Genetic Diversity of Recurrent Selection Populations with Ms2 Gene Assessed by Gliadins in Common Wheat (Triticum aestivum L.)

The male-sterile lines with Ms2 gene were highly evaluated in recurrent selection in wheat （Triticum aestivum L.）. Three populations C6 （population after six cycles of selection）, C7 （population after seven cycles of selection）, and C8 （population after eight cycles of selection） were constructed through recurrent selection with 12 parental materials （P）. Acid polyacrymide gel electrophoresis （A-PAGE） analysis was used to identify gliadin patterns and evaluate the genetic diversity in 12 parents and three populations. A total of 63 bands were identified, of which 17 polymorphic bands and 7 unique bands were present in populations and seven polymorphic bands and four unique bands were present in parents. The number of polymorphic and unique bands decreased gradually from C6 to C8, especially for to- and y-gliadins. The genetic distances in C6, C7, and C8 were calculated. The distributions of genetic distance were different in three recurrent selection populations. From C6 to C8, the genetic distance was 0.2687, 0.2652 and 0.1987, respectively. Statistically significant differences were detected between C7 and C8 with the T value of 37.9718. The result of cluster analysis based on genetic similarity matrix of three populations fitted well to those of principle coordinates analysis （PCoA）. Compared with 12 parents, almost all individuals of three populations are new genotypes. Most of the individuals from C6 and C7 could be divided into two groups, while most individuals of C8 were in one cluster. In conclusion, the results indicated that the genetic diversity was decreased severely according to the information revealed by A-PAGE, although some variations could be created in the recurrent selection. It was necessary to introduce diverse germplasm based on the genetic database of recurrent population to maintain and improve the breeding efficiency in the further program.

New transcriptomic insights in two RNAi wheat lines with the gliadins strongly down-regulated by two endosperm specific promoters

The gluten proteins of wheat grain are responsible for visco-elastic properties of flour,but they also trigger the immune-response of celiac disease.In this work,two low-gliadin RNA interference(RNAi)wheat lines that differ for the promoter driving the silencing(D-hordein andγ-gliadin promoters for D783 and D793 lines,respectively),were characterized at transcriptomic,and protein fraction levels in the grain.Silencing of gliadins provides a readjustment in the grain protein fractions that also affects to the nongluten proteins(NGP),which were increased in both RNAi lines.Determination of wheat gluten by means of the R5 monoclonal antibody also showed a strong reduction in the content of gluten in both RNAi lines.Moreover,fructans,an oligosaccharide linked with the development of non-celiac wheat sensitivity(NCWS)were also significantly decreased in RNAi lines.The down-regulation of gliadins fractions also impacts to other metabolic processes,particularly on carbohydrate metabolism,enzyme regulator activity and response to stress.Genes and transcription factors regulated by ABA were up-regulated,which could suggest the implication of this phytohormone on the stress response observed in the RNAi lines.

Large enhancements in gelation behavior of wheat gliadins by incorporation of low concentrations of methylcellulose

Influence of non-gelling methylcellulose （MC） on gelation behavior of wheat gliadins in 13 wt% alkaline propanol/water （50：50, v/v） solution was investigated using dynamic theological time sweep test. Increasing MC concentration （CMC） up to CMC = 1 wt% caused a significant reduction in gelation time （tget） of the solution and an increase in loss tangent （tan δ） value of the resultant gel at T 〈 30 ℃.

RHEOLOGICAL PROPERTIES OF WHEAT GLIADINS IN AQUEOUS PROPANOL

Rheological properties of wheat gliadins in 50% （V/F） aqueous propanol were carried out as a function of gliadin concentration c and temperature. The solutions at 20 g L-1 to 200 g L-1 behave as Newtonian fluids with an flow activation energy of 23.5-27.3 kJ mol-1. Intrinsic viscosity [η] and Huggins constant kH are determined according to Huggins plot at c 〈 120 g L-1. The results reveal that gliadins are not spherical shaped and the molecular size tends to increase with temperature due to improved solvation.

