated with ENN B and ENN B1, approximately 70–82 % of the two ENNs were found in the bran fraction and the rest remained in flour. BEA was added to flour before sourdough fermentation. In an experiment on a microscale, dough was fermented for 24 h at 30 or 40 °C, which reduced part of the ENNs and BEA in particular at 40 °C. On a standard scale, mixing, resting, and proofing of the bread dough resulted in 13–19 % reduction of the ENNs compared with flour, but in no significant change of BEA. The final baking at 200 °C for 25 min led to a further decrease of the ENNs and BEA, ranging from 9 to 28 % compared with fermented dough. In case of rye sourdough bread, greater reductions of ENNs were found in crust than in crumb. For both wheat and rye flours, overall 25–41 % of ENN B, ENN B1, and BEA were reduced during the whole sourdough bread-making process.

Wheat bran particle size influence on phytochemical extractability and antioxidant properties

It is unknown if particle size plays a role in extracting health promoting compounds in wheat bran because the extraction of antioxidant and phenolic compounds with particle size reduction has not been well documented. In this study, unmilled whole bran (coarse treatment) was compared to whole bran milled to medium and fine treatments from the same wheat bran. Antioxidant properties (capacity, ability, power), carotenoids and phenolic compounds (phenolic acids, flavonoids, anthocyanins) were measured and compared. The ability of whole bran fractions of differing particle size distributions to inhibit free radicals was assessed using four in vitro models, namely, diphenylpicrylhydrazyl radical-scavenging activity, ferric reducing/antioxidant power (FRAP) assay, oxygen radical absorbance capacity (ORAC), and total antioxidant capacity. Significant differences in phytochemical concentrations and antioxidant properties were observed between whole bran fractions of reduced particle size distribution for some assays. The coarse treatment exhibited significantly higher antioxidant properties compared to the fine treatment; except for the ORAC value, in which coarse was significantly lower. For soluble and bound extractions, the coarse treatment was comparatively higher in total antioxidant capacity (426.72mg ascorbic acid eq./g) and FRAP value (53.04μmol FeSO4/g) than bran milled to the finer treatment (314.55 ascorbic acid eq./g and 40.84μmol FeSO4/g, respectively). Likewise, the fine treatment was higher in phenolic acid (7.36mg FAE/g), flavonoid (206.74μg catechin/g), anthocyanin (63.0μg/g), and carotenoid contents (beta carotene, 14.25μg/100g; zeaxanthin, 35.21μg/100g; lutein 174.59μg/100g) as compared to the coarse treatment. An increase of surface area to mass increased the ORAC value by over 80%. With reduction in particle size, there was a significant increase in extracted anthocyanins, carotenoids and ORAC value. Particle size does effect the extraction of phytochemicals.

Effect of bioprocessing and particle size on the nutritional properties of wheat bran fractions

Abstract In this work, the influence of bioprocessing on the nutritional quality and health effects of wheat bran of different particle sizes (750, 400, 160, 50 μm) was evaluated. Bioprocessing was carried out by a 24 h-fermentation using Lactobacillus brevis E95612 and Kazachstania exigua C81116 as starters, with or without the addition of an enzyme mixture with specific carbohydrase activities. Bioprocessing clearly affected the microstructure and chemical and nutritional features of wheat bran depending on the particle size. Bioprocessing significantly improved the antioxidant and phytase activities (up to 3.7 fold, respectively), peptides and total free amino acids and content (up to 40%) and the in vitro digestibility of proteins. The antioxidant power and nutritional indexes were higher for the bioprocessed brans compared to the native, mainly in bran having smaller particle size. In every case, the addition of the enzymes further improved the positive effect of the microbial fermentation. Industrial relevance Wheat bran is a source of nutritionally important compounds such as dietary fibers, minerals, vitamins and phenolic acids. Commonly, processing of bran has mostly been performed for technological purposes, to facilitate its use as a DF rich ingredient in foods improving its structural and organoleptic features. The bioprocessing technology here applied offers a tool to enhance also the nutritional value of wheat bran, especially of finer particle size. As a result, bioprocessed wheat bran showed higher potential compared to the native bran, and qualified as a suitable ingredient for food preparations.

Arabinoxylan and Arabinogalactan Content in Different Spring Wheats

In the present study, an effort has been made to characterize eight different spring wheats for arabinoxylan and arabinogalactan content. For the purpose, non-starch polysaccharides were extracted, derivitized with hexamethyldisalazine, and further analyzed through a gas chromatograms flame ionization detector. Arabinose, xylose, and galactose content ranged from 21.66 to 40.02 g/100 g, 23.95 to 48.09 g/100 g, and 37.44 to 50.02 g/100 g, respectively. The arabinoxylan and arabinogalactan content in whole wheat flour ranged from 2.93 to 4.68 g/100 g and 0.47 to 0.93 g/100 g, respectively, while in bran it contained 11.71 to 18.38 g/100 g and 1.07 to 4.43 g/100 g, respectively. Conclusively, significant variations regarding arabinoxylan and arabinogalactan content were estimated among all spring wheat varieties and their bran fraction.

