Vitreosity,its stability and relationship to protein content in durum wheat

High quality requirements are set on durum wheat (Triticum durum) from semolina mills and pasta producers. For the production of semolina and pasta with good cooking quality, high grain protein content and vitreosity is required. The dependency of vitreosity on protein content as well as its stability under the influence of humidity was not well investigated up to now. We (1) compared two methods to determine vitreosity, (2) investigated the relationship between vitreosity and protein content, (3) developed a method to analyze vitreosity under humidity, and (4) examined the relationship between protein content and agronomical as well as quality traits in durum wheat. The results showed that the formation of vitreous kernels greatly depends on the protein content. To evaluate the stability of vitreosity under the influence of humidity a new method was elaborated and employed to assess the durum germplasm under study. This revealed that vitreosity of a durum wheat variety depends on the potential to form vitreous kernels but also to maintain this vitreosity under the influence of humidity. Our results further show that protein content is a central trait in durum wheat that strongly influences important traits like grain yield, vitreosity, and b-value.     

Variation in gluten quality parameters of spring wheat varieties of different origin grown in contrasting environments

The aim of this study was to investigate variation in protein content and gluten viscoelastic properties in wheat genotypes grown in two mega-environments of contrasting climates: the southeast of Norway and Minnesota, USA. Twelve spring wheat varieties, nine from Norway and three HRS from Minnesota, were grown in field experiments at different locations in Norway and Minnesota during 2009–2011. The results showed higher protein content but lower TW and TKW when plants were grown in Minnesota, while the gluten quality measured as Rmax showed large variation between locations in both mega-environments. On average, Rmax of the samples grown in Minnesota was higher than those grown in Norway, but some locations in Norway had similar Rmax values to locations in Minnesota. The data showed inconsistent relationship between the temperature during grain filling and Rmax. Our results suggest that the weakening effect of low temperatures on gluten reported in this study are caused by other environmental factors that relate to low temperatures. The variety Berserk showed higher stability in Rmax as it obtained higher values in the environments in Norway that gave very weak gluten for other varieties.     

Alkylresorcinol composition allows the differentiation of Triticum spp. having different degrees of ploidy

Total alkylresorcinol (AR) content and homologue composition were assessed in whole grain flours of 15 varieties each of bread wheat, durum, spelt, emmer, and einkorn grown in four different environments. Bread wheat (761 ± 92 μg/g DM) and spelt (743 ± 57 μg/g) belonging to the hexaploid species showed higher AR concentrations than the tetraploid durum (654 ± 48 μg/g, p < 0.05), while the concentrations found in the diploid einkorn (737 ± 91 μg/g) and the tetraploid emmer (697 ± 94 μg/g) did not significantly differ from the other species. The AR content showed a remarkable heritability and, thus, seemed to be mainly determined by genetic factors. If ARs were assumed to be deposited within a specific AR-rich layer of the kernel, AR levels of all varieties would easily surpass their minimal inhibitory concentrations against fungal pathogens within this barrier layer. Although the AR carrying a C21:0 side chain was the main homologue in all species, the levels of all AR homologues and their relative composition significantly differed between hexaploid (bread wheat and spelt), tetraploid (durum and emmer) and diploid (einkorn) species. Consequently, a clear-cut differentiation of Triticum species and derived whole grain flours according to their degrees of ploidy was established based on concentrations of saturated C₁₇-, C₁₉-, C₂₁-, C₂₃-, and C₂₅-substituted ARs.     

Molecular characterization of storage proteins for selected durum wheat varieties grown in different environments

The variations of the amounts of individual high molecular weight glutenin subunits (HMW-GS), of the ratios HMW-GSy to HMW-GSx and HMW-GS to low molecular weight glutenin subunits (LMW-GS) and of protein content were evaluated for eight durum wheat cultivars in two regions using four fertilizer combinations during two successive years. All measured parameters showed significant variation with genotypes (G), environments (E) and fertilizers (F). The interaction E × G × F was highly significant for glutenin amount variation. Amongst cultivars possessing HMW-GS 20, landraces seem to better value the N-fertilizer use for the accumulation of HMW-GSy than high yielding cultivars. Both HMW-GSy to HMW-GSx and HMW-GS to LMW-GS ratios were found to be positively correlated (p < 0.05) with total protein content.     