Effect of high-nitrogen fertilizer on gliadin and glutenin subproteomes during kernel development in wheat(Triticum aestivum L.)

Nitrogen(N),a macronutrient essential for plant growth and development,is needed for biosynthesis of protein and starch,which affect grain yield and quality.Application of high-N fertilizer increases plant growth,grain yield,and flour quality.In this study,we performed the first comparative analysis of gliadin and glutenin subproteomes during kernel development in the elite Chinese wheat cultivar Zhongmai 175 under high-N conditions by reversed-phase ultra-performance liquid chromatography and twodimensional difference gel electrophoresis(2D-DIGE).Application of high-N fertilizer led to significant increases in gluten macropolymer content,total gliadin and glutenin content,and the accumulation of individual storage protein components.Of 126 differentially accumulated proteins(DAPs)induced by high-N conditions,24 gliadins,12 high-molecularweight glutenins,and 27 low-molecular-weight glutenins were significantly upregulated.DAPs during five kernel developmental stages displayed multiple patterns of accumulation.In particular,gliadins and glutenins showed respectively five and six accumulation patterns.The accumulation of storage proteins under high-N conditions may lead to improved dough properties and bread quality.

Null Alleles in Gliadin Coding Loci and Wheat Allergenic Properties

Wheat gliadin proteins-an important, nutritional component of many food products may also act as allergenic proteins causing various, clinical symptoms of IgE-mediated food allergies. Gliadins are coded by six complex loci on the chromosomes 1A, 1B, 1D,6A, 6B and 6D of wheat genome. Each of the loci coding from a few to a dozen of polypeptides may spontaneously mutate to inactive gene variants called null alleles that do not code any proteins at all. The aim of the present work was to find out whether null alleles in some gliadin coding loci may decrease wheat allergenic properties. Six winter wheat genotypes: gliadin deletion lines (GDL) containing null alleles on 1D, 1B and 6B chromosomes and control lines (CL) containing active gene variants in all gliadin coding loci, were developed using plant breeding methods. Allergenic properties of the six analyzed hybrids were estimated by ELISA using polled sera of five patients allergic to gluten. Estimated immunoreactivity of GDLs was from 6% to 18% lower as compared with CLs. The obtained results evidenced that gliadin null alleles decrease wheat allergenic properties and may be used as parental forms for breeding of hypoallergenic wheat genotypes.

Purified Wheat Gliadin Proteins as Immunoglobulin E Binding Factors in Wheat Mediated Allergies

Some wheat gliadin proteins are strong allergens that may cause various symptoms of food allergies and baker’s asthma. The most immunoreactive ω-5 gliadin fractions are the main allergens in wheat dependent exercise induced anaphylaxis (WDEIA). While the allergenicity of ω-5 is quite well understood, knowledge about α, β, γ and ω-1.2 gliadins is much more scanty. This study examines allergenic properties of other fractions as compared to ω-5. Gliadins were extracted from flour of winter wheat (Triticum aestivum L.) cultivar Ostka strzelecka. Purified samples representing proteins belonging to α, β, γ, ω-1.2 and ω-5 classes were isolated using preparative gel electrophoresis. Immuno-reactivity and allergenic properties of these proteins were analyzed by ELISA using sera from allergic patients with elevated sIgE (> 2KU/L), and by skin prick test (SPT). ELISA showed that ω-5 and ω-1.2 differed considerabely from α-, β- and γ-gliadins in respect of immunoreactivity. Responses of both ω-gliadins were almost twice as high as for other fractions. Significant differences were also observed among individual ω-gliadin fractions as evidenced by ANOVA. SPT showed that patient with symptoms of baker’s asthma and WDEIA had a positive results to all gliadins tested. Another patient with baker’s asthma (but not WDEIA) reacted positively only to ω-5 gliadins. In two patients with skin allergy SPT were negative with all analyzed proteins. Results show ω-1.2 gliadins to be almost as immunorective as ω-5. The α-, β- and γ-gliadins also recognize specific IgE antibodies, but their binding capacity is only about half that of ω-fractions. This kind of immunoreactivity could still be important since a cumulative effect of individual fractions may intensify disease symptoms in allergic patients.

