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).     

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.     

Combined mutations in five wheat STARCH BRANCHING ENZYME II genes improve resistant starch but affect grain yield and bread-making quality

Increases in the proportion of amylose in the starch of wheat grains result in higher levels of resistant starch, a fermentable dietary fiber associated with human health benefits. The objective of this study was to assess the effect of combined mutations in five STARCH BRANCHING ENZYME II (SBEII) genes on starch composition, grain yield and bread-making quality in two hexaploid wheat varieties. Significantly higher amylose (∼60%) and resistant starch content (10-fold) was detected in the SBEII mutants than in the wild-type controls. Mutant lines showed a significant decrease in total starch (6%), kernel weight (3%) and total grain yield (6%). Effects of the mutations in bread-making quality included increases in grain hardness, starch damage, water absorption and flour protein content; and reductions in flour extraction, farinograph development and stability times, starch viscosity, and loaf volume. Several traits showed significant interactions between genotypes, varieties, and environments, suggesting that some of the negative impacts of the combined SBEII mutations can be ameliorated by adequate selection of genetic background and growing location. The deployment of wheat varieties with increased resistant starch will likely require economic incentives to compensate growers and millers for the significant reductions detected in grain and flour yields.     

Preparation of protein and mineral rich fraction from grain amaranth and evaluation of its functional characteristics

Grain amaranth was fractionated to prepare a seed coat rich fraction along with the fine seed coat, middling and flour fractions. The nutritional content of the coarse seed coat fraction and its antioxidant potential were evaluated. It was observed that, the coarse seed coat fraction contained highest protein (17.81 g/100 g), dietary fiber (25.78 g/100 g), free sugar (2.25 g/100 g), calcium (1115 mg/100 g), sodium (279 mg/100 g), magnesium (178.4 mg/100 g) and potassium (398.8 mg/100 g) contents compared to all other fractions. The carbohydrate and protein digestibility of all the fractions were more than 80%. A slight decrease in linoleic acid and a concurrent increase in palmitic acid contents were observed in coarse seed coat fraction. The total phytic acid increased and total polyphenols contents decreased in the coarse seed coat fraction compared to the native grain. The DPPH, ABTS and total antioxidant activities are comparatively high in this particular fraction. The study indicated a possibility of preparation of a protein, fiber and mineral rich fraction from grain amaranth with good antioxidant potential which can be used as a functional food ingredient.     

Breeding for increased grain protein and micronutrient content in wheat: Ten years of the GPC-B1 gene

To provide food and nutrition security for a growing world population, continued improvements in the yield and nutritional quality of agricultural crops will be required. Wheat is an important source of calories, protein and micronutrients and is thus a priority to breed for improvements in these traits. The GRAIN PROTEIN CONTENT-B1 (GPC-B1) gene is a positive regulator of nutrient translocation which increases protein, iron and zinc concentration in the wheat grain. In the ten years since it was cloned, the impacts of GPC-B1 allelic variation on quality and yield traits have been extensively analyzed in diverse genetic backgrounds in field studies spanning forty environments and seven countries. In this review, we compile data from twenty-five studies to summarize the impact of GPC-B1 allelic variation on fifty different traits. Taken together, the results demonstrate that the functional copy of the GPC-B1 gene is associated with consistent positive effects on grain protein, Fe and Zn content with only marginally negative impacts on yield. We conclude that the GPC-B1 gene has the potential to increase nutritional and end use quality in a wide range of modern cultivars and environments and discuss the possibilities for its application in wheat breeding.     

Effects of non-chemical soil fumigant treatments on root colonisation with arbuscular mycorrhizal fungi and strawberry fruit production

The effects of biofumigation and soil heating on arbuscular mycorrhizal fungi (AMF) colonisation, strawberry growth and strawberry yield in pot experiments compared with untreated soil and chemical fumigation with dazomet were tested. Three different Brassicaceae species (Brassica juncea, Eruca sativa, Sinapis alba) were used as biofumigant plant green manure and soil heating was applied to simulate soil solarisation. Half of the plants were inoculated with indigenous arbuscular mycorrhizal fungi inoculum. With one exception (E. sativa) among the uninoculated plants, the treatments significantly decreased the mycorrhizal colonisation parameters compared with the untreated control. Dazomet displayed the greatest inhibitory effects on AMF establishment. In addition, the intensity and number of bands corresponding to Glomus spp. obtained with temporal temperature-gradient gel electrophoresis were lower for strawberry plants from biofumigant treatments than from the control. For the inoculated plants, there were almost no significant differences among the mycorrhizal colonisation parameters. The mass of leaves for the uninoculated and inoculated plants was higher for almost all non-chemical soil fumigant treatments compared with the control, except for heating of the uninoculated treatments. The number of strawberry fruits for the uninoculated biofumigant treatments was the highest, being higher than the values observed for the heating treatments, the chemical disinfection treatments and the control. There were no significant differences among the inoculated treatments. Biofumigation with Brassicaceae species resulted in higher soil organic matter and mineral nutrients and had a relatively small effect on AMF colonisation (F% = 59.0, 80.3, 47.3 for Bj, Es and Sa, respectively) compared with uninoculated controls (F% = 84.3). Despite the reduced AMF colonisation, biofumigation resulted in a higher fruit number and mass of leaves. Therefore, it represents a non-chemical soil fumigation method that should be applied in sustainable strawberry production.     

