Contributions of individual and combined Glu-B1x and Glu-B1y high-molecular-weight glutenin subunits to semolina functionality and pasta quality

Durum wheat is an important food crop used primarily for pasta production. High-molecular-weight glutenin subunits (HMW-GS) encoded by the closely linked genes Glu-B1x and Glu-B1y are known for their combined effects on pasta quality, but their individual contributions and interactions remain poorly understood. In this study, we show that individual loss-of-function mutants of Glu-B1x (ΔBx6) and Glu-B1y (ΔBy8) were associated with significant reductions in gluten strength compared to the wildtype, with stronger effects in the ΔBxy double mutant. Reductions in gluten strength were reflected in reduced mixograph and alveograph parameters, gluten index, faster extrusion flow rates and increased cooking loss. Interestingly, the Glu-B1x mutation was also associated with significant increases in grain and semolina protein content, increased pasta firmness, reduced starch viscosity and increased amylose in ΔBx6 and ΔBxy. In general, the ΔBx6 mutation had stronger effects than the ΔBy8 mutation, and significant interactions between the two genes were frequent. In addition to the basic knowledge gained on the individual effects of the Bx6 and By8 subunits and their interactions, the genetic stocks developed in this study provide useful tools to study the effects of natural or synthetic HMW-GS on pasta quality parameters in a background lacking endogenous HMW-GS.     

GlutoPeak parameters of whole wheat flours for gluten quality evaluation in soft wheat breeding programs

In soft wheat breeding programs, the gluten strength of flours from specific genotypes is determined by various chemical and rheological tests. Based on such tests, the experimental wheat lines with very weak flour gluten are typically selected for the production of soft-dough biscuits, while the lines with medium gluten strength and extensibility are reserved for hard-dough biscuits. Often, the genotypes having high gluten strength are removed from such breeding programs. In the present study, the usability of the GlutoPeak tester on whole wheat flour samples was investigated for assessing the gluten strength of soft wheat breeding materials. In the study, 25 soft wheat genotypes, grown in seven locations for three years, were categorized by commonly used gluten-quality-related parameters. Based on the results of the study GlutoPeak whole wheat flour PMT values ranging from 30.0 to 50.0 s and AM values from 15.0 to 20.0 GPU were found to be suitable for soft-dough biscuit products, whereas the values between 40.0 and 60.0 s and 20.0 and 23.0 GPU were appropriate for hard-dough biscuit products. The genotypes exhibiting AM values > 24.0 GPU and PMT values > 60.0 s were judged to have too-strong gluten, and thus eliminated from the breeding program. The gluten aggregation energy (AGGEN), and the torque after the maximum torque (PM) values were only useful and applicable to flours for soft-dough products. The maximum torque (BEM) values were not effective in discriminating against the genotypes. The results of this study demonstrated that the GlutoPeak whole wheat PMT and AM parameters can be recommended as quick and accurate parameters especially for early generation screening with small-scale tests in soft wheat improvement programs.     

Soluble arabinoxylans extracted from soft and hard wheat show a differential prebiotic effect in vitro and in vivo

Arabinoxylans (AX) are part of dietary fiber. They are currently under study due to their potential prebiotic effect. Wheat whole grain flours contain all the grain layers and, therefore, present a higher arabinoxylan content than white flour. It is known that the chemical structure of these compounds varies with the type of wheat cultivar and the tissue from which they are extracted. In this work, water soluble extractable arabinoxylans (WE-AX) from two types of wheat whole flours (hard and soft) were extracted. We characterized the molecular size distribution and the potential prebiotic effect of those extracts. The prebiotic effect was evaluated in vitro and confirmed in vivo. Bacterial group abundance (Lactobacillus, Bifidobacterium, Clostridium, Enterococcus, Bacteriodes and total bacteria) was determined by quantitative RT-PCR. The molecular size of AX from hard wheats was significantly higher than AX from soft wheats. Both extracts showed potential prebiotic activity by increasing the growth of beneficial bacteria in vitro and in vivo, decreasing the pathogens in the profile of intestinal microorganisms and increasing the amount of short chain fatty acids in the intestine. WE-AX from hard wheat showed a higher prebiotic activity. Prebiotic effect assessed in vitro and in vivo assays showed a significant correlation between both types of analysis. This finding suggests that the in vitro indices performed allow predicting the potential prebiotic effect in vivo.     