Celiac disease serology in patients with different pretest probabilities: Is biopsy avoidable?

AIM: To establish the diagnostic performance of sev-eral serological tests, individually and in combination, for diagnosing celiac disease (CD) in patients with different pretest probabilities, and to explore potential se- rological algorithms to reduce the necessity for biopsy. METHODS: We prospectively performed duodenal biopsy and serology in 679 adults who had either high risk (n = 161) or low risk (n = 518) for CD. Blood samples were tested using six assays (enzyme-linked immunosorbent assay) that detected antibodies to tissue transglutaminase (tTG) and deamidated gliadin peptide (DGP). RESULTS: CD prevalence was 39.1% in the high-risk population and 3.3% in the low-risk group. In high-risk patients, all individual assays had a high diagnostic efficacy [area under receiving operator characteristic curves (AU ROC): 0.968 to 0.999]. In contrast, assays had a lower diagnostic efficacy (AU ROC: 0.835 to 0.972) in the low-risk group. Using assay combinations, it would be possible to reach or rule out diagnosis of CD without biopsy in 92% of cases in both pretest populations. We observed that the new DGP/tTG Screen assay resulted in a surplus compared to more conventional assays in any clinical situation. CONCLUSION: The DGP/tTG Screen assay could be considered as the best initial test for CD. Combinations of two tests, including a DGP/tTG Screen, might be able to diagnose CD accurately in different clinical scenarios making biopsy avoidable in a high proportion of subjects.

Construction of Gliadin Fingerprints Database for the Main Wheat Cultivars Grown in North China

The standard gliadin fingerprints and their database of 68 major cultivars and a part of backbone parents, which have ever been extensively grown in North China since the 1950' s, were constructed by using CAWGES software and an improved method of pH 3.2 A-PAGE. In the meantime, investigations were made on the utilization of the database in the area of gliadin fingerprints analysis, variety identification and genetic relationship study. The results showed that it provided an effective method for building core collections and variety identification.

Accumulation Pattern of Gliadin Fractions α, β, γ, ω and Regulation of Nitrogen

Gliadin, the major storage protein in endosperm, affects grain quality in spring wheat by its content and composition. Eighteen cultivars differing in HMW-GS were used in the study to approach the accumulation pattern of gliadin fractions α, β, γ, ω and regulation of three kinds of nitrogen source. The results showed that the content of gliadin in grains increased gradually along with the process of grain-filling, but the accumulation intensity and final content differed evidently among cultivars with different HMW-GS composition. Of all the subunit types used here, cultivars with subunits 7＋9 and 2＋12 had smaller accumulation intensity and lower final content. During grain-filling, 4 gliadin fractions had the same increase trend, but differed in accumulation course. The dynamic trends of gliadin accumulation were similar in different nitrogen treatments whose effects on initial amount, accumulation intensity and final level of accumulation varied with cultivars. Of three nitrogen fertilizer types, the amide-form nitrogen source was better to the formation and accumulation of gliadin as well as its four fractions.

Studies on Single Cell Culture in vitro in Wheat——The variation of grain protein content and its fractions from regenerated plants

On the basis of previous studies dealing with the variation of major agronomic and yield characteristics of regenerated plants derived from single cell culture in vitro of common wheat (Triticum aestivum L.Cultivar NE 7742), the grain protein content and its fractions from regenerated plants with stable agronomic characteristics were studied from 1992 to 1995. The results showed that the variation of grain protein content and its fractions in somaclones from single cell culture in vitro were very significant and the range was very wide (11531770%). Several types of variation were found in the studies, especially the type with higher protein content than that of cultivar NE 7742 (non-culture parent). Among them, -2069% of lines the grain protein content was significantly higher than that of NE 7742 and combined with high yielding potential. The tendency of variation of the four protein fractions showed that the variation of albumin was not obvious and maintained the same level as NE774 increased in some somaclones and decreased in others. However, the percentages both globulin and glutenin tended to increase. The variation of total amount of structural protein and the ratio between globulin and glutenin tended to increase. The variation of total amount of structural protein and the ratio between globulin and albumm was mainly influenced by globulin under the condition of culture in vitro. The variation of total amount of storage protein and the ratio between gliadin and glutenin was mainly affected by glutenin. The results mentioned above demonstrated that the induction and screening of somaclonal variation could be an effective way in wheat improvement in combining high protein content with high yield.

