Assessment of the influence of gluten quality on highland barley dough sheet quality by different instruments.

This study was to compare the results of texture analyzer with those of farinograph and extensograph and determine whether texture analyzer could be used to evaluate the processing quality of highland barley flour (HBF) dough sheet. The farinograph and extensograph tests were used to determine the reconstituted flour properties, a texture analyzer was applied to measure the tensile strength (TS) of HBF dough sheet, and the content of glutenin macropolymer (GMP), free sulfhydryl (-SH) and secondary structure of protein and microstructure in HBF dough sheet were investigated. Furthermore, correlations between these parameters were determined by regression analysis and Pearson correlation coefficient. It was suggested that the reconstituted flours with a higher gluten index showed a higher farinograph quality number (FQN) and greater maximum resistance to extension (Rm ). HBF dough sheets with higher gluten index possessed higher GMP and lower free -SH contents, a more ordered secondary structure of protein, resulting in a more compact gluten network and a stronger TS. The regression and correlation analysis showed that TS was positively correlated with FQN and Rm . In addition, it was significantly correlated with the content of GMP, -SH, secondary structure of protein and gluten network. It was concluded that texture analyzer could be an alternative approach to evaluate the processing quality of HBF dough sheet. Moreover, the gluten index of flours could be used to predict the processing quality of HBF dough sheet.

Assessment of price and nutritional quality of gluten-free products versus their analogues with gluten through the algorithm of the nutri-score front-of-package labeling system.

Evidence has shown that the nutritional quality of gluten-free products (GFPs) is lower than that of non-GFPs. Our main objective was to compare the nutritional quality through nutritional profiles of foods underlying the Nutri-Score front-of-pack and the price of GFPs with respect to non-GFPs, and to evaluate whether there is a correlation between both parameters. Nutritional information of all products was obtained from the CELIACBASE database and the price through Spanish supermarkets websites. Global quality using the Nutri-Score algorithm and the price were compared between both types of products. GFPs do not always have poorer quality than their counterparts. A better quality of gluten-free pasta was correlated with the higher price but also a worse quality of gluten-free muesli was correlated with the higher price. The price of GFPs compared to non-GFPs was higher up to 391.5%. However, for ham and cheese pizza, ham pizza, Marie biscuits, and baby biscuits, the difference was not statistically significant. Generally, the price of GFPs did not correlate with better nutritional quality. Nutri-Score would ease the nutritional quality identification, empowering consumers and could also influence manufacturers to improve the nutritional quality of GFPs. Nowadays, given that many GFPs have poor nutritional quality, they should be included only occasionally in a balanced gluten-free diet.

Assessment of arsenic distribution, bioaccessibility and speciation in rice utilizing continuous extraction and in vitro digestion.

Rice, a staple food for half the world's population, easily accumulates arsenic (As). Research on As distribution in rice protein and starch and its relationship with rice As bioaccessibility remains limited. This study investigated As distribution, chemical composition, As bioaccessibility and speciation in rice by continuous extraction and in vitro digestion. Of the total As, 87.5-94.5% was in rice protein and 5.0-9.8% in rice starch. The As amount in different protein fractions decreased as follows: glutelin > globulin > albumin > prolamin. As(V), As(III) and DMA in rice were more bioaccessible in the small intestinal phase than the gastric phase, and almost all As(V) dissolved in the small intestinal phase. Bioaccessible As in gastrointestinal digestive solution and As mass in protein fractions (albumin, globulin, and glutelin) were significantly positively correlated (p < 0.05). These results illuminate the bioaccessibility of As to humans consuming As-contaminated rice and avoid overassessment.

Glutenin and Gliadin, a Piece in the Puzzle of their Structural Properties in the Cell Described through Monte Carlo Simulations.

Gluten protein crosslinking is a predetermined process where specific intra- and intermolecular disulfide bonds differ depending on the protein and cysteine motif. In this article, all-atom Monte Carlo simulations were used to understand the formation of disulfide bonds in gliadins and low molecular weight glutenin subunits (LMW-GS). The two intrinsically disordered proteins appeared to contain mostly turns and loops and showed "self-avoiding walk" behavior in water. Cysteine residues involved in intramolecular disulfide bonds were located next to hydrophobic peptide sections in the primary sequence. Hydrophobicity of neighboring peptide sections, synthesis chronology, and amino acid chain flexibility were identified as important factors in securing the specificity of intramolecular disulfide bonds formed directly after synthesis. The two LMW-GS cysteine residues that form intermolecular disulfide bonds were positioned next to peptide sections of lower hydrophobicity, and these cysteine residues are more exposed to the cytosolic conditions, which influence the crosslinking behavior. In addition, coarse-grained Monte Carlo simulations revealed that the protein folding is independent of ionic strength. The potential molecular behavior associated with disulfide bonds, as reported here, increases the biological understanding of seed storage protein function and provides opportunities to tailor their functional properties for different applications.

