Relationship between lutein and mycotoxin content in durum wheat

Levels of lutein and a number of mycotoxins were determined in seven varieties of durum wheat (Triticum durum) and two varieties of common wheat (Triticum aestivum) in order to explore possible relationships amongst these components. Durum wheat cultivars always showed both higher lutein and mycotoxin contents than common wheat cultivars. The mycotoxins detected in both common and durum wheat cultivars were produced by the genera Fusarium, Claviceps, Alternaria and Aspergillus. Fusarium was the major producer of mycotoxins (26 mycotoxins) followed by Claviceps (14 mycotoxins), which was present only in some cultivars such as Chevalier (common wheat), Lupidur and Selyemdur (both durum wheat), Alternaria (six mycotoxins) and Aspergillus (three mycotoxins). Positive correlations between the levels of lutein and mycotoxins in durum wheat cultivars were found for the following mycotoxins: deoxynivalenol (DON), its derivative DON-3-glucoside, moniliformin, culmorin and its derivatives (5-hydroxyculmorin and 15-hydroxyculmorin).     

Agglomeration of durum wheat semolina: Thermodynamic approaches for hydration properties measurements

In the manufacturing process of pasta or couscous, durum wheat semolina agglomeration comprises successive steps, in particular a wetting and hydration stage. In this step, interactions between water molecules and semolina grains contribute to the agglomeration properties. Hydration properties of semolina have been recognised to play an important role in agglomeration.The hydration properties of semolina have been characterised using various methods which can be divided into 2 groups according to the water addition: liquid or vapour. Several parameters can be used to describe hydration properties and hydration mechanisms, such as: water sorption capacity, hydration kinetics, diffusion of water within the solid (swelling, dissolution, solid-water affinity and thermodynamic properties).In this study, sorption isotherms and diffusion coefficients have been determined by gravimetric method in specific conditions. The immersion enthalpy of the semolina and its main sub-components, starch and gluten have been measured by mixing micro-calorimetry. Hydration thermodynamic properties, Gibbs free energy, enthalpy and entropy, were calculated from these experimental data. It was found that hydration by vapour or liquid water is an exothermic reaction.The determined diffusion coefficient was used to estimate the stabilisation time of water within the solid. Being high at low relative humidity, the diffusion coefficient decreases during progressive saturation of solid sites. Sorption energy and solid-water affinity yield information about the type of interaction between water molecules and solid sites. The drop in the sorption energy during the increase in water content can be attributed to a decrease in solid-water interactions. The hydration energy of durum wheat semolina in vapour or liquid water was found to be low. This corresponds to the energy input needed to generate contact between water and grain surface and for mixture homogenisation.     

Amino acid composition of two Italian durum wheat varieties and their semolina

Two Italian durum wheat varieties and their semolina were analysed for protein content and amino acid composition. There was a difference in protein content between the two varieties. The concentration (in protein) of lysine, methionine and phenyl alanine was equal in both varieties. A large difference was found in glutamic acid and valine. A slight difference was found in other amino acids. There was a difference in the concentration of amino acids between wheat and its semolina. The biological value was equal in both varieties. The difference in results is attributed to the varietal difference.     

A study on relationships between durum wheat semolina properties,technological mixing parameters and the properties of dough after mixing

Partial least square regression analysis was used to study the correlation between X variables (semolina quality, hydration level and mixing time) and Y variables, which were, in a first model, dough consistency during mixing, and, in a second model, dough properties after mixing (strength, elasticity, density) and leavening (maximum volume). The first model showed a predictive residual sum of squares (PRESS) of 2.98 and a predictive R² (Q²) of 0.92, and highlighted the key role of hydration and mixing time on dough consistency. The second model had the best PRESS (8.25) and Q² (0.94) values for dough volume and indicated that the volume increased with increasing mixing time until the dough consistency decreased of 20–30%. Dough volume was primarily affected by hydration. The model indicated that maximum volume after leavening, corresponding to optimum mixing time, was obtained with a soft and elastic dough, with a low‐density value.     