Effect of allelic variation at the Glu-3/Gli-1 loci on breadmaking quality parameters in hexaploid wheat (Triticum aestivum L.)

Low molecular weight glutenin subunits (LMW-GS) encoded by the Glu-3 loci are known to contribute to wheat breadmaking quality. However, the specific effect of individual Glu-3 alleles is not well understood due to their complex protein banding patterns in SDS-PAGE and tight linkage with gliadins at the Gli-1 locus. Using DNA markers and a backcross program, we developed a set of nine near isogenic lines (NILs) including different Glu-A3/Gli-A1 or Glu-B3/Gli-B1 alleles in the genetic background of the Argentine variety ProINTA Imperial. The nine NILs and the control were evaluated in three different field trials in Argentina. Significant genotype-by-environment interactions were detected for most quality parameters indicating that the effects of the Glu-3/Gli-1 alleles are modulated by environmental differences. None of the NILs showed differences in total flour protein content, but relative changes in the abundance of particular classes of proteins cannot be ruled out. On average, the Glu-A3f, Glu-B3b, Glu-B3g and Glu-B3i_Man alleles were associated with the highest values in gluten strength-related parameters, while Glu-A3e, Glu-B3a and Glu-B3i_Chu were consistently associated with weak gluten and low quality values. The value of different Glu-3/Gli-1 allele combinations to improve breadmaking quality is discussed.     

Influence of allelic prolamin variation and localities on durum wheat quality

Thirty-seven varieties of a Mediterranean durum wheat collection grown in Tunisia and Spain were analysed for their allelic composition in prolamins, as well as their protein concentration, sodium dodecyl sulphate sedimentation (SDSS) test and mixograph parameters. Genotype was a greater source of variation in all measurements than locality. Uncommon high and low molecular glutenin subunits (HMW-GS and LMW-GS) were found (V and 2•• subunits at Glu-A1, 13 + 16 at Glu-B1, 5* subunit and ax allele at Glu-A3). The rare combinations 2 + 4+14 + 18 and 8 + 9+13 + 16+18 subunits at the Glu-B3 locus were found. Glu-A3ax had a positive influence on SDSS and mixograph parameters. Of all the prolamins, those that have the B-LMW-GS composition aaa (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d gave the best semolina quality. By contrast, semolina quality is poor when this same composition is associated with the Glu-A1c and Glu-B1e and even poorer when associated with the Glu-A1c and Glu-B1f. In addition, the cultivars with B-LMW-GS allelic composition aab (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d, gave high quality, whereas when associated with the Glu-A1c and Glu-B1e or with Glu-A1o and Glu-B1f, the quality was very poor.     

Influence of the cultivar,environment and management on the grain yield and bread-making quality in winter wheat

The genotype, environment and their interaction play an important role in the grain yielding and grain quality attributes. The main aim of this study was to determine the contributions of the genotype, environment and their interaction to the variation in bread-making traits. The data that were used for the analyses performed in this study were obtained from 3 locations in Poland from post-registration multi-environment trials with winter wheat in 2009 and 2010. The experimental factors were the cultivar (7 cultivars) and the crop management level (low input and high input). In the multi-environment trials, 17 traits were investigated that characterize grain, flour and dough quality. Most of the traits were affected much more strongly by environmental factors (i.e., year and location) than by genotype. The variance components revealed an especially strong effect of the year on the baking score, loaf volume and water absorption, as well a strong effect of the location on dough development and protein content. The obtained results demonstrate that the grain quality as measured by the parameters based on the protein content and quality may be substantially improved by crop management practices, especially by N fertilization level.     

