Antioxidant Properties of Dark Wheat Bread with Exogenous Addition of Buckwheat Flour

In this study, the antioxidative/reducing activity of buckwheat-enhanced dark wheat breads (BEDWBs), based on the substitution of dark wheat flour (DWF) with buckwheat flour (BF) or flour from roasted buckwheat groats (BFR) at levels of 10, 20, 30 and 50% (w/w), was investigated. The antioxidative activity was measured against the 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS•+), the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) and the superoxide anion radical (O2−•) by photochemiluminescence (PCL), reducing power by Fe(III) reduction and directly by cyclic voltammetry (CV) technique. The Fe(II) chelating capacity was also provided. The substitution of dark wheat bread with white and roasted buckwheat flour up to 50% (w/w) resulted in higher scavenging capacity against free radicals. The chelating and reducing power were above threefold higher as compared to a reference dark wheat bread. The improved antioxidant properties of buckwheat-enhanced dark wheat breads were due to the incorporation of buckwheat flour polyphenols. The high correlation noted between the total phenolic content and antioxidant capacity suggested that these assays may be used to characterize the cereal products enriched by buckwheat flours. Overall, buckwheat-enhanced dark wheat bread could be applied as food with more efficient antioxidant properties

UV-B radiation increases anthocyanin levels in cotyledons and inhibits the growth of common buckwheat seedlings

The impact of short-term UV-B treatment on the content of individual flavonoids and photosynthetic pigments in cotyledons and the growth of common buckwheat (Fagopyrum esculentum Moench) seedlings was investigated. Seeds of four common buckwheat cultivars were germinated in darkness over a period of 4 days and acclimatized for 2 days under a 16/8 h light/dark photoperiod at 24/18 °C day/night, and exposure to 100–120 μmol ∙ m−2 ∙ s−1 of photosynthetically active radiation (PAR). Seedlings were divided into three batches, including two batches subjected to different doses of UV-B (5 W ∙ m−2 and 10 W ∙ m−2, one hour per day) for 5 days, and a control group exposed to PAR only. Exposure to UV-B increased anthocyanin levels in the cotyledons of all examined cultivars, it inhibited hypocotyl elongation, but did not affect the content of photosynthetic pigments. Flavone concentrations increased in cv. Red Corolla and Kora, remained constant in cv. Panda and decreased in cv. Hruszowska. Exposure to UV-B decreased rutin levels in cv. Hruszowska, but not in the remaining cultivars. Cultivars Hruszowska, Panda and Kora appeared to be less resistant to UV-B than Red Corolla. Higher resistance to UV-B radiation in Red Corolla can probably be attributed to its higher content of anthocyanins and rutin in comparison with the remaining cultivars

Interlaboratory Coverage Test on Plant Food Bioactive Compounds and their Metabolites by Mass Spectrometry-Based Untargeted Metabolomics.

Bioactive compounds present in plant-based foods, and their metabolites derived from gut microbiota and endogenous metabolism, represent thousands of chemical structures of potential interest for human nutrition and health. State-of-the-art analytical methodologies, including untargeted metabolomics based on high-resolution mass spectrometry, are required for the profiling of these compounds in complex matrices, including plant food materials and biofluids. The aim of this project was to compare the analytical coverage of untargeted metabolomics methods independently developed and employed in various European platforms. In total, 56 chemical standards representing the most common classes of bioactive compounds spread over a wide chemical space were selected and analyzed by the participating platforms (n = 13) using their preferred untargeted method. The results were used to define analytical criteria for a successful analysis of plant food bioactives. Furthermore, they will serve as a basis for an optimized consensus method

Antioxidant properties of buckwheat enhanced wheat breads

Resumen del póster presentado a la XVI Conference EuroFoodChem: "Translating food chemistry into health benefits" celebrada en Gdansk (Polonia) del 6 al 8 de julio de 2011.Common buckwheat (Fagopyrum esculentum Moench) is recognized as a health promoting food which offer many beneficial health effects for consumers. In this study, antioxidant properties of buckwheat enhanced wheat bread formulas, composed of dark or white wheat flour, unhusked common buckwheat flour, salt and yeast, was investigated. The buckwheat flour substituted dark or white wheat flour at amount of 10, 20, 30 and 50% w/w on total flour basis. The breads were baked in electric oven at 230°C for 30 min. The antioxidant properties of buckwheat enhanced wheat breads were characterized by their chelating and reducing power, and antioxidant capacity measured against ABTS•+, DPPH• and against O2 •- radicals by photochemiluminescence (PCL) assay. The studies showed higher antioxidant properties of reference dark wheat bread as compared to reference white wheat bread. The antioxidant capacity formed by water and lipid soluble antioxidants (PCL assay) and reducing power were threefold higher, chelating power was above fivefold higher whilst scavenging capacity against ABTS•+ and DPPH• radicals was increased by 18% and 21%. Therefore, only substituting from 30 to 50% of dark wheat flour in the bread formula with buckwheat flour resulted in higher antioxidant properties of enhanced dark wheat bread, being generally twice better with comparison to dark wheat bread. On the other hand, substituting 10, 20, 30 and 50% of white wheat flour in the bread formula with buckwheat flour resulted in almost linear increase of chelating and reducing power, scavenging activity against ABTS•+ and DPPH• radicals and antioxidant capacity against O2 •-. The antioxidant properties of buckwheat enhanced white wheat breads, considered as above, were almost fivefold higher for bread with 50% buckwheat flour substitution when compared to those noted in commonly consumed white wheat bread. The improved antioxidant properties of buckwheat enhanced wheat breads might be due to the incorporation of phenolic compounds, mainly rutin and quercetin, which had been shown to possess antioxidant activity. Overall, buckwheat enhanced wheat breads could be developed as a food with more effective antioxidant properties.This research was supported by grant No. 1346/B/P01/2010/38 from the Polish Ministry of Science and Higher Education and by Joint Research Project CSIC- Polish Academy of Sciences 2008PL0025.Peer Reviewe

