Sara Rodrigo

Agronomic selenium biofortification in Triticum durum under Mediterranean conditions: From grain to cooked pasta

To improve the nutritional value of durum wheat and derived products, two foliar Se fertilisers (sodium selenate and selenite) were tested at four rates (0-10-20-40gha(-1)) in 2010/2011 and 2011/2012 in southwestern Spain. There was a strong and linear relationship between total Se or selenomethionine (Se-Met) accumulation in grain and Se dose for both fertilisers, although selenate was much more efficient. Se-Met was the main Se species (≈90%) of the total Se extracted from all materials. Milling caused a 27% loss of Se due to the removal of Se located in bran and germ. In the pasta making process and the cooking process the loss of Se, mainly as selenite, was about 7%. Durum wheat may be a good candidate to be included in Se biofortification programs under rainfed Mediterranean conditions, as foodstuffs derived from it could efficiently increase the Se content in the human diet.

Selenium Speciation in Malt, Wort, and Beer Made from Selenium-Biofortified Two-Rowed Barley Grain

Selenium (Se) biofortification of barley is a suitable strategy to increase the Se concentration in grain. In the present paper, the suitability of this Se-biofortified grain for making Se-enriched beer is analyzed. The aim of the present study was to evaluate the effect of different Se fertilizer doses (0, 10, and 20 g of Se ha(-1)) and forms (sodium selenate or sodium selenite) on the Se loss during the malting and brewing processes and Se speciation in grain, malt, wort, and beer. Samples were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) and high-performance liquid chromatography (HPLC)-ICP-MS for total Se and speciation. Mashing-lautering was the process with the greatest Se loss (83.8%). After malting and brewing, only 7.3% of the initial Se was retained in beer, mainly in selenite form. Even so, the fertilizer application of sodium selenate at 20 g ha(-1) increased the total Se concentration almost 6-fold in the final beer in comparison to the use of grain derived from unfertilized barley. The present paper provides evidence that the use of Se-biofortified barley grain as a raw material to produce Se-enriched beer is possible, and the results are comparable to other methods in terms of efficiency.

Selenium biofortification in bread-making wheat under Mediterranean conditions: influence on grain yield and quality parameters

Abstract. The diet of millions of people around the world is deficient in selenium (Se). Bread-making wheat has been successfully used in Se biofortification programs under temperate climate to remedy Se deficiency. However, its suitability under Mediterranean conditions and its effect on the grain yield and quality parameters are not well known. In a wheat field in south-western Spain, two foliar Se fertilisers (sodium selenate and sodium selenite) were applied at four application rates (0, 10, 20, 40 g ha–1) in 2010–11 and 2011–12. Results showed a strong and linear relationship between total Se in grain and Se dose for both fertilisers, although selenate was much more efficient. A dose of 10 g sodium selenate ha–1 was able to increase significantly the Se in grain to close to the recommended values, although Se loss of 28% during the milling process might be expected. Grain yield was not negatively affected by fertilisation, but grain protein and dry gluten were slightly negatively affected, but only in the dry year. Alveograph parameters were either not affected or slightly favoured by Se fertilisation in any studied year. Bread-making wheat is a good candidate to be included in biofortification programs under semi-arid Mediterranean conditions.

Selenium in commercial beer and losses in the brewing process from wheat to beer

There is increasing interest in enhancing the micronutrient composition of cereals through fertilization. The aims of this study were (1) to determine the Se concentration of commercial beers retailing in the UK, and (2) to test if the transfer of Se, from biofortified grain to final beer product, is <10% under UK cultivation conditions, as seen previously under Mediterranean conditions. The Se concentration of 128 commercial beers was measured, using inductively coupled plasma-mass spectrometry (ICP-MS). The selenium content of commercial beers varied 6.5-fold, with beers originating from America having higher Se concentrations than those from Europe. Laboratory-scale brewing trials with isotopically-enriched (77)Se wheat, sampled from UK field-sites, showed that most (77)Se losses in the brewing process occurred during mashing (54%), with fermented beer containing ∼ 10% of the (77)Se initially present in the wheat grain. Total N values in wort and malt were positively correlated with the (77)Se content of the wheat grain.

Hyfraxins A and B, cytotoxic ergostane-type steroid and lanostane triterpenoid glycosides from the invasive ash dieback ascomycete Hymenoscyphus fraxineus

HIGHLIGHTSA new steroidal glycoside and a related glycosylated triterpenoid were identified.Producer is the ash dieback pathogen Hymenoscyphus fraxineus.Their stereochemistry was assigned including absolute configuration.Both compounds exhibited cytotoxic activity against the murine cell line L929. ABSTRACT A virulent culture of Hymenoscyphus fraxineus, the causal agent of ash dieback, was investigated for its production of secondary metabolites in a 70 L batch fermentation. Chemical analysis of the mycelial extract by means of flash chromatography and preparative HPLC led to the isolation of a new ergostane‐type steroid (1) and a new related lanostane triterpenoid (2), both revealing the same glycosylation pattern. While their planar structures were elucidated by HR‐ESIMS and NMR data, relative stereochemistry was assigned by ROESY correlations in conjunction with H,H and C,H coupling constants. Absolute configuration was determined based on ROESY correlations between the aglycons and the sugar moieties, which were identified in both cases as d‐mannose by GC/MS analysis of the trimethylsilylated derivatives. The isolated compounds, for which we propose the trivial names hyfraxins A (1) and B (2), were found to be cytotoxic against the mouse fibroblast cell line L929 and exhibited moderate to weak activity against Gram‐positive bacteria.

Antagonism between Byssochlamys spectabilis (anamorph Paecilomyces variotii) and plant pathogens: Involvement of the bioactive compounds produced by the endophyte

Fungal endophytes can be part of the defensive system of plants against multiple pathogens by competing for resources, hyperparasitism or producing bioactive compounds with antimicrobial properties. There is an ever-increasing interest for obtaining new and environmentally friendly products to use in the fight against pathogens. With this purpose, Byssochlamys spectabilis (anamorph Paecilomyces variotii), which is a fungal species that commonly occurs, was evaluated as an antagonistic organism towards three phytopathogens (Biscogniauxia mediterranea, Fusarium moniliforme and Phytophthora cinnamomi). First, an in vitro experiment was designed to test the effect that the endophyte filtrate had on the three pathogens. The endophyte filtrate decreased the radius growth rate of F. moniliforme by nearly 10%. Consequently, the antagonism between B. spectabilis and F. moniliforme was evaluated in Lolium rigidum plants under greenhouse conditions by means of co-inoculations. The endophyte produced a decrease of 50–75% in the disease severity caused by the pathogen in the earliest infection stages. Crude extracts of B. spectabilis were obtained to determine the secondary metabolites responsible for such an effect. The bioactivity-guided chromatography and HPLC-MS (high performance liquid chromatography coupled with mass spectrometry) of the active fraction suggested that the antibiotic activity was caused by viriditoxin. In conclusion, the fungal endophyte B. spectabilis and/or its bioactive compounds showed antagonism towards several phytopathogens and deserves further study to investigate its actual potential for use as a biocontrol agent.