Use of near-isogenic wheat lines to determine the glutenin composition and functionality requirements for flour tortillas

In wheat ( Triticum aestivum L), the synthesis of high molecular weight (HMW) glutenins (GS) is controlled by three heterologous genetic loci present on the long arms of group 1 wheat chromosomes. The loci Glu-A1, Glu-B1, and Glu-D1 and their allelic variants play important roles in the functional properties of wheat flour. This study focused on understanding the functionality of these protein subunits on tortilla quality. Near-isogenic wheat lines in which one or more of these loci were absent or deleted were used. Tortillas were prepared from each deletion line and the parent lines. The elimination of certain HMW-GS alleles alter distinct but critical aspects of tortilla quality such as diameter, shelf stability, and overall quality. Two deletion lines possessing HMW-GS 17 + 18 at Glu-B1 and deletions in Glu-A1 and Glu-D1 had significantly larger tortilla diameters, yet tortilla shelf life was compromised or unchanged from the parent lines used to develop the deletion lines or the commercial tortilla flour used as a control. Alternatively, a deletion line possessing Glu-A1 and Glu-D1 (HMW-GS 1, 5 + 10) and a deletion in Glu-B1 also significantly improved tortilla diameters. Whereas the increase in diameter was less than the line possessing only HMW-GS 17 + 18 at Glu-B1, the stability of the tortillas were, however, maintained and improved as compared to the parent lines containing a full compliment of HMW-GS. Thus, the presence of subunits 5 + 10 at Glu-D1 alone or in combination with subunit 1 at Glu-A1 appears to provide a compromise of improvement in dough extensibility for improved tortilla diameters while also providing sufficient gluten strength to maintain ideal shelf stability.     

Proanthocyanidins: target compounds as antibacterial agents

Grape seeds accumulate in huge quantities as byproduct during wine production and are therefore a cheap source for pharmacologically active agents. However, studies prove poor antibacterial activity, and results of analyses are sometimes contradictory. The aim of this study was, thus, to determine the antibacterial activity of grape seed extracts with special focus on the chromatographic characterization of active fractions. In the course of these investigations, extraction protocols were optimized so that microwave-assisted extraction (MAE) guaranteed highest preconcentration efficiency. Proanthocyanidins, monomeric flavonoid aglycones, as well as some of their glycosides could be identified within yielded extracts via high-performance liquid chromatography-mass spectrometry (HPLC-MS). By that means the coherence number of possible isomers of procyanidins was approximated by a newly developed equation. As far as antibacterial activity determined via screening tests is concerned, the extracts generally have been found to be positively responsive toward 10 different gram-positive and gram-negative bacteria strains. After fractionation of the raw extracts, proanthocyanidins P2, P3, P4 and gallate esters P2G and P3G (P = proanthocyanidin consisting of catechin and epicatechin units, n = oligomerization degree, G = gallate ester) were determined as active antibacterial agents toward 10 different pathogens. Only moderate activity was found for monomeric flavonoid fractions.     

Inadequate intakes of dietary zinc among pregnant women from subsistence households in Sidama, Southern Ethiopia

OBJECTIVE: To assess the prevalence of zinc inadequacy based on dietary intakes and plasma zinc concentrations and, simultaneously, the prevalence of inadequate intakes of energy, protein, calcium and iron. DESIGN: A cross-sectional study of a convenience sample of subsistence farming households in Sidama, Southern Ethiopia. SUBJECTS: Dietary intakes were calculated from 1-day weighed food records and 40 repeats from 99 pregnant women in the third trimester using analysed values of major staple foods for zinc, iron, calcium and phytate. The distribution of observed intakes was adjusted for usual intakes and the prevalence of inadequacy estimated using the estimated average requirement (EAR) cutpoint method. Prevalence of inadequacy for zinc, protein and iron intakes were compared with those based on biochemical measures. RESULTS: Prevalence of zinc inadequacy was very high: 99% for US FNB EAR and 100% for IZiNCG EAR compared to 72% based on low plasma zinc concentrations. Corresponding prevalence estimates for iron were much lower: 4% for inadequate intakes based on US FNB EAR vs. 8.7% for iron deficiency anaemia (haemoglobin < 110 g l-1; ferritin < 12 microg l-1) and 32.3% for low storage iron. Prevalence of inadequacy for protein was 100% for adjusted intakes and 91% for serum albumin < 32 g l-1. For calcium, 74% were at risk for inadequate intakes. CONCLUSION: The high prevalence of inadequate intakes of zinc and protein was reasonably consistent with those based on biochemical measures. Such dietary deficits could be overcome by regular consumption of cellular animal protein. In contrast, both dietary and biochemical measures of iron inadequacy were low.     