Elicitation with Sodium Silicate and Iron Chelate Affects the Contents of Phenolic Compounds and Minerals in Buckwheat Sprouts

The study concerned the effect of elicitors on the contents of free flavonoids and phenolic acids, as well as their esters and glycosides, and contents of minerals in 7-day sprouts of common buckwheat. An aqueous solution containing a mixture of sodium silicate and Fe-EDTA (SIL-Fe) was compared with the same concentration of sodium silicate alone (SIL) and water (control). Phenolic compounds were analysed using an HPLC–MS/MS apparatus equipped with an ion-trap mass spectrometer, and analyses were conducted by multiple reaction monitoring of selected negative ions. The contents of macro- and microelements in sprouts were determined by the ICP-AES method, after sample mineralization in a mixture of HNO3 and H2O2. The study showed that SIL-Fe influenced the accumulation of individual phenolics in buckwheat sprouts in different ways. Among the major flavonoids in the buckwheat sprouts treated with SIL-Fe, the content of free forms and esters of (‒)-epicatechin and glycosides of quercetin as well as the total content of flavonoids decreased. Elicitation of buckwheat sprouts with SIL and SIL-Fe reduced the contents of calcium, potassium, copper, and zinc; however, the SIL-Fe treatment caused a 5-fold increase in iron content and a 2-fold increase in silicon content. The ratio of total flavonoids to the iron content of SIL-Fe-treated sprouts was 11.5, which was substantially lower than in the control, where it reached 64. The results of this study indicate that it is possible to produce buckwheat sprouts with a high content of flavonoids and fortified with iron, which may increase the availability of this element

Evaluation of vitamins B1 and B2, soluble proteins and phytic acid in buckwheat enhanced wheat bread

Trabajo presentado al EuroFoodChem XVI, celebrado en Gdansk (Polonia) del 6 al 8 de julio de 2011.Peer reviewe

Allelopathic influence of common buckwheat root residues on selected weed speciesen

This study was conducted to determine if common buckwheat (Fagopyrum esculentum Moench) root residues (BRR) in soil are effective in limiting the growth and metabolic responses of barnyard grass (Echinochloa crus-galli (L.) P. Beauv.), wind grass (Apera spica-venti L.), cleavers (Galium aparine L.), and tiny vetch (Vicia hirsuta L.). After removal of above ground parts, BRR of 14-day-old buckwheat plants remained in soil for an additional 7 days when the weeds were seeded. After 30 days of growth, biomass of above ground parts of the weeds as well as free and bound phenolic acids and flavonoids were determined. Antioxidant capacity and peroxidase activity were measured in barnyard grass and cleavers. The biomass of 30-day-old plants of barnyard grass and cleavers grown in bare soil was approximately 5- and 3.5-fold higher, respectively, than in plants grown in the presence of BRR. BRR did not affect the biomass of wind grass and tiny vetch plants, but activate the antioxidant response, increase in peroxidase activity, and the content of phenolic compounds in weed tissues, which indicates an adaptation to the stressful environmental condition

Influence of the buckwheat bread formulation on the viability of E.coli and P. aeruginosa

Resumen del póster presentado a la XVI Conference EuroFoodChem: "Translating food chemistry into health benefits" celebrada en Gdansk (Polonia) del 6 al 8 de julio de 2011.E. coli and P. aeruginosa are two microbial species affecting foods. E. coli is to date, the most well investigated cause of intestinal infectious diseases, and there are many strains with specific virulence factors which cause disease in humans. It is also known that P. aeruginosa can cause spoilage of foods at low temperatures, because it is a psicrophilic microorganism. Therefore, these microorganisms compromise both human health and food quality. Nowadays, there is an increased interest for healthier and safety foods for achieving the well being of the food consumers. Bread is a fundamental daily dietary food. Buckwheat bread has been recently received much more attention because it is rich in many bioactive compounds such phenolic compounds like rutin and its metabolites. The present investigation aimed to evaluate the effect of buckwheat bread formulation on the microbial viability of those microorganisms that may affect both human health (E. coli) and food quality (P. aeruginosa). The study also intended to gain insight on the contribution of rutin to this property if so. To achieve this goal the effect of different food concentrations of pure rutin as well as two buckwheat flours and four buckwheat enhanced wheat bread samples on the microbial viability was tested. Rutin concentration in food samples was determined by RP-HPLC. Rutin was detected in all samples based on buckwheat. Results seem to indicate those breads prepared mixing wheat and buckwheat negatively affect the viability of both E. coli and P. aeruginosa. Pure rutin in food concentrations also showed a similar effect in a dose depending manner. Therefore, it may be suggested that buckwheat enhanced formulation may contribute to bread conservation, also increasing the antimicrobial properties of bread. The choice of some ingredients could offers great potential to modulate the bread composition to much better technological and functional properties.This research was supported by grant No. 1346/B/P01/2010/38 from the Polish Ministry of Science and Higher Education and by Joint Research Project CSIC- Polish Academy of Sciences 2008PL0025.Peer Reviewe