Effect of high molecular weight glutenins and rye translocations on soft wheat flour cookie quality

The influence of high molecular weight glutenin subunits (HMW-GS) on wheat breadmaking quality has been extensively studied but the effect of different Glu-1 alleles on cookie quality is still poorly understood. This study was conducted to analyze the effect of HMW-GS composition and wheat-rye translocations on physicochemical flour properties and cookie quality of soft wheat flours. Alleles encoded at Glu-A1, Glu-B1 and Glu-D1 locus had a significant effect over physicochemical flour properties and solvent retention capacity (SRC) profile. The null allele for Glu-A1 locus presented the highest cookie factor observed (CF = 7.10), whereas 1BL/1RS and 1AL/1RS rye translocations had a negative influence on CF. The three cultivars that showed the highest CF (19, 44 and 47) had the following combination: Glu-A1 = null, Glu-B1 = 7 + 8, Glu-D1 = 2 + 12 and no secalins. Two prediction equations were developed to estimate soft wheat CF: one using the HMW-GS composition and the other using physicochemical flour parameters, where SRCsuc, SRC carb, water-soluble pentosans, damaged starch and protein turned out to be better CF predictors. This data suggests that grain protein allelic composition and physicochemical flour properties can be useful tools in breeding programs to select soft wheat of good cookie making quality.     

Real-time quantitative PCR based method for the quantification of fungal biomass to discriminate quantitative resistance in barley and wheat genotypes to fusarium head blight

Fusarium head blight (FHB) caused by Fusarium graminearum is one of the devastating diseases of small grain crops, including barley and wheat. Breeding for resistance is one of the best and ecofriendly strategies to manage the FHB. However, the existing methods used for screening genotypes, both under field and greenhouse conditions, often resulted in high experimental error, leading to inconsistent ranking of genotypes over years. In the postgenomic era, precise assessment of resistance is crucial to identify candidate genes. Here, we report a pathogen inoculation procedure and a real-time quantitative polymerase chain reaction (qPCR) based protocol for the quantification and discrimination of quantitative resistance among barley and wheat genotypes to FHB. Using Fusarium specific primer pair Tri6_10, for the trichothecene biosynthetic cluster (Tri6) gene, we successfully quantified the relative fungal biomass in both spikelets and rachis. A qPCR of spikelets and rachis collected on 6 dpi, from inoculated three alternate spikelet regions, discriminated resistance with less experimental error than those based on the proportion of spikelets diseased (PSD) at 9 dpi. This method can be applied for medium to high-throughput barley and wheat breeding programmes to discriminate quantitative resistance among genotypes against FHB.     

Puroindoline genes introduced into durum wheat reduce milling energy and change milling behavior similar to soft common wheats

Grain physical characteristics and milling behavior of a durum wheat line in which both wild-type puroindoline genes were translocated and stabilized after backcrossing (Svevo-Pin) were compared with the parent line (Svevo). The only observed differences between grain characteristics were the mechanical resistance and starchy endosperm porosity revealed through vitreosity measurement. A significant increase of flour and a decrease of semolina yield and break milling energy were observed from Svevo-Pin in comparison with the non-recombinant parent line in accordance to the lower grain mechanical resistance and higher porosity measurements. Moreover, the particle size distribution shown for Svevo-Pin flour appeared consistent with a lower adhesion between starch granules and the protein matrix attributed to the presence of wild-type puroindolines. Coarse bran yield was conversely increased. This appeared to be due to a lower starchy endosperm recovery as a higher proportion of grain starch was found in this bran fraction. Flour from the durum parent line was inversely enriched in phytic acid, a cellular marker of the aleurone layer. Starch damage was also lower in Svevo-Pin flours in comparison with Svevo. All of the observed differences between translocation and parent lines were confirmed independent of the culture growth conditions (n = 12).     