Diagnostic accuracy of a new point-of-care screening assay for celiac disease

AIM: To determine the diagnostic accuracy of a new point-of-care assay detecting anti-deamidated gliadin peptides in celiac disease(CD) patients.METHODS: One-hundred-and-twelve patients(age range: 1.8-79.2 years old) with clinical symptoms suggestive of CD and/or first-degree relatives(FDR) of CD patients(n = 66),and confirmed CD on a gluten-free diet(GFD)(n = 46),were prospectively enrolled in the study at Gastroenterology outpatient clinics for adult patients and from the Gastroenterology Consultation Ward at the Pediatric Department of the University Hospital of Geneva.Written informed consent was obtained from all subjects enrolled.The study received approval from the local ethics committee.The original CD diagnosis had been based on serum-positive IgA anti-tissue transglutaminase enzyme-linked immunosorbent assay(ELISA)(QuantaLite,Inova Diagnostics,San Diego,CA,United States) and on biopsy results.Serum samples from all study participants were tested by the new CD lateral flow immunochromatographic assay(CD-LFIA) device,Simtomax Blood Drop(Augurix SA,BioArk,Monthey,Switzerland) to detect immunoglobulin(Ig)A and IgG antibodies against deamidated gliadin peptides.The diagnostic performance was evaluated using receiver operating characteristic curves with 95%CIs.A cut-off of 2 on the Rann colorimetric scale was used to calculate the device's sensitivity and specificity.RESULTS: CD-LFIA was highly accurate in detecting untreated celiac patients.In the group of patients with CD symptoms and/or FDR,eight new cases of CD were detected by ELISA and biopsy.All of these new cases were also correctly identified by CD-LFIA.The test yielded four false positive and four false negative results.The false positive results were all within the groups with clinical symptoms suggestive of CD and/or FDR,whereas the false negative results were all within the GFD group.The test yeld a sensitivity of 78.9%(95%CI: 54.4-93.9) and specificity of 95.7%(95%CI: 89.4-98.8),and the area under the curve reached 0.893(95%CI: 0.798-0.988).The Kappa coefficient,calculated according to the values obtained by two readers from the same device,was of 0.96(SE: 0.06).When the GFD patients were excluded from the analysis,the area under the curve reached 0.989(95%CI: 0.971-1.000) and the Kappa coefficient,calculated according to the values obtained by two readers from the same device,became 0.96(SE: 0.07).Furthermore,using the Rann scale cut-off of 2 without the GFD patients,sensitivity was 100% and specificity was 93.1%(95%CI: 83.3-98.1).CONCLUSION: The new CD-LFIA rapid screening test shows good diagnostic accuracy,sensitivity and specificity,and may rule out CD in patients with CD-related symptoms.

Calcium glycerophosphate preserves transepithelialintegrity in the caco-2 model of intestinal transpo

AIM To assess the direct effects of ischemia onintestinal epithelial integrity. Furthermore, clinicalefforts at mitigating the effect of hypoperfusion on gutpermeability have focused on restoring gut vascularfunction.METHODS： we report that, in the Caco-2 cell modelof transepithelial transport, calcium glycerophosphate（CGP）, an inhibitor of intestinal alkaline phosphataseF3, has a significant effect to preserve transepithelialelectrical resistance （TEER） and to attenuate increasesin mannitol flux rates during hypoxia or cytokinestimulation.RESULTS： The effect was observable even at concentrationsas low as 1 μmol/L. As celiac disease is alsomarked by a loss of gut epithelial integrity, the effectof CGP to attenuate the effect of the α-gliadin peptide31-55 was also examined. In this instance, CGP exertedlittle effect of preservation of TEER, but significantlyattenuated peptide induced increase in mannitol flux.CONCLUSION： it appears that CGP treatment mightsynergize with other therapies to preserve gut epithelialintegrity.