Microstructure,textural and sensorial properties of durum wheat bread as affected by yeast content

In this study, breads varying in yeast content and therefore leading to distinct cellular structures are investigated. Firstly, X-ray microtomography is used to characterize not only the final cellular structure, but also the process of development of microstructure during the fermentation stage. With μCT, image analysis of the full 3-D microstructure, measuring the size, shape, networking/connectivity and distribution of various phases was possible. These measurements represent the full 3-D microstructure, which is not always possible by 2-D image analysis using statistical techniques. Secondly, the textural properties of the baked bread were obtained by compression tests and finally, the sensorial quality of the final product is also evaluated and correlated with the above properties. Results showed that an increase of the yeast content increased the percentage volume of pores and decreased the force required for compression of the bread sample and the tenacity. Moreover, a larger quantity of smaller sized pores led to a firmer bread structure. Regarding the sensorial properties, none of the investigated microstructural parameters were significantly correlated with the overall quality of the bread. In fact, the overall quality was more strongly affected from other parameters such as odor and appearance attributes.     

Commercial pasta manufacture: Changes in lipid binding during processing of durum wheat semolina

Summary The quantities of total free (hexane-extractable) and bound (extracted by hot water-saturated butanol but not hexane) acyl lipids have been determined in durum wheat semolina and pasta and at intermediate stages during pasta manufacture. Semolina contained approximately equal amounts of free and bound lipids, but about 90% of the free lipid became bound during processing, especially during the drying stages. The triacylglyceride fraction exhibited a similar binding during the process and this fraction probably accounts for much of the binding observed.

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Kommerzielle Erzeugung von Teigwaren: Änderung der Lipidbindung während der Verarbeitung von Durum-Weizengrieß

Zusammenfassung Die Gesamtmengen der freien (mit Hexan extrahierbaren) und gebundenen (heiß mit wassergesättigtem Butanol, über nicht mit Hexan extrahierbaren) Acyllipide in Durum-Weizengrieß, in Teigwaren und in den Zwischenstufen sind bestimmt worden. Der Grieß enthielt etwa gleiche Mengen freier und gebundener Lipide, über während der Verarbeitung, insbesondere bei den Trockenvorgängen, wurden etwa 90% der Lipide gebunden. Die Triglycerid-Fraktion zeigte während der Verarbeitung eine ähnliche Bindung, und ein großer Anteil der beobachteten Bindung ist wahrscheinlich auf diese Fraktion zurückzuführen.

     

Rheological,microstructural and sensorial properties of durum wheat bread as affected by dough water content

In this paper the influence of water content on the rheological, microstructural and sensorial properties of durum wheat bread was evaluated. In order to evaluate bread quality, oscillation measurements, stress relaxation test and creep–recovery measurements were performed on dough samples, whereas tomographic and sensorial analyses were performed on baked bread samples. Results of the rheological analysis highlighted that both the storage and loss moduli (G′, G″) showed a descending trend with the increase of the water content. This is also confirmed by stress relaxation tests. Creep–recovery tests for strong doughs (with low water content), recorded greater resistance to deformation, therefore a smaller creep strain than the softer doughs. These results were reflected in the microstructural properties of the bread; an increase in water content caused an increase in the percentage volume of pores. Regarding the sensorial properties, the overall acceptability of the investigated bread samples was low for both the lowest and the highest water contents, and this was due primarily to the compact crumb with small bubbles and high crust firmness for the former and to the loaf volume collapsed with irregular distribution of very large bubbles for the latter. Therefore, the bread samples with intermediate water content were preferred by the panelists.     