Formulating low glycaemic index rice flour to be used as a functional ingredient

Amylose and resistant starch (RS) content in rice flour were manipulated. The experiment was conducted using a full factorial design. Rice flour with average amylose content of 20 and RS content of 0.5 g/100 g dry sample was fortified with pure amylose from potato and high RS modified starch to reach the final amylose content of 30, 40 and 50 and RS content of 2, 4 and 6 g/100 g dry sample. The fortified rice flours were examined for their gelatinisation properties, in-vitro enzymatic starch digestion and gel textural properties. It was found that amylose and RS significantly affect all the fortified rice flour properties (p < 0.05). High amylose and RS improved starch digestion properties, reducing the rate of starch digestion and lowering the glycaemic index (GI) values. Amylose had a more pronounced effect on the fortified rice starch properties than RS. In this study, the fortified rice flour which contained amylose and RS of approximately 74 and 9 g/100 g dry sample respectively was used to produce rice noodles. The noodles exhibited low GI values (GI < 55). However, amylose and RS affected the textures of rice noodles providing low tensile strength and break distance (extensibility).     

Suitability of tef varieties in mixed wheat flour bread matrices: A physico-chemical and nutritional approach

Wheat flour replacement from 0 to 40% by single tef flours from three Ethiopian varieties DZ-01-99 (brown grain tef), DZ-Cr-37 (white grain tef) and DZ-Cr-387 (Quncho, white grain tef) yielded a technologically viable ciabatta type composite bread with acceptable sensory properties and enhanced nutritional value, as compared to 100% refined wheat flour. Incorporation of tef flour from 30% to 40% imparted discreet negative effects in terms of decreased loaf volume and crumb resilience, and increase of crumb hardness in brown tef blended breads. Increment of crumb hardness on aging was in general much lower in tef blended breads compared to wheat bread counterparts, revealing slower firming kinetics, especially for brown tef blended breads. Blended breads with 40% white tef exhibited similar extent and variable rate of retrogradation kinetics along storage, while brown tef-blended breads retrograded slower but in higher extent than control wheat flour breads. Breads that contains 40% tef grain flour were found to contain five folds (DZ-01-99, DZ-Cr-387) to 10 folds (DZ-Cr-37) Fe, three folds Mn, twice Cu, Zn and Mg, and 1.5 times Ca, K, and P contents as compared to the contents found in 100% refined wheat grain flour breads. In addition, suitable dietary trends for lower rapidly digestible starch and starch digestion rate index were met from tef grain flour fortified breads.     

Improved functional properties of pasta: Enrichment with amaranth seed flour and dried amaranth leaves

The present investigation evaluated the effects of dried amaranth leaves (DAL) and amaranth seed flour (AF) as ingredients for pasta production and their contribution to antioxidant activity. Cooking quality, proximal and aroma analysis, antioxidant capacity and sensory evaluations were performed. The results demonstrated that pastas with amaranth ingredients had decreased cooking time, increased cooking loss percentage, and decreased luminosity values compared with semolina control pasta. Pastas with both AF and DAL demonstrated the highest protein, crude fiber and ash contents. The addition of DAL resulted in higher contents of iron, zinc, magnesium and potassium compared with the control pasta. TC, FRAP and ORAC assays showed that the pastas exhibited an important reduction in antioxidant capacity by cooking process. Formulas with DAL showed the higher antioxidant capacity values after cooking. The addition of AF and DAL has proved to increase the functional benefits of the pasta.     

Effects of drought on the morphological and physicochemical characteristics of starch granules in different elite wheat varieties

In this study, scanning electron microscopy (SEM) revealed the formation of pits and pores on the surfaces of starch granules in response to drought stress, with substantially more pronounced effects in the ordinary yield potential wheat cv. Xindong 23 than the excellent yield potential wheat cv. Xindong 20. Drought induced a significant reduction in starch granule sizes in both wheat varieties, though the reduction observed in Xindong 23 was six times more pronounced than that observed for Xindong 20. Amyloglucosidase and α-amylase treatment of starch from wheat grown in drought conditions released significantly more reducing sugars compared with samples from irrigated controls. SEM and confocal laser scanning microscopy (CLSM) revealed that starch granules from the two wheat varieties grown under drought conditions had substantially increased fluorescence after treatment with proteolytic enzymes and staining with methanolic merbromin and 3-(4-carboxybenzoyl) quinoline-2-carboxaldehyde dyes. Analysis of pasting properties showed significant increases of peak viscosity, trough viscosity, break down, and setback following drought stresses. Furthermore, drought induced a significant reduction in the water binding capacity and increased damage to starch only in Xindong 23. These results provide insight into the potential mechanisms through which drought influences the ultrastructures and physicochemical properties of starch in wheat.     