Impact of the heatwave in 2003 on the summer CH4 budget of a spruce forest with large variation in soil drainage: A four‐year comparison (2001–2004)

Well‐aerated soils are sinks for atmospheric methane (CH₄) whereas hydromorphic soils act as sources. Both CH₄ oxidation and production are highly sensitive to variation in soil moisture. Significant changes of net CH₄ fluxes from soils can therefore be expected to accompany redistribution of precipitation in the course of climate change where more extreme events are predicted for the future. The extreme summer drought in 2003 offered the opportunity to study the impact of such events on methane fluxes under field conditions. The objective was to evaluate the impact of the summer drought in 2003 on net methane budget of a spruce‐forest ecosystem. We studied net CH₄ flux (bi‐)weekly during the summers of 2000–2004 using a closed‐chamber technique on six different soil types ranging from well‐aerated Cambisols, to poorly drained Gleysols and a wet Histosol in a cool‐humid spruce forest.     

Comparison of direct benthic flux to ebullition-facilitated flux of polycyclic aromatic hydrocarbons and heavy metals measured in the field

Journal of Soils and Sediments - No studies to date have compared directly the ebullition-facilitated organic and metal contaminant fluxes to direct benthic contaminant fluxes measured in the...     

Economic and Risk Effects of Rotation Based on a 14-Year Irrigated Potato Production Study in Manitoba

Crop rotations can be used to optimize economic return by preserving or enhancing soil quality and reducing pest pressure. A field experiment consisting of six rotations of potato with canola (P-C), wheat (P-W), canola-wheat (P-C-W), oat-wheat (P-O-W), wheat-canola-wheat (P-W-C-W), and canola underseeded to alfalfa-alfalfa-alfalfa (P-C(A)-A-A) organized in a Randomized Complete Block Design was established on a clay loam soil in Manitoba, Canada and monitored for fourteen years to assess the relative economic performance of potato in each rotation. A stochastic budget based on returns and risk of returns trade-offs was used to determine each rotation’s profitability. While differences in average annual net income of all crops between rotations were not significant, the P-C-W rotation was the most stable. Despite the economic advantage of P-C in the first two cycles, longer P-C-W or P-C(A)-A-A rotations are recommended, as two-year rotations increase plant disease and decrease economic viability in the long run.     

Formation of mineral N (NH4+, NO3—) during mineralization of organic matter from coal refuse material and municipal sludge

In 1994, the 14 hectare plateau of a coal refuse bank in Landsweiler‐Reden (Southwest‐Germany) was covered with a mixture consisting of 80% (v/v) refuse materials, 10% (v/v) composted wood and 10% (v/v) of sewage sludge as part of a reclamation project. The amount of sludge dry matter applied was approximately 450 Mg ha⁻¹ to a depth of 2 m. The approximate amount of nitrogen (N) applied with the substrate was 20 Mg ha⁻¹ (total N). From April 1996 until November 1997, contents of mineral nitrogen and nitrogen mineralization were monitored down to a depth of 2 m. Nitrogen mineralization was monitored by means of a modified buried bag procedure using a retrievable cylindrical receptacle. The contents of NH₄⁺‐ and NO₃⁻‐N were largest at the beginning of the observation period, reaching a peak value of 650 kg ha⁻¹ in May 1996. Then, mineral N stabilized in 1997 at a level of 200 kg N ha⁻¹, with the soil profile below 150 cm contributing about 75% to this amount. Net nitrogen mineralization was characterized by the same depth distribution. Other than in surface horizons, mineralization activity at the bottom of the profile continued into 1997 with the same intensity as in 1996. Variability among replicate buried bag incubations was high (CV > 100% on several occasions). Nitrogen loss through leaching was estimated at 630 kg N ha⁻¹ over the observation period, averaging at 360 kg N ha⁻¹ a⁻¹. The reclamation procedure used in this study may have the potential to contaminate ground water in hydrologically sensitive areas.     

Trends in Water Chemistry of Acidified Bohemian Lakes from 1984 to 1995: II. Trace Elements and Aluminum

The concentrations of Al, Be, Cd, Cu, F, Fe, Mn, Pb, and Zn were monitored in five glacial lakes and one man-made lake in the southwestern part of the Czech Republic. The lakes had median pHs of 4.4 to 6.5 during 1984 to 1995. Decreases in the concentrations of Mn and Pb occurred in five acidified lakes. The concentrations of Al_T, Be, Cd, and F decreased in the four chronically acidified lakes, Zn decreased in two lakes. Concentrations of Cu and Fe remained unchanged. The decreases in Be, Mn, and Zn concentrations were proportional to the decrease in C_SA (C_SA = SO₄ ^2- + NO₃ ^-+ Cl^-); decreases in Al_T, Cd, and Pb concentrations were proportionately higher, while F was lower. The greater decrease in the Pb concentrations (61 to 79%, at a rate up to 0.15 μg L^-1yr^-1) was caused by pronounced decreases in deposition of Pb derived from mobile sources. The decrease of Al_T concentrations was dominated by a decrease in Al³⁺, whose concentration decreased by 51 to 86%. The concentrations of complexes Al(OH)²⁺, Al(OH)₂ ⁺, AlF²⁺, and AlH₃SiO₄ ²⁺ also decreased. The decrease in the concentrations of inorganic forms of Al (Al_i) compensated 65% of the decrease in C_SA. The Cd concentrations were highly variable in the years 1986 to 1988 because of variable amounts of accumulation on particles.