A catalog of gliadin alleles:Polymorphism of 20th-century common wheat germplasm

A new, improved version of the catalog of 182 alleles at the six Gli loci of common wheat(T.aestivum L.) shown in electrophoregrams of 128 standard genotypes was used for analysis of1060 cultivars and lines bred in the 20 th century. The most frequent alleles in the studied germplasm occurred with frequencies of 18%–40%, with 30 unique alleles, one in each cultivar. Extremely high genetic diversity was found(average H for the six main Gli loci was0.870 ± 0.046), nearly identical in winter(H = 0.831) and spring(H = 0.856) wheats but differing among 28 groups of cultivars released in 22 countries. Each country or region was characterized by its own specific set of the most frequent Gli alleles, and the 28 cultivar groups formed five main relationship clusters if polymorphism at the six Gli loci was considered. However, different levels of similarity between groups of cultivars were found if polymorphism of the A, B, or D genomes of common wheat was tested separately. In general, the 20 th century germplasm of common wheat was differentiated and structured by country or region and cultivar type(spring or winter). Each elemental genome(in particular, A and D) contributed to the structure of the polymorphism studied. We propose that the structure of the wheat germplasm was a result of natural selection under the ecoclimatic conditions of cultivation specific to each country or region. As many as 27.4% of cultivars studied violated the requirement of the DUS rules for uniformity, being represented by mixtures of two or more closely related genotypes. However, the composition of a cultivar as a set of related but different genotypes may contribute to its adaptivity, and thereby to the known high plasticity of common wheat.

Non-invasive prediction of persistent villous atrophy in celiac disease

BACKGROUND Celiac disease(CD)is an immune-mediated enteropathy that is primarily treated with a gluten-free diet(GFD).Mucosal healing is the main target of the therapy.Currently,duodenal biopsy is the only way to evaluate mucosal healing,and noninvasive markers are challenging.Persistent elevation of anti-tissue transglutaminase antibodies(aTTG)is not an ideal predictor of persistent villous atrophy(VA).Data regarding prediction of atrophy using anti-deamidated gliadin peptide antibodies(aDGP)and abdominal ultrasonography are lacking.AIM To evaluate the ability of aTTG,aDGP,small bowel ultrasonography,and clinical and laboratory parameters in predicting persistent VA determined using histology.METHODS Patients with CD at least 1 year on a GFD and available follow-up duodenal biopsy,levels of aTTG and aDGP,and underwent small bowel ultrasonography were included in this retrospective cohort study.We evaluated the sensitivity,specificity,and positive and negative predictive values of aTTG,aDGP,small bowel ultrasonography,laboratory and clinical parameters to predict persistent VA.A receiver operating characteristic(ROC)curve analysis of antibody levels was used to calculate cut off values with the highest accuracy for atrophy prediction.RESULTS Complete data were available for 82 patients who were followed up over a period of four years(2014-2018).Among patients included in the analysis,women(67,81.7%)were predominant and the mean age at diagnosis was 33.8 years.Followup biopsy revealed persistent VA in 19 patients(23.2%).The sensitivity and specificity of aTTG using the manufacturer’s diagnostic cutoff value to predict atrophy was 50%and 85.7%,respectively,while the sensitivity and specificity of aDGP(using the diagnostic cutoff value)was 77.8%and 75%,respectively.Calculation of an optimal cutoff value using ROC analysis(13.4 U/mL for aTTG IgA and 22.6 U/mL for aDGP IgA)increased the accuracy and reached 72.2%[95%confidence interval(CI):46.5-90.3]sensitivity and 90%(95%CI:79.5-96.2)specificity for aDGP IgA and 66.7%(95%CI:41.0-86.7)sensitivity and 93.7%(95%CI:84.5-98.2)specificity for aTTG IgA.The sensitivity and specificity of small bowel ultrasonography was 64.7%and 73.5%,respectively.A combination of serology with ultrasound imaging to predict persistent atrophy increased the positive predictive value and specificity to 88.9%and 98%for aTTG IgA and to 90.0%and 97.8%for aDGP IgA.Laboratory and clinical parameters had poor predictive values.CONCLUSION The sensitivity,specificity,and negative predictive value of aTTG and aDGP for predicting persistent VA improved by calculating the best cutoff values.The combination of serology and experienced bowel ultrasound examination may achieve better accuracy for the detection of atrophy.