In-line monitoring of durum wheat semolina wet agglomeration by near infrared spectroscopy for different water supply conditions and water addition levels

The aim of this work is (i) to study the ability of near infrared (NIR) spectroscopy to follow in-line the agglomeration process of durum wheat semolina using mechanical mixer according to two different water supply conditions (i.e. high versus low water flow rates) and to four different water addition levels, and (ii) to describe the associated structural changes of agglomerates. The results showed that analyses of spectral variations can be useful to discriminate different agglomeration processes, which are associated to different kinetic changes in terms of agglomerate size distribution and water content per size fraction. Principal component analysis (PCA) has been used to qualitatively describe physical and chemical variations occurring during the wet agglomeration mechanisms and to identify specific kinetics and characteristic times. Whatever the water supply condition, kinetic variations of principal components (PCs) on raw and second derivative NIR spectra are observed. Characteristic times have been identified on PC scores and an attempt to link these times to changes of agglomerates physical and chemical properties have been carried out, mainly based on the analysis of associated loading spectra.     

Fusarium mycotoxin content of UK organic and conventional wheat

Each year (2001–2005), 300 samples of wheat from fields of known agronomy were analysed for ten trichothecenes by gas chromatography-mass spectrometry (GC/MS) including deoxynivalenol (DON), nivalenol, 3-acetyl-DON, 15-acetyl-DON, fusarenone X, T2 toxin, HT2 toxin, diacetoxyscirpenol, neosolaniol and T-2 triol and zearalenone by high-performance liquid chromatography (HPLC). Of the eleven mycotoxins analysed from 1624 harvest samples of wheat, only eight were detected, and of these only five–deoxynivalenol, 15-acetyl-DON, nivalenol, HT-2 and zearalenone–were detected above 100 µg kg^?1. DON was the most frequently detected Fusarium mycotoxin, present above the limit of quantification (10 µg kg^?1) in 86% of samples, and was usually present at the highest concentration. The percentage of samples that would have exceeded the recently introduced legal limits varied between 0.4% and 11.3% over the five-year period. There was a good correlation between DON and zearalenone concentrations, although the relative concentration of DON and zearalenone fluctuated between years. Year and region had a significant effect on all mycotoxins analysed. There was no significant difference in the DON concentration of organic and conventional samples. There was also no significant difference in the concentration of zearalenone between organic and conventional samples, however organic samples did have a significantly lower concentration of HT2 and T2. Overall, the risk of UK wheat exceeding the newly introduced legal limits for Fusarium mycotoxins in cereals intended for human consumption is low, but the percentage of samples above these limits will fluctuate between years.     

Distribution of toxigenic Fusarium spp. and mycotoxin production in milling fractions of durum wheat

A reliable and sensitive PCR assay to specifically detect trichothecene-producing Fusarium spp. in milling fractions and kernel tissue of naturally infected durum wheat is reported. Assays were based on a combination of primers derived from the trichodiene synthase and the β-tubulin genes. The occurrence of toxigenic Fusarium spp. in semolina and wheat tissue (grain ends, crease, pericarp, aleurone layer, germ and albumen) was detected, even for a weakly contaminated wheat sample. Penetration of toxigenic Fusarium spp. into the interior of durum wheat kernel was demonstrated for the Nefer variety, indicating that none of the tissue structures within the wheat kernel acted as an effective barrier to fungal invasion. Moreover, after inoculation by toxigenic Fusarium strains, semolina was shown to allow high yields of trichothecenes, while bran was demonstrated to contain biochemical inhibitors able to significantly reduce trichothecene production. These results will be useful in improving breeding strategies to control trichothecene contamination of durum wheat kernels.     

Amylose content and starch properties in emmer and durum wheat lines with different waxy proteins composition