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.     

Hull to caryopsis adhesion and grain skinning in malting barley: Identification of key growth stages in the adhesion process

Strong adhesion between the hull and the caryopsis is essential for barley to be of good malting quality. Poor hull adhesion, a condition known as grain skinning, is undesirable for malting and downstream processes. At present, the processes mediating hull adhesion during grain development are poorly understood. The barley cultivar Chariot was grown in greenhouse conditions and grain development was recorded at defined growth stages to examine the timing of hull adhesion. Initiation of adhesion was first observed when caryopsis fresh weight and volume were approaching their maximum at 19 days after anthesis, during early dough. Hull adhesion was complete by 27 days after anthesis, or soft dough. Sections of developing grains were observed using light and transmission electron microscopy to examine a lipid-rich cementing layer believed to be responsible for adhesion between the hull and the pericarp. Evidence for a lipid-rich cementing material was supported by the observation that neither pectinase nor cellulase effected hull loosening. Grain growth, the presence of globular material originating from the pericarp and an electron dense material in the cementing layer are discussed in relation to hull adhesion. Grain skinning could be caused by poor adherence of cuticular material or inadequate fusion between cuticles.     

Effects of particle size on the quality attributes of reconstituted whole-wheat flour and tortillas made from it

The objective of this study was to examine the effects of whole-wheat flour (WWF) particle size on the quality attributes of WWF tortillas. WWF samples of different particle size distributions from commercial U.S. hard white (median diameters: 175.7, 128.6, 120.0, 108.5 and 102.4 μm), hard red winter (median diameters: 173.7, 133.6, 124.3, 110.8 and 104.2 μm) and hard red spring (median diameters: 173.7, 132.1, 124.7, 112.9, 106.3 μm) wheat classes were obtained by fine grinding of bran and shorts and re-combining with the rest of fractions. For all three wheat classes, as WWF median particle size decreased, the L* (lightness) value decreased but the adjusted damaged starch, polyphenol oxidase activity, and a* and b* values increased. Mixolab data showed that development time decreased as WWF particle size was reduced, while stability time and starch retrogradation increased. As for WWF tortilla quality, the breaking force and extensibility increased with decreasing particle size from ∼175 to 129–134 μm, but diameter and thickness were not significantly affected. The results indicated that reducing the median particle sizes of WWFs from ∼175 μm to ∼130 μm would significantly improve the WWF tortilla quality.     

Oat protein solubility and emulsion properties improved by enzymatic deamidation

Oat protein produced by a dry milling process was enzymatically deamidated by a food-grade protein-glutaminase (PG), and the effects on structure, solubility and emulsifying properties of oat proteins were studied. The reactions were conducted at neutral pH and low salt concentration conditions. Oat proteins were deamidated up to a deamidation degree of 59%. The solubility of proteins doubled. Oil-in-water emulsions prepared with the native and deamidated oat proteins differed as the emulsions prepared from oat proteins with high deamidation degree had a more uniform oil droplet particle size and longer stability. Fourier transform infrared (FT-IR) analysis demonstrated that oat protein secondary structure became more flexible by deamidation. Protein-glutaminase mediated deamidation appeared to be a promising technique to improve oat protein functionality such as emulsifying ability and solubility.     