Cross-Reaction between Gliadin and Different Food and Tissue Antigens

A subgroup of coeliac disease patients continues to experience symptoms even on a gluten-free diet (GFD). We attempted to determine whether these symptoms could be due to either cross-contamination with gluten-containing foods or cross-reactivity between α-gliadin and non-gluten foods consumed on a GFD. We measured the reactivity of affinity-purified polyclonal and monoclonal α-gliadin 33-mer peptide antibodies against gliadin and additional food antigens commonly consumed by patients on a GFD using ELISA and dot-blot. We also examined the immune reactivity of these antibodies with various tissue antigens. We observed significant immune reactivity when these antibodies were applied to cow’s milk, milk chocolate, milk butyrophilin, whey protein, casein, yeast, oats, corn, millet, instant coffee and rice. To investigate whether there was cross-reactivity between α-gliadin antibody and different tissue antigens, we measured the degree to which this antibody bound to these antigens. The most significant binding occurred with asialoganglioside, hepatocyte, glutamic acid decarboxylase 65, adrenal 21-hydroxylase, and various neural antigens. The specificity of anti-α-gliadin binding to different food and tissue antigens was demonstrated by absorption and inhibition studies. We also observed significant cross-reactivity between α-gliadin 33-mer and various food antigens, but some of these reactions were associated with the contamination of non-gluten foods with traces of gluten. The consumption of cross-reactive foods as well as gluten-contaminated foods may be responsible for the continuing symptoms presented by a subgroup of patients with coeliac disease. The lack of response of some CD patients may also be due to antibody cross-reactivity with non-gliadin foods. These should then be treated as gluten-like peptides and should also be excluded from the diet when the GFD seems to fail.

Clinical utility of quantitative multi-antibody Polycheck immunoassays in the diagnosis of coeliac disease

AIM:To evaluate the clinical utility of multi-antibody strategies in the diagnosis of coeliac disease(CD),the new quantitative Polycheck immunoassays were analysed.METHODS:Polycheck Celiac Panels(PCPs)are immunoenzyme screening assays for the quantitative measurement of coeliac-specific immunoglobulin class G(Ig G)or class A(Ig A)in serum.Lines of relevant antigens are coated together with five Ig G or Ig A standard lines used for the standard curve as positive control.PCP IgA consists of human recombinant human tissue transglutaminase(t TG)and deamidated gliadin peptides(DGP)as targets to detect Ig A antibodies.PCP IgG consists of t TG,DGP and IF(intrinsic factor)antigens to detect antibodies in Ig G class.PCPs were performed on 50 CD patients,including 6 cases with selective Ig A deficiency,and 50 non-coeliac controls.CD diagnosis was performed according to the ESPGHAN recommendations:The presence of specific anti-t TG-Ig A or anti-DGP-Ig G(in the case of Ig A deficiency)antibodies,typical histopathological changes in duodenal mucosa described in Marsh-Oberhüber classification as at least grade 2.The diagnosis of the majority of the control subjects was functional gastrointestinal disorders.The PCP results were compared with reference EliA Celikey.RESULTS:The usage of PCPs led to the correct identification of all CD patients.In our study,PCPs showed 100%agreement with the histopathological results.PCP IgA test showed a 98%concordance and correlated positively(R=0.651,P=0.0014)with Eli A Celikey test.The highest specificity and positive predictive value(both 100%)were observed for the detection of Polycheck anti-t TG-Ig A antibodies.The highest sensitivity and negative predictive value(both 100%)were achieved by Polycheck anti-DGPIg G antibody detection.The best performance(98%sensitivity and negative predictive value,100%specificity and positive predictive value,diagnostic accuracy-AU ROC 99%)was observed for the strategy of using both PCP IgA and IgG and determining positive outcomes of the test with two or more coeliac-specific antibodies detected.The majority of coeliac patients had multiple antibodies.All four antibodies were detected in 7(14%)cases,19 children(38%)were positive for three antibodies and 23(46%)were positive for two antibodies.CONCLUSION:The present study showed that detection of coeliac-specific antibodies with multi-antibody PCPs is effective and efficacious in the diagnosis of CD.