BACKGROUND: Emmer wheat is a neglected crop that can be used in the breeding of modern durum wheat for quality. One important aspect of this quality is the starch composition, which is related to the waxy proteins. A collection of emmer wheat was analysed previously for waxy protein composition, and two new Wx‐B1 alleles were found by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and DNA sequencing analysis. It is necessary to analyse the effect of these alleles in starch properties and compare them to durum wheat ones. RESULTS: In the current study, emmer lines carrying three different Wx‐B1 alleles (Wx‐B1b, ‐B1g, ‐B1c*), including one with the null allele (Wx‐B1b), together with durum cultivars Langdon (Wx‐B1a) and Mexicali (Wx‐B1c′), were analysed for amylose content. Differences were detected between both species, and the line lacking Wx‐B1 protein showed a remarkably low amylose content. In addition, data from blue value, swelling power and Rapid Visco Analyzer also suggested that there were differences in starch properties among the different Wx‐B1 alleles. CONCLUSION: The present study suggests that the amylose content in emmer (Wx‐B1g) and durum (Wx‐B1a) standard materials is not the same; therefore some starch properties are different between the two species. The variation found could be used to enlarge the gene pool of durum wheat and design new materials with desirable amylose content. Copyright © 2011 Society of Chemical Industry     

Protein content and gluten quality of durum wheat (Triticum turgidum subsp. durum) as affected by sowing date

The end use quality of durum wheat is sensitive to the environmental conditions pertaining before and during grain filling, and can therefore be modified by manipulation of cultivar and sowing date. A field trial was carried out to study the effect on protein content and gluten quality of varying both sowing date (October, December and March) and cultivar (Simeto, Colosseo and Creso). A delay in sowing date was associated with a decrease in mean grain weight, but not in grain nitrogen content, thus leading to an overall increase from 10.7 to 14.7% in grain protein percentage. Independent of sowing date, over 78% of the grain nitrogen was derived from re‐translocation from vegetative tissue. The similar amounts of nitrogen accumulated in each grain at maturity were set by the similarity in the amount of nitrogen available at anthesis. The observed increase in protein percentage partly explained the greater dough strength (alveographic W) observed in material harvested from the latest sowing. The gluten index, on the other hand, decreased as sowing was delayed. Given the parallel increase in glutenin percentage, we propose that temperatures above 30 °C at the end of the grain filling period have a negative effect on the gluten polymerisation process. Copyright © 2007 Society of Chemical Industry     

Environmental conditions affect semolina quality in durum wheat (Triticum turgidum ssp. durum L.) cultivars with different gluten strength and gluten protein composition

BACKGROUND: Sowing time may impact semolina and pasta cooking quality by changing the environmental conditions during grain filling. The effect of an optimum and a delayed sowing time on semolina quality was studied by comparing six cultivars under irrigation, in order to isolate temperature from drought effects. RESULTS: Protein content was higher in the old cultivars and in the late sowings, according to the number of days with temperature between 30 and 40 °C during ripening. Gluten index increased as temperature rose to a threshold of about 30 °C, then decreased under higher temperatures. Mixograph parameters were less sensitive to high temperatures. Gliadin:glutenin correlated with gluten strength. Spaghetti firmness and protein content were positively correlated independently of sowing date. Cultivars Trinakria and Cappelli had the highest spaghetti firmness (900 and 828 g). CONCLUSIONS: Late sowings may represent a way of increasing pasta cooking quality whenever they place grain filling under thermal conditions able to increase protein percentage, although the accompanying decrease in yield may represent a drawback in environments prone to drought stress during ripening. The lower protein percentages of modern durum wheat cultivars under conventional sowing times results in a lower pasta cooking quality despite higher gluten strength. Published 2011 by John Wiley & Sons, Ltd.     

紫外线辐射处理的羊毛染色性能研究

采用紫外线辐射处理羊毛 ,通过X射线光电子能谱仪分析了处理前后纤维表面的化学变化。研究结果表明紫外线处理使羊毛纤维鳞片表层的胱氨酸氧化 ,二硫键断裂。未处理和经紫外线处理 6 0min的羊毛 ,分别在不同温度 4 5℃ ,5 0℃ ,5 5℃和 6 0℃染色。实验显示 ,处理后的纤维上染速率提高 ,染色K S值增加 ,表明紫外线辐射处理改善了羊毛纤维的染色性能。此外 ,在研究了处理前后纤维的染色吸附和扩散性能后 ,发现处理后纤维染色扩散系数提高 ,染色吸附性能不变。紫外线处理破坏了羊毛纤维鳞片表层二硫键形成的致密的网状结构 ,使羊毛的初始染色壁障被打破 ,染料容易从染浴向纤维内扩散。     