Whole wheat bread: Effect of bran fractions on dough and end-product quality

Consumption of whole-wheat based products is encouraged due to their important nutritional elements that benefit human health. However, the use of whole-wheat flour is limited because of the poor processing and end-product quality. Bran was postulated as the major problem in whole wheat breadmaking. In this study, four major bran components including lipids, extractable phenolics (EP), hydrolysable phenolics (HP), and fiber were evaluated for their specific functionality in flour, dough and bread baking. The experiment was done by reconstitution approach using the 2⁴ factorial experimental layout. Fiber was identified as a main component to have highly significant (P < 0.05) and negative influence on most breadmaking characteristics. Although HP had positive effect on farinograph stability, it was identified as another main factor that negatively impacted the oven spring and bread loaf volume. Bran oil and EP seemed to be detrimental to most breadmaking characteristics. Overall, statistical analysis indicates that influence of the four bran components are highly complex. The bran components demonstrate multi-way interactions in regards to their influence on dough and bread-making characteristics. Particularly, Fiber appeared to have a high degree of interaction with other bran components and notably influenced the functionality of those components in whole wheat bread-making.     

Effect of Pichia membranaefaciens on ROS metabolism and postharvest disease control in citrus fruit

The yeast Pichia membranaefaciens has antagonistic effects against a wide range of phytopathogenic fungi that cause postharvest fruit decay. This work evaluated the effects of P. membranaefaciens on the reactive oxygen species (ROS) metabolism and disease control in harvested citrus fruit (Citrus sinensis L. Osbeck). The lesion diameter caused by Penicillium italicum and Penicillium digitatum on citrus fruit was remarkably reduced when the fruit was point-inoculated or dipped in a suspension of P. membranaefaciens at 1 × 10⁸ CFU mL⁻¹. The application of P. membranaefaciens on citrus fruit enhanced the activity of superoxide dismutase, ascorbate peroxidase, and glutathione reductase, as well as the levels of hydrogen peroxide, the superoxide anion and glutathione, but inhibited the decreasing ascorbic acid content. Furthermore, catalase activity was decreased by the same treatment. These results indicated that yeast treatment induced the synthesis of antioxidant enzymes which might have antagonistic effects against postharvest green and blue mold infection in citrus fruit.     

Effect of physicochemical and empirical rheological wheat flour properties on quality parameters of bread made from pre-fermented frozen dough

The objective of this study was to examine the influence of flour quality on the properties of bread made from pre-fermented frozen dough. The physicochemical parameters of 8 different wheat flours were determined, especially the protein quality was analysed in detail by a RP-HPLC procedure. A standardized baking experiment was performed with frozen storage periods from 1 to 168 days. Baked bread was characterised for specific loaf volume, crumb firmness and crumb elasticity. The results were compared to none frozen control breads. Duration of frozen storage significantly affected specific loaf volume and crumb firmness. The reduction of specific loaf volume was different among the used flours and its behaviour and intensity was highly influenced by flour properties. For control breads wet gluten, flourgraph E7 maximum resistance and RVA peak viscosity were positively correlated with specific loaf volume. However, after 1–28 days of frozen storage, wet gluten content was not significantly influencing specific loaf volume, while other parameters were still significantly correlated with the final bread properties. After 168 days of frozen storage all breads showed low volume and high crumb firmness, thus no significant correlations between flour properties and bread quality were found. Findings suggest that flours with strong gluten networks, which show high resistance to extension, are most suitable for frozen dough production. Furthermore, starch pasting characteristics were also affecting bread quality in pre-fermented frozen dough.     

Metabolite profiling of the response to high-nitrogen fertilizer during grain development of bread wheat (Triticum aestivum L.)

Wheat yield and quality are dependent largely on nitrogen (N) availability. In this study, we performed the first metabolomic analysis of the response to high-N fertilizer during wheat grain development using non-targeted gas chromatography-mass spectrometry (GC–MS). Quality parameter analyses demonstrated that high-N fertilizer application led to a significant increase in grain protein content and improvement in starch and bread-making quality. Comparative metabolomic profiling of six grain developmental stages resulted in identification of 74 metabolites, including amino acids, carbohydrates, organic acids and lipids/alcohol, which are primarily involved in carbon and N metabolism. Under high-N fertilizer treatment, numerous metabolites accumulated significantly during grain development. Principal component analysis revealed two principal components as being responsible for the variances resulting from N-fertilizer treatments. Metabolite–metabolite correlation analysis demonstrated that the high-N treatment group had a greater number of positive correlations among metabolites, suggesting that high-N fertilizer treatment induced a concerted metabolic change that resulted in improved grain development. Particularly, the high-N treatment-mediated significant accumulation of metabolites involved in the TCA cycle, starch and storage protein synthesis could be responsible for the improvement of grain yield and quality. Our results provide new insight into the molecular mechanisms of wheat grain development and yield and quality.     