Safety Assessment of Hydrolyzed Wheat Protein and Hydrolyzed Wheat Gluten as Used in Cosmetics.

The Cosmetic Ingredient Review (CIR) Expert Panel (Panel) reviewed the product use, formulation, and safety data on hydrolyzed wheat protein and hydrolyzed wheat gluten, which function as skin- and hair-conditioning agents. The Panel determined that data from clinical and laboratory studies were sufficient to demonstrate that these ingredients will not elicit type 1 immediate hypersensitivity reactions in sensitized individuals and will not induce sensitization when the polypeptide lengths of the hydrolysates do not exceed 30 amino acids. The Panel concluded that hydrolyzed wheat gluten and hydrolyzed wheat protein are safe for use in cosmetics when formulated to restrict peptides to an average molecular weight of 3,500 Da or less.

Evaluation of gluten in gluten-free-labeled foods and assessment of exposure level to gluten among celiac patients in Lebanon.

The aim of the study was to evaluate gluten contamination in all the gluten-free (GF)-labeled food products sold in Lebanon. Over a 2-year period, a total of 173 food samples collected from 135 brand names were analyzed. Gluten contamination was detected in 33 of 173 (19%) samples, and its content ranged between 2.5 and >80 mg kg-1. In 10 of the 173 samples (6%), the quantity of gluten exceeded the upper limit of 20 mg kg-1. Out of the 10 contaminated products, eight (80%) were locally manufactured. Among these 10 products, eight (80%) were wheat-starch-based foods. Of the 40 brand names tested twice in 2014 and 2015, 15 (38%) showed significantly (p < .05) different gluten content between the 2 years. Using a food frequency questionnaire, exposure level to gluten through the contaminated products was evaluated among 15 celiac patients. Two patients reported consuming these products more than twice per week.

Assessment of molecular weight distribution of wheat gluten proteins for chapatti quality.

Size exclusion chromatography (SEC) was used to characterize molecular weight distribution pattern of gluten proteins of four Indian commercial wheat varieties in order to elucidate their influence on flour physicochemical, dough rheology and quality characteristics of chapatti. SEC profile of a wheat variety was segregated into five domains: peak I (130-30 kDa; glutenins), peak II (55-20 kDa; gliadins), peak III (28-10 kDa; low molecular weight gliadins), peak IV and V (<10 kDa; albumins and globulins). SEC results indicated that R/E ratio (r=0.745(∗∗) and r=-0.869(∗∗)), gluten index (r=0.959(∗∗) and r=-0.994(∗∗)), dough development time (r=0.830(∗∗) and r=-0.930(∗∗)) and dough stability (r=0.901(∗∗) and r=-0.979(∗∗)) were positively and negatively altered by peak I and II, respectively. Peak I (r=0.879(∗∗) and r=-0.981(∗∗)) and peak II (r=-0.744(∗∗) and r=0.995(∗∗)) substantially influenced the chapatti hardness and overall score, respectively.

Gluten content of medications.

PURPOSE: The establishment of a database for the identification of the presence of gluten in excipients of prescription medications is described. SUMMARY: While resources are available to ascertain the gluten content of a given medication, these resources are incomplete and often do not contain a source and date of contact. The drug information service (DIS) at Robert Wood Johnson University Hospital (RWJUH) determined that directly contacting the manufacturer of a product is the best method to determine the gluten content of medications. The DIS sought to establish a resource for use within the institution and create directions for obtaining this information from manufacturers to ensure uniformity of the data collected. To determine the gluten content of a medication, the DIS analyzed the manufacturer's package insert to identify any statement indicating that the product contained gluten or inactive ingredients from known sources of gluten. If there was any question about the source of an inactive ingredient or if no information about gluten content appeared in the package insert, the manufacturer of the particular formulation of the queried medication was contacted to provide clarification. Manufacturers' responses were collected, and medications were categorized as "gluten free," "contains gluten," or "possibly contains gluten." To date, the DIS at RWJUH has received queries about 84 medications and has cataloged their gluten content. CONCLUSION: The DIS at RWJUH developed a database that categorizes the gluten status of medications, allowing clinicians to easily identify drugs that are safe for patients with celiac disease.