Sorption and desorption of sulfuryl fluoride by wheat,flour and semolina

Sulfuryl fluoride (SF) has been developed as a fumigant for control of insect pests in stored grain. However, there is very limited information on the sorption behaviour of this fumigant, which can be critical to its bioactivity, application and potential for residues. We undertook a comprehensive laboratory study of the sorption and desorption of SF by wheat (bread and durum), flour and semolina at 15, 25 and 35 °C, moisture contents 12% and 15%, and concentration × time combinations at CT = 1500 mgh/L (4.167 mg/L × 360 h, 8.928 mg/L × 168 h and 31.25 mg/L × 48 h).At each dosage, sorption rate increased as commodity temperature and moisture content increased. The highest rates of sorption occurred at 35 °C and 15% m.c., and lowest rates at 15 °C and 12% m.c., and the rate was independent of initial concentration. Sorption followed first order reaction kinetics described by the exponential decay equation, C_t = C₀·e^−k*t, where k is the sorption rate constant. The most important factors determining the rate of sorption were commodity particle size (exposed surfaces) and temperature. Little sorption of fumigant occurred within the first 24 h whereas longer fumigation times resulted in significant sorption. Unbound SF was rapidly lost from the commodity upon aeration with no further desorption detected under any of the test conditions.SF possesses a number of characteristics that recommend it as a commodity fumigant. It is sorbed slowly by commodities relative to methyl bromide and carbonyl sulphide although it is sorbed about 4–5 times faster than phosphine. It desorbs rapidly upon aeration, and the lack of continued desorption has practical workplace health and safety benefits. On the other hand, sorbed SF appears irreversibly bound to the commodity matrix indicating the need to be alert to the possibility of excessive residues, particularly in longer term fumigations.     

High Performance Index as a tool to identify the best combination of pearled fractions and durum wheat genotypes for semolina and pasta colour improvement

Debranning was applied to six durum wheat genotypes to identify specific fractions rich in carotenoids and lower in enzymatic activities useful for improving pasta colour. Six sequential debranning steps, each of 30 s, were applied. β-carotene, lutein, α-tocopherol and ash content and hydroperoxidation and bleaching activities of lipoxygenase were determined in all pearled fractions. A wide variability among the genotypes regarding the level of all components has been found. Most of the parameters were higher in the pearled fraction at 30 s than wholemeal. Compared to the latter fraction, a significant decreasing trend for both lipoxygenase activities and α-tocopherol and ash content was subsequently observed, while β-carotene decreased more slightly. Lutein content remained quite stable in all subsequent pearled fractions. The pearled fraction of the Ofanto obtained at 90 s of debranning was identified as the best genotype/pearled fraction combination through our High Performance Index tool.     

Physicochemical properties and silicon content in wheat flour treated with diatomaceous earth and conventionally stored

This study was done to evaluate the physicochemical properties and to quantify the residual silicon in flour from wheat grains treated with different dosages of DE and stored in a conventional system for 180 days. Samples containing 10.0 kg of wheat grain were treated with 0.00, 2.00 and 4.00 g kg⁻¹ of DE and then homogenized and stored in cotton bags at 22 °C and 70 ± 5 g 100 g⁻¹ relative humidity. Physicochemical analyses were carried out at 0, 60, 120 and 180 days of storage. The experiment was conducted in a randomized design with a factorial 3 × 4 arrangement (three doses of DE × four storage periods), totaling 12 treatments, with three replicates for each treatment. The wheat flour samples were digested and the silicon residue quantification was conducted through colorimetry. The wheat treated with DE presented a lower test weight compared with control, +b^∗ chromaticity coordinate for color and increased ash content and L^∗. The physicochemical changes in the grain and wheat flour were proportional to the amount of DE applied.