Responses of glutamine synthetase activity and gene expression to nitrogen levels in winter wheat cultivars with different grain protein content

Glutamine synthetase (GS) plays a central role in plant nitrogen (N) metabolism, which improves crops grain protein content. A pot experiment in field condition was carried out to evaluate GS expression and activity, and grain protein content in high (Wanmai16) and low grain protein (Loumai24) wheat cultivars under two N levels (0.05 and 0.15 g N kg⁻¹ soil). High nitrogen (HN) resulted in significant increases in GS1 and GS2 expression at 10 days after anthesis (DAA), and higher GS activity during the entire grain filling stage. HN also significantly increased yield, grain protein content and protein fraction (except for glutenin of Luomai24) in two wheat cultivars, which indicated that it increased grain yield and protein content by improving nitrogen metabolism. Wanmai16 showed higher grain protein content, gliadin and glutenin content, and had higher expression level of GS2 both in flag leaves and grains at early grain filling stage. However, Luomai24 had greater yield and higher expression level of GS1. The difference expression of GS2 and GS1 genes indicates they had various contributions to the accumulation of protein and starch in wheat grains, respectively. The results suggest that GS2 would be serving as a potential breeding target for improving wheat quality.     

Polymerisation of gluten proteins in developing wheat grain as affected by desiccation

The breadmaking quality of wheat is affected by the composition of gluten proteins and the polymerisation of subunits that are synthesised and accumulated in developing wheat grain. The biological mechanisms and time course of these events during grain development are documented, but not widely confirmed. Therefore, the aim of this study was to monitor the accumulation of gluten protein subunits and the size distribution of protein aggregates during grain development. The effect of desiccation on the polymerisation of gluten proteins and the functional properties of gluten were also studied. The results showed that the size of glutenin polymers remained consistently low until yellow ripeness (YR), while it increased during grain desiccation after YR. Hence, this polymerisation process was presumed to be initiated by desiccation. A similar polymerisation event was also observed when premature grains were dried artificially. The composition of gluten proteins, the ratios of glutenin to gliadin and high molecular weight-glutenin subunits to low molecular weight-glutenin subunits, in premature grain after artificial desiccation showed close association with the size of glutenin polymers in artificially dried grain. Functional properties of gluten in these samples were also associated with polymer size after artificial desiccation.     

Phenolic compounds,antioxidant capacity and gelling properties of glucoarabinoxylans from three types of sorghum brans

Arabinose to xylose ratio (A/X), phenolics, antioxidant capacity and gelling properties were evaluated in glucoarabinoxylans (GAX) extracted from white (W-GAX), red (R-GAX) and high tannin (T-GAX) sorghum brans (SB). The characterization of arabinoxylans from corn fiber (CFAX) was used as benchmark. Sorghum GAX had higher branched structure (A/X 1.08–1.41) than CFAX (0.59). Nine 3-deoxyanthocyanins (3-DAs) were identified in SB and two glycosylated forms remained associated to the R-GAX and T-GAX extracts. T-GAX was the only that contained tannins (0.41 mg catechin equivalents (CE)/g dry basis (db)) and exerted the highest antioxidant capacity (81.75 mM Trolox equivalents (TE)/g db) followed by R-GAX (48.49 mM TE/g db), which contained the highest amount of 3-DAs (0.11 mg Luteolinidin equivalents (Lut eq)/g db), and W-GAX (35.45 mM TE/g db) that was not significantly different from the CFAX (25.83 mM TE/g db). Among sorghums, only the W-GAX gelled but it formed a weaker gel compared to CFAX likely due to its lower hydroxycinnamic acids (HCA) concentration. The presence of 3-DAs in the structure of R-GAX and T-GAX affected negatively their solubility and gelling properties. The different SB showed potential as sources of GAX with antioxidant capacity.     

Structure,chemical composition and enzymatic activities of pearlings and bran obtained from pearled wheat (Triticum aestivum L.) by roller milling

While abrasive pearling (also referred to as debranning) of wheat kernels prior to milling increases the quality of the resultant flour for producing bread, the potential applications of the co-products of pearling is largely unknown. We studied the impact of different degrees of pearling (0, 3, 6, 9 and 12% by weight) on the composition of pearlings and bran obtained when subsequently roller milling pearled wheat kernels. Pearling does not remove the kernel outer tissues homogeneously as abrasion affects especially the accessible parts of the kernels. Nevertheless, the first 3% removed consisted of mainly pericarp. With 6% or more removed, a significant amount of starchy endosperm ended up in the pearlings. The starting bran material and bran obtained by subsequent roller milling of pearled wheat kernels had similar compositions but the latter had a lower average particle size. Moreover, removal of the outermost kernel layers substantially decreased the enzyme activity levels in the bran.