Spatial distribution of functional components in the starchy endosperm of wheat grains

The starchy endosperm of the mature wheat grain comprises three major cell types, namely sub-aleurone cells, prismatic cells and central cells, which differ in their contents of functional components: gluten proteins, starch, cell wall polysaccharides (dietary fibre) and lipids. Gradients are established during grain development but may be modified during grain maturation and are affected by plant nutrition, particularly nitrogen application, and environmental factors. Although the molecular controls of their formation are unknown, the high content of protein and low content of starch of sub-aleurone cells, compared to the other starchy endosperm cells types, may result from differences in developmental programming related to the cells having a separate origin (from anticlinal division of the aleurone cells). The gradients within the grain may be reflected in differences in the compositions of mill streams, particularly those streams enriched in the central and outer cells of the starchy endosperm, respectively, allowing the production of specialist flours for specific end uses.     

Characterization and comparison of predominant aroma compounds in microwave-treated wheat germ and evaluation of microwave radiation on stability

The present study was performed to evaluate the effects of microwave (MW) output power and treatment time on moisture content, lipase and lipoxygenase activities as well as colour changes of wheat germ (WG). In addition, the key aroma compounds in different MW-power-treated WG, which is of importance to the flavour of WG products, were also investigated. The obtained results showed that MW treatment maintained the inherent colour of WG and significantly reduced the moisture content (maximum reduction of 95%) and the activities of lipase and lipoxygenase (maximum reduction of 65% and 99%, respectively). In terms of aroma compounds, with the increase of the MW output power, the content of esters, alkanes, alcohols and acids decreased, while the content of heterocyclic compounds, nitrogen-containing compounds, aldehydes and ketones increased, providing more compounds with roasted flavour and less volatiles with grass-like flavour. Therefore, MW treatment was an effective stabilization method for WG utilization.     

Genetic responses in milling,flour quality,and wheat sensitivity traits to grain yield improvement in U.S. hard winter wheat

A rising global population necessitates continued genetic improvement of wheat (Triticum spp.), but not without monitoring of unintended consequences to processors and consumers. Our objectives were to re-establish trends of genetic progress in agronomic and milling traits using a generational meter stick as the timeline rather than cultivar release date, and to measure correlated responses in flour quality and human wheat-sensitivity indicators. Grain yield and kernel size showed stepwise increases over cycles, whereas wheat protein content decreased by 1.1 g/100 g. Reduced protein content, however, did not result in lower dough strength pertinent to bread baking. A novel method of directly testing gluten elasticity via the compression-recovery test indicated a general increase in gluten strength, whereas the ratio of total polymeric to total monomeric proteins remained stable. Also showing no change with genetic progress in yield were flour levels of gluten epitopes within the key immunotoxic 33-mer peptide. The oligosaccharide fructan, present in milled and wholemeal flours, increased with increasing grain yield potential. While yield improvement in U.S. bread wheat was not accompanied by a decline in gluten strength or systematic shift in a key wheat sensitivity parameter, the unanticipated rise in total fructans does implicate potentially new dietary concerns.     

Effects of wheat tempering and stone rotational speed on particle size,dough rheology and bread characteristics for a stone-milled weak flour

The poor technological performance of weak wheat flours means that they are usually considered difficult to be transformed into satisfactory bread. During milling, there are several settings that can affect flour characteristics. In this study, we tested two operative parameters that have the potential to affect flour quality – stone rotational speed and wheat tempering. Tempering moistures were set at 11%, 13%, 15%, and 17%, while stone rotational speeds were set at 173, 260, and 346 rpm. Both factors were found to affect operative milling parameters, notably flour yield, process productivity and specific energy consumption. Grain moisture had a significant effect on both dough rheology and bread characteristics (dough stability, tenacity, and extensibility). Dough stability was maximum at 13% moisture. Dough tenacity decreased as moisture increased, while extensibility increased as moisture increased. Bread specific volume and crumb specific volume were improved at 13% and 15% moisture. In conclusion, wheat tempering can be used to improve the potential of a weak flour and bread characteristics, while stone rotational speed affects operative parameters and white flour yield.     