Characterisation of starch during germination and seedling development of a rice mutant with a high content of resistant starch

To acquire a better understanding of whether RS influences the dynamics of in vivo starch digestion and seed vigour, the high-RS rice mutant RS4 (RS ca. 10%) and the wild type R7954 were used to investigate total amylase activity, seedling vigour, starch content and starch granule structure during germination. RS4 exhibited similar seed vigour to R7954. Amylose and amylopectin in R7954 showed synchronous degradation throughout the whole process, while amylopectin was hydrolysed significantly faster than amylose in RS4 during the earlier germination stages. The starch residues of RS4 after germination (GD) lost endotherm peaks and showed a special X-ray diffraction pattern with only two peaks at around 16.90° and 21.62°, probably due to remnants of amylopectin and its tight crosslinking with the cell wall. The remaining starch after 10 GD, primarily amylopectin may make a critical contribution to total resistant starch content. These results indicated that RS had no negative impact on seed vigour in rice lines, although RS cannot be hydrolysed by α-amylase from human and animal in vitro. By appropriately increasing the special amylopectin fraction, a new breeding programme of high RS crops and improvement in the eating quality of high RS rice varieties might be achieved.     

Predicted truly absorbed protein supply to dairy cattle from hulless barley (Hordeum vulgare L.) with altered carbohydrate traits with multi-year samples

Hulless barley breeding lines varying in amylose (1–20% DM) and β-glucan content (5–10% DM) have been developed at the Crop Development Centre, Canada. The objectives of this large-scale study were to 1) determine and confirm the effect of these new hulless barley lines (zero-amylose waxy, CDC Fibar; 5%-amylose waxy, CDC Rattan; normal-amylose, CDC McGwire and high-amylose, HB08302) with altered carbohydrate traits on 1) metabolic characteristics of protein; 2) intestinal digestion of various nutrients and 3) modeling nutrient supply from these barley varieties by using NRC Dairy 2001 model and DVE/OEB system. CDC Copeland was included as a hulled barley control. Among the hulless barley lines, CDC Fibar contained the highest and CDC McGwire contained the lowest total digestible protein (TDP: 147 vs. 116 g/kg DM). HB08302 was greater (P < 0.05) in intestinal digestible protein (IDP: 40.6% RUP) but relatively lower (P < 0.05) in total digestible protein (TDP: 120 g/kg DM). Compared with hulless barley, hulled barley showed relatively lower (P < 0.05) intestinal digestible protein (38 vs. 53 g/kg DM) and total digestible protein (102 vs. 129 g/kg DM). In modeling nutrient supply from the DVE/OEB system, the results showed hulled barley was lower (P < 0.01) in true protein supplied to the small intestine (TPSI: 127 vs. 142 g/kg DM), lower in truly absorbed rumen bypassed feed protein in small intestine (ABCP^DVE: 43 vs. 58 g/kg DM), lower in truly absorbed protein in the small intestine (DVE: 95 vs. 111 g/kg DM), and lower in degraded protein balance (OEB^DVE: −39 vs. −23 g/kg DM) than the hulless barley lines but greater (P < 0.01) in undigested inorganic matter (9 g/kg DM). From NRC Dairy 2001 model, CDC Fibar was greater (P < 0.05) in degraded protein balance (OEB^NRC: −30 g/kg DM) and metabolizable protein (MP: 118 g/kg DM) than the other hulless barley lines, while hulled barley was relatively lower (P < 0.01) in total metabolizable protein (MP: 83 vs. 105 g/kg DM). Our correlation results suggested that TDP was negatively correlated to amylose (r = −0.85, P < 0.001) but positively correlated to β-glucan level (r = 0.74, P < 0.001) in hulless barley cultivars. The DVE and OEB^DVE as well as MP were negatively correlated (P < 0.05) to amylose level but positively correlated to β-glucan level (P < 0.05). In conclusion, altered carbohydrate traits in the hulless barley varieties have the potential to increase intestinal nutrient availability to ruminants and significantly improved the truly absorbed protein supply to dairy cattle compared to hulled barley. Hulless barley with lower amylose and higher β-glucan level could provide greater (P < 0.05) truly digested protein in the small intestine, better synchronized available energy and N and increase metabolizable protein supply to ruminants.     