Detection of Gluten in Dishes Offered as Gluten-Free in a Gastronomic Area Located in San José, Costa Rica

Celiac disease, gluten sensitivity and gluten intolerance are health conditions that require consumers to avoid their gluten intake. In Costa Rica, Law 8975 regulates the amount of gluten permitted in prepackaged products labeled as “gluten-free”, but the parameters to be followed are not mandated for food service operations. This study investigated whether restaurants with gluten-free (GF) options in a gastronomic area of the city of San José, Costa Rica, achieved the requirements of the legislation that the dishes offered should contain less than 20 ppm gluten. Using data collected from five restaurants offering GF dishes, two provided dishes with quantities of gluten greater than 20 ppm (restaurant A, four samples and restaurant B, three samples);particularly dishes from the category “meat with sauce”. Although those dishes are naturally gluten-free, when they are handled in areas of shared production, they are exposed to the risk of cross contact, furthermore the adding of misscellaneous such as: marinades, sauces and condiments, which could contain traces of gluten or hidden gluten, a risk associated with the use of ingredients without certification GF (supplier’s practices and label declaration). Therefore improvements in food service procedures should be enforced. The findings of the present study emphasize the need to include restaurant foods in the relevant legislation to ensure that the gluten-intolerant sector of the population remains safe when eating out.

Physicochemical and structural characteristics of the Venn components of wheat gliadin

The aim of this study was to analyze the physicochemical and structural characteristics of the Venn components of wheat gliadin to provide theoretical basis of gliadin for processing in dough and Chinese steamed bread. Eight Venn components, Gli-8, Gli-9, Gli-10, Gli-11, Gli-12, Gli-13, Gli-14, and Gli-15, were extracted from wheat gliadin based on their solubility. The results of physicochemical characteristics showed that the differences in the contents, TDS,electrical conductivity, particle size and zeta potential of Venn components were significant, respectively. The content of Gli-15 in gliadin was the highest, and the content of Gli-9 was the lowest. The TDS value of Gli-9 was the highest(336.0), and the TDS value of Gli-15 was the lowest(52.0). The electrical conductivity of Gli-9 was the highest,which was 7.54 times the lowest value of Gli-11. The zeta potential of Gli-9 was -25.2 mV, and the zeta potential of the Gli-15 was -7.64 mV. However, the difference in the p H values was not significant. The results of UV spectrum and FTIR analysis showed that the secondary structures of the Venn components had significant differences. The results of the XRD patterns indicated that the Venn components might not be a single substance. The results of CLSM images implied that the molecular interactions among the components were varied. Hence, the results could provide research materials and basic data for deep processing and utilization of gliadin.

Wheat gluten protein and its impacts on wheat processing quality

Before the advent of the wheat genomic era, a wide range of studies were conducted to understand the chemistry and functions of the wheat storage proteins,which are the major determinants of wheat flour the suitability of wheat flour for various end products, such as bread, noodles and cakes.Wheat grain protein is divided into gluten and non-gluten fractions and the wheat processing quality mainly depends on the gluten fractions.Gluten provides the unique extensibility and elasticity of dough that are essential for various wheat end products.Disulfide bonds are formed between cysteine residues,which is the chemical bases for the physical properties of dough.Based on the SDS-extractability, grain protein is divided into SDS-unextractable polymeric protein(UPP)and SDS-extractable polymeric protein.The percentage of UPP is positively related to the formation of disulfide bonds in the dough matrix.In the wheat genomic era, new glutenins with long repetitive central domains that contain a high number of consensus hexapeptide and nonapeptide motifs as well as high content of cysteine and glutamine residues should be targeted.