Impact of ethanol,succinic acid,and the combination thereof at levels produced during sponge fermentation on hard wheat,soft wheat,and durum wheat farinograph rheology

The sponge and dough mixing process is one of the most common in the world, yet the mechanistic understanding of this process has yet to be sufficiently explored. In this study, aqueous solutions of ethanol, succinic acid, and their combination were prepared at concentrations intended to replicate fermentation times of 3, 4 and 6 h. These solutions were added to a farinograph mixer to make dough using hard wheat, soft wheat, and durum wheat flour. The results indicate that these yeast metabolites (ethanol, succinic acid) impact the mixing resistance, peak mixing value, and dough mixing stability in each of the flour types, likely primarily affected by the ratios of gliadin to glutenin and LMW glutenin in each flour type. Results suggest a stabilizing non-covalent interaction imparted by gliadin at peak mixing time, a stabilizing effect of HMW glutenin during break down, and synergistic effects of ethanol and succinic acid that leads to a faster rate of breakdown in later stages of mixing. It also suggests an increase in mixing resistance when acidulants are added to durum wheat dough. Taken together, this study adds new insights on the sponge and dough mixing process in a way that has not previously been conducted.     

Variability and cluster analysis of arabinoxylan content and its molecular profile in crossed wheat lines

Non-starch polysaccharides (NSP) in cereals, after starch and gluten proteins, determine the technological and nutritional properties of flour, dough and end product. From NSPs, the arabinoxylans are the most important components studied in wheat nowadays. The novelty of our study is the investigation of the variability and clustering ability of the wheat lines based on different quantitative and qualitative traits of arabinoxylans. The quantitative properties, the total and the water-extractable arabinoxylan content of wheat flours were measured separately by gas chromatography. The qualitative property referring to the structure of the molecule was the molecular weight distribution measured by size exclusion liquid chromatography. According to the results the variability of arabinoxylan properties in the breeding lines varied between wider ranges then the values measured for the parental varieties. The correlation between the quantitative parameters, and a trend between quantitative and qualitative parameters were described. During the cluster analysis, the parents were well separated into different groups. The parameters that played an important role in the clustering were the ratio of the probability of occurrence of molecular size ranges along with the quantitative traits of AX. The selected samples can be used for further targeted breeding while the methodology was used in this work can be suitable for selecting lines/varieties for special food or other industrial applications.     

Gluten proteome comparison among durum wheat genotypes with different release date

In order to deepen insight into durum wheat prolamin composition in relation to both end use quality and gluten related disorders, a phenotyping of four genotypes of different release date and technological performance was carried out. A proteomic approach integrated with the evaluation of protein aggregation level, amino acid composition and reactivity to G12 monoclonal antibody, was adopted. The degree of polymerization, estimated as unextractable polymeric proteins (UPP), was positively influenced by Cys-rich proteins (Glu-B3 LMW-GS), with Saragolla showing up to 40% higher values than other genotypes. The proteomic assessment allowed to identify proteins involved in gluten related disorders. In particular, ω5-gliadin involved in wheat allergy (WA), resulted markedly over-expressed in the old landrace Dauno III, up to four-fold than in modern Saragolla. A marked influence of genotype on the expression level of gliadins containing toxic epitopes (TECP) was observed with the more recent genotypes showing lower values (−53%). Also, reactivity to G12 moAb resulted higher in the two old genotypes consistently to their higher celiac disease (CD) toxicity evaluated by the proteomic approach. In conclusion a better gluten composition for processing seems to be associated to a lower expression level of CD toxic peptides and Tri a 19.     

Pilot scale production of a non-immunogenic soluble gluten by wheat flour transamidation with applications in food processing for celiac-susceptible people

Celiac disease (CD) is an immune-mediated disease triggered by wheat gluten and related prolamins. A lifelong gluten-free (GF) diet is mandatory to normalize the intestinal mucosa. We previously found that transamidation by microbial transglutaminase of gluten was effective in suppressing the gliadin-specific inflammatory response in CD patients without influencing the main technological properties of wheat flour or semolina. In this study, we produced on a pilot scale a soluble form of transamidated gluten (soluble protein fraction, spf), characterised by a high protein content (88 mg/ml), while native gluten was dramatically reduced (32 ± 2 ppm; R5-ELISA). Using HLA-DQ8 transgenic mice as a CD model, we found suppression of interferon-γ secretion in gliadin-specific CD4⁺ T cells challenged with spf-primed dendritic cells. In terms of functional properties, spf showed both solubility and emulsifying activity values within the range of commercial soluble glutens. Notably, dough prepared by mixing rice flour with spf could leaven. After baking, blended rice bread had a higher specific volume (2.9 ± 0.1) than control rice bread (2.0 ± 0.1) and acquired wheat-like sensory features. Taken together, our results highlighted the technological value of transamidated soluble gluten to improve both nutritional and sensory parameters of GF food.     

Genotypic variations in zinc accumulation and bioaccessibility among wheat (Triticum aestivum L.) genotypes under two different field conditions

Zinc (Zn) is an essential micronutrient for human health. Breeding zinc-rich crop genotypes is considered as potential solution to Zn deficiency. In this study, variation of Zn uptake, accumulation, distribution and the estimated bioaccessibility among 30 wheat genotypes across two locations were investigated with field experiments. A significant difference in grain Zn concentrations occurred across the two locations, with the corresponding values of 55.24 and 57.14 mg kg⁻¹. Grain Zn concentration was significantly and positively correlated with grain Mn concentration (0.698**, 0.617** for two locations). The estimated grain Zn bioaccessibility also showed a significant difference, a trend similar to grain Zn concentrations but with lower values (13.87 and 13.49 mg Zn d⁻¹ for two locations). These results indicate that the interaction of locations * genotypes may play an important role in grain Zn concentrations and Zn bioaccessibility.     

Benzoxazinoid and alkylresorcinol content,and their antioxidant potential,in a grain of spring and winter wheat cultivated under different production systems

The health-promoting properties of the grains of common wheat (Triticum aestivum L.) are associated with the presence of unique phytochemicals. This study determines the profile of alkylresorcinols (ARs) and benzoxazinoids (BXs) in T. aestivum spring and winter cultivars grown in Poland under the two different production systems: conventional and organic. Wheat grain extracts were subjected to qualitative and quantitative UPLC-UV-MS/MS analyses. The ARs profile consisted of five 5-n-alkylresorcinol derivatives, among which 5-n-heneicosylresorcinol (C21:0) and 5-n-nonadecanylresorcinol (C19:0) predominated; while six different BXs were determined in hydrothermally treated grains. Our research shows significant differences in the contents of ARs and BXs among wheat cultivars, as well as the two production systems used. Organically grown varieties had their total contents of ARs and BXs significantly higher than those grown conventionally. Another aim of the study was to determine the antioxidant capacity of alkylresorcinol extracts from tested wheat cultivars. The quantitative TLC-DPPH• method for determining the antiradical capacity of wheat ARs extracts was developed. We observed a positive relationship between the free radical scavenging activity of extracts and the total amount of ARs. The biological activity research is important for developing value-added wheat cultivars, having an improved profile and composition of nutritional substances.     

Application of an orcinol-ferric chloride colorimetric assay in barley and wheat accessions for water-extractable and total arabinoxylan

Arabinoxylan is an important hemicellulose potentially affecting wheat baking qualities, barley malt quality, and may impart prebiotic benefits. Water-extractable (WEAX) and total arabinoxylan (TOAX) were characterized in 204 wheat and barley accessions, respectively, using an orcinol-ferric chloride assay. WEAX measurement accuracy was optimum when glucose concentration was greater than 12–13 times pentose concentration. The modified method removed enough excess glucose spectral absorbance to make the corrected and uncorrected lines different, but still significantly correlated (p = 0.009, R = 0.94). Mean WEAX (expressed as percentage WEAX of TOAX) for the wheat accessions was 15.90%, ranging from 8.82% to 24.87%, and for barley accessions WEAX the mean was 7.10%, and ranged from 2.98% to 13.86%. Conclusions are 1) the assay is useful for a breeding program because of its semi-high throughput design for the simultaneous analysis of 16 (WEAX) to 40 (TOAX) barley lines or 24 (WEAX) to 40 (TOAX) wheat lines, 2) the trichromatic measurement reduces the impact of glucose, and 3) the broad range of WEAX measured showed that barley and wheat accessions vary in their extractable and unextractable components.     

Mass spectrometry imaging of BARLEYmax fructooligosaccharides

BARLEYmax is a novel hull-less barley cultivar lacking activity of a key enzyme required for starch synthesis (SSIIa), resulting in a grain with reduced total starch, higher dietary fiber, and higher fructan content. In this study, we examined the quantitative differences in fructan among 2 hull-less barley lines (BARLEYmax and Mannenboshi) and 2 peeled barley lines (Glutinous barley rice and Hindmarsh). We found that BARLEYmax had a higher fructan content, particularly 2 types of fructooligosaccharides (FOS), namely kestose and nystose, the important components of fructan that have some beneficial effects for human health. We established a mass spectrometry imaging (MSI) method to further investigate the content and localization of FOS in the barley lines. We found that kestose, nystose, and fructosyl-nystose showed increased molecular ion intensities in BARLEYmax compared with those in other barley lines. These results confirmed that the loss of SSIIa activity in BARLEYmax leads to a decrease in starch in the cytoplasm and an increase in fructan in the vacuole as an energy store. Overall, these findings demonstrate that MSI analysis is helpful for understanding FOS localization in cereal grains and for visual comparison among matured grains.     