The molecular structure features-immune stimulatory activity of arabinoxylans derived from the pentosan faction of wheat flour

Recently, the immune stimulation properties of cereal arabinoxylans (AX) have been reported. The aims of this study were to identify the molecular features and potential immune stimulation activities of AX and enzymatic modified arabinoxylan (AXE) from the pentosan fraction of wheat flour.The results of molecular characterization of AX and AXE show that AXE contains a larger portion (85.7%) of low Mw arabinoxylans (≤25 kDa) and has a higher degree of branch substitution (0.81 ± 0.01) compared to AX (49.5% and 0.62 ± 0.02). In in vitro testing, the ability of AX and AXE to stimulate immune cells, as measured by NO₂⁻ production by U937 cells and IL-8 secretion by Caco-2 cells were found to be dose–dependent in the range tested (100–5000 μg/mL p ≤ 0.05). AXE showed a greater activity at each concentration (100–5000 μg/mML) than AX (p ≤ 0.05).In conclusion, the greater immune stimulating activity of AXE may be associated with its low Mw (≤25 kDa) and a higher degree of branch substitution (0.81 ± 0.01).     

In vitro starch digestibility and predicted glycaemic indexes of buckwheat,oat, quinoa,sorghum, teff and commercial gluten-free bread

The in vitro starch digestibility of five gluten-free breads (from buckwheat, oat, quinoa, sorghum or teff flour) was analysed using a multi-enzyme dialysis system. Hydrolysis indexes (HI) and predicted glycaemic indexes (pGI) were calculated from the area under the curve (AUC; g RSR/100g TAC*min) of reducing sugars released (RSR), and related to that of white wheat bread. Total available carbohydrates (TAC; mg/4 g bread “as eaten”) were highest in sorghum (1634 mg) and oat bread (1384 mg). The AUC was highest for quinoa (3260 g RSR), followed by buckwheat (2377 g RSR) and teff bread (2026 g RSR). Quinoa bread showed highest predicted GI (95). GIs of buckwheat (GI 80), teff (74), sorghum (72) and oat (71) breads were significantly lower. Significantly higher gelatinization temperatures in teff (71 °C) and sorghum flour (69 °C) as determined by differential scanning calorimetry (DSC) correlated with lower pGIs (74 and 72). Larger granule diameters in oat (3–10 μm) and sorghum (6–18 μm) in comparison to quinoa (1.3 μm) and buckwheat flour (3–7 μm) as assessed with scanning electron microscopy resulted in lower specific surface area of starch granules. The data is in agreement with predictions that smaller starch granules result in a higher GI.     

Effects of post-anthesis fertilizer on the protein composition of the gluten polymer in a US bread wheat

Both genetic and environmental factors influence the types and amounts of wheat proteins that link together to form polymers essential for flour quality. To understand how plant growth conditions might influence gluten polymer formation, protein fractions containing small and large polymers were separated from flour from the US wheat Butte 86 grown in the absence or presence of post-anthesis fertilizer. Proteins in the polymer fractions were analyzed by quantitative two-dimensional gel electrophoresis (2-DE). The ratio of high molecular weight glutenin subunits (HMW-GS) to low molecular weight glutenin subunits (LMW-GS) increased in both fractions in response to fertilizer, due in part to small increases in the proportions of individual HMW-GS. There were also changes within the LMW-GS. In particular, omega and alpha chain terminators increased in proportion in both polymer fractions, but changes were more pronounced in the large polymer fractions. Serpins also increased in both polymer fractions. Additionally, the study revealed differences in the proportions of traditional LMW-GS in small and large polymer fractions. LMW-s type proteins were more abundant in the large polymers while LMW-i type proteins were more prevalent in the small polymers, suggesting that these proteins may play different roles in the gluten polymer.