Whole Grains from a Mechanistic View

Wheat, rice, and corn are the most widely eaten whole grains, followed by oats, rye, and barley. A wheat kernel consists of 80–85% endosperm, 10–14% bran, and 2.5–3% germ (Figure 1). Whole grains contain a high amount of bioactive substances such as fiber, vitamins, minerals, antioxidants, and other phytochemicals such as betaine, choline, sulfur amino acids, and melatonin, which account for at least 15% of the whole grain by weight. Most bioactive substances are in the bran (about 52% by weight) and the germ (at least 24% by weight) fractions. In refined cereals, the levels of bioactive compounds are substantially reduced due to the complete or partial removal of the germ and bran fractions.

Phytochemical composition of extracts from wheat grain fractions obtained by tangential abrasive dehulling

This study examined the phytochemical content and composition of extracts from wheat bran fractions obtained by abrasive dehulling.Wheat grain was fractionated using a Tangential Abrasive Dehulling Device (TADD). The aqueous ethanol extracts of whole wheat, bran, TADD and commercial aleurone samples were analyzed for their total phenolic content (TPC), oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity (DPPH). The fractions with the highest antioxidant capacity were further analyzed for their tocopherol, phenolic acid, carotenoid and organic acid contents. The correlations between chemical composition and antioxidant properties of wheat extracts were developed.All TADD samples had higher tocopherol contents than the bran from a quadrumat senior mill. Lutein was the primary carotenoid in all the samples. Ferulic and caffeic acids were the strongest contributor to DPPH and TPC of the extracts, respectively. Correlation between ORAC and tocols content of the samples was positive and strong (r = 0.75793, p < 0.0001). This study demonstrated that TADD was more effective than quadrumat senior mill to obtain wheat bran fractions enriched in health beneficial phytochemicals. The correlations between chemical composition and antioxidant properties of TADD bran extracts developed in this study are helpful to formulate products with desired efficacy.

Dissociation of aleurone cell cluster from wheat bran by centrifugal impact milling

Wheat aleurone which contains most of the nutritionally important substances of wheat bran has been widely investigated, and electrostatic separation based on the distinct electrical properties of bran tissues has been proven to be effective for the enrichment of aleurone layer. In order to obtain a suitable starting material containing single-layer bran strips for the electrostatic separation, centrifugal impact milling was utilized to dissociate wheat bran constitutive tissues. During centrifugal impact milling, the outer pericarp was detached when the particle size of the fragments decreased to approximate 460μm, whereas the aleurone layer consisted of 20–30 intact cells in single-layer was completely dissociated until the particle size decreased to about 200μm. Moreover, the detached behaviors of bran tissues were well explained by the relationship of their elastoplasticities, the rupture-energy and peeling force generated by the rotating blade tip. After centrifugal impact milling and sieving, the bran fraction with the median particle diameter of 144μm contained 61% single-layer aleurone cell clusters, indicating that it could be a superior starting material for the electrostatic separation of wheat aleurone.

Effect of defatting and decortication on distribution of fatty acids, phenolic and antioxidant compounds in sorghum (Sorghum bicolor) bran fractions

SummarySorghum bran components could be a potential source of nutrients and phytochemicals for industrial applications. The effect of defatting with hexane and different degrees of decortication on distribution of fatty acids, phenolic compounds, colour (L, a and b) and antioxidant activity (DPPH) of red (RS) and white (WS) sorghums was studied. The decortication process was carried out at time intervals of 1–6 min. Defatted and nondefatted fractions were analysed. The content of polyunsaturated fatty acids (PUFA) was higher than monounsaturated fatty acids (MUFA); the content of MUFA was higher than saturated fatty acids (SFA). Linoleic, oleic and palmitic acids predominated in all fractions. Significant differences in the content of palmitic and linolenic acids between sorghums were found. RS had higher content of palmitic, and WS was higher in linoleic acid. Defatted samples contained lower amounts of phenolic compounds and higher antioxidant activities, than nondefatted samples. RS was a better source of total phenolic compounds and antioxidant activity compared with WS, but WS presented a more suitable profile of fatty acids. In conclusion, fractions of both types of sorghums can be used in cereal‐based products to enhance their phytochemical profile.

How the sourdough may affect the functional features of leavened baked goods

Sourdough fermentation is one of the oldest food biotechnologies, which has been studied and recently rediscovered for its effect on the sensory, structural, nutritional and shelf life properties of leavened baked goods. Acidification, proteolysis and activation of a number of enzymes as well as the synthesis of microbial metabolites cause several changes during sourdough fermentation, which affect the dough and baked good matrix, and influence the nutritional/functional quality. Currently, the literature is particularly rich of results, which show how the sourdough fermentation may affect the functional features of leavened baked goods. In the form of pre-treating raw materials, fermentation through sourdough may stabilize or to increase the functional value of bran fractions and wheat germ. Sourdough fermentation may decrease the glycaemic response of baked goods, improve the properties and bioavailability of dietary fibre complex and phytochemicals, and may increase the uptake of minerals. Microbial metabolism during sourdough fermentation may also produce new nutritionally active compounds, such as peptides and amino acid derivatives (e.g., γ-amino butyric acid) with various functionalities, and potentially prebiotic exo-polysaccharides. The wheat flour digested via fungal proteases and selected sourdough lactobacilli has been demonstrated to be probably safe for celiac patients.