New angiotensin-converting enzyme inhibitory peptide from Coix prolamin and its influence on the gene expression of renin-angiotensin system in vein endothelial cells

Coix seed, which is a traditional Chinese medicine, has been used to treat hypertension for thousands of years. It has been shown that Coix prolamin peptides display high levels of angiotensin I converting enzyme (ACE) inhibitory activity. Hence, we purified the ACE inhibitory peptides from Coix prolamin hydrolysates and evaluated the influence of the most potent peptide on the renin-angiotensin system (RAS) genes expression in human umbilical vein endothelial cells (HUVECs). In this study, Coix prolamin peptides were sequentially separated by ultrafiltration, ion exchange chromatography, gel filtration chromatography and RP-HPLC, while the peptide structure was analyzed by mass spectrometry. Next, in silico proteolysis, pharmacophore and molecular docking were further applied to screen and optimize the structure of peptides. Finally, a novel ACE inhibitory peptide VDMF was obtained, in which its influence on the gene expression of RAS signaling pathway in AngⅡ-injury HUVECs was evaluated by quantitative real-time PCR. VDMF significantly down-regulated ACE, AngII type 1 receptor (AT1R) and ACE2 mRNA expression in comparation with model group, while up-regulating Mas gene expression. Hence, we obtained a novel antihypertensive candidate that was derived from the Coix peptides, which could involve a multi-modulation mechanism that regulates blood pressure.     

Breeding and biotechnological efforts in Jatropha curcas L. for sustainable yields

Jatropha is a non-edible, important bioenergy plant, which can grow in marginalized land. The seeds possess about 36% oil and this would be converted into biodiesel or biojet-fuel. Jatropha provides an option for sustainable feed and fuel production due to its inherent qualities including hardy nature, drought tolerance and surviving with limited amount of water, tolerance to unfavorable conditions and excessive moisture. However, heterozygosity, low productivity and poor understanding of its genome are the major impediments to elite line development. Further, classical breeding and advanced technological investments remain limited owing to long juvenile phase and breeding cycles. Scientific technologies that lead to identification of elite genotypes and development of high yielding elite Jatropha lines and effective methods of detoxification of seeds needs immediate priority. Efficient tissue culture system, doubled haploids (DH) and genomic tools are increasingly made available to improve the seed yield and its oil quantity through the development of geminivirus disease resistant lines. The application of advanced, sequencing technologies has presented a repertoire of genomic information for this important yet orphan crop. In the present investigation, we highlight the achievements made in Jatropha towards development of high yielding, virus resistant elite lines and hybrids with yield potential ranging from 3 to 5 tons per hectare in a year, which is a first ever report in the world. We also developed potential biotechnological tools such as genetic transformation, genome editing and next generation genomics tools including linkage maps and QTLs for accelerating breeding efforts through marker assisted selection. Because of our concerted and continuous efforts during the past 15 years, we have overcome all the obstacles and developed high yielding, disease resistant hybrids/lines, advanced cultivation technologies with thorough knowledge on Agronomy of the Jatropha crop. The Jatropha cultivation technology developed for the first time in the world, could open up new avenues for higher yield productivity of commercial viability.     

Camelina sativa,a short gestation oilseed crop with biofuel potential: Opportunities for Indian scenario

Camelina is an oilseed crop which is being commercially produced globally as feedstock for biodiesel. Being a non-edible oil bearing low input crop owing to its low fertilizer and water requirement, fits well for biofuel production. In India, targets for biofuel blending has been set by New Biofuel Policy-2018 and to meet these targets efforts are being made to harness the potential of available feedstock in the country. Among these feedstock, contribution of short gestation oilseed bearing crop has been very important. Camelina has been introduced in India during 2009–10 as experimental crop by DIBER, DRDO. Since then various efforts have made to standardize the production technology of this crop under various agro-climatic regions of the country, crop improvement, oil quality analysis and development of high energy by-products. Camelina has various advantages to offer for Indian biofuel sector. This paper reviews the potential of this crop for Indian Biofuel scenario.