Accuracy of ELISA detection methods for gluten and reference materials: a realistic assessment.

The determination of prolamins by ELISA and subsequent conversion of the resulting concentration to gluten content in food appears to be a comparatively simple and straightforward process with which many laboratories have years-long experience. At the end of the process, a value of gluten, expressed in mg/kg or ppm, is obtained. This value often is the basis for the decision if a product can be labeled gluten-free or not. On the basis of currently available scientific information, the accuracy of the obtained values with commonly used commercial ELISA kits has to be questioned. Although recently several multilaboratory studies have been conducted in an attempt to emphasize and ensure the accuracy of the results, data suggest that it was the precision of these assays, not the accuracy, that was confirmed because some of the underlying assumptions for calculating the gluten content lack scientific data support as well as appropriate reference materials for comparison. This paper discusses the issues of gluten determination and quantification with respect to antibody specificity, extraction procedures, reference materials, and their commutability.

Nutritional assessment of transgenic lysine-rich maize compared with conventional quality protein maize.

BACKGROUND: The gene sb401 encoding a lysine-rich protein has been successfully integrated into the genome of maize (Zea mays), its expression showing as increased levels of lysine and total protein in maize seeds. As part of a nutritional assessment of transgenic maize, nutritional composition, especially unintended changes in key nutrients such as proximates, amino acids, minerals and vitamins as well as in antinutrient (phytate phosphorus), and protein nutritional quality were compared between transgenic maize (inbred line 642 and hybrid line Y642) and conventional quality protein maize (QPM) Nongda 108. RESULTS: The contents of total protein, lysine, some other amino acids, several minerals and vitamin B2 in transgenic inbred line 642 and hybrid line Y642 were significantly higher than those in conventional QPM. Water-soluble protein and G2-glutelin were significantly promoted in transgenic maize Y642. CONCLUSION: Insertion of the lysine-rich sb401 gene increased the total protein and lysine content of transgenic maize varieties, leading to an improved amino acid score and therefore an improvement in the nutritive value of maize.

Gluten and gluten-free: issues and considerations of labeling regulations, detection methods, and assay validation.

Gluten is a commonly used cereal derivative found in bakery products, among other items. In some susceptible individuals, however, it triggers immune responses of different kinds; there is, to a lesser extent, the wheat allergy that is immunoglobulin E (IgE)-mediated and leads to histamine release and typical allergic symptoms. In this case, other water-soluble proteins, like albumins, are also involved. On the other hand, there is, more frequently, celiac disease (CD), where the gluten causes immune reactions in the intestines of certain individuals, leading to degeneration of villi, which typically leads to malabsorption of nutrients and, consequently, malnutrition. The only currently effective health strategy for affected consumers is avoidance of gluten-containing products, based on clear labeling rules. However, despite unanimously accepted Codex definitions by all member jurisdictions, the national implementation of equivalent laws shows significant differences. In the context of CD and in support of the gluten-free statement, regulatory enforcement, as well as manufacturers' quality controls are mostly based on analytical results. However, numerous methods are available, some of which have been validated better than others, and many provide different results on identical samples. Reasons include detection of different gluten components and variability in extraction efficiency due to different buffer compositions, especially from processed foods. Last but not least, the lack of reference materials is hindering the process of generating comparable data across different ELISA kits, as well as other methods. How can such data still be used to support a gluten-free claim? New methodologies, in particular mass spectrometric analysis of gluten derived peptides, are being introduced in numerous laboratories. This methodology is not only capable of detecting gluten derived peptides but can also differentiate between and quantitate wheat, barley, rye, and oat. This paper presents analytical limitations, as well as promising new approaches in support of industry and enforcement activities to ensure compliance with the gluten-free claim under the current regulatory framework.

Determining the gluten content of nonprescription drugs: information for patients with celiac disease.

OBJECTIVES: To determine whether the information on the gluten content of nonprescription drugs is readily available from the manufacturer/supplier, to identify how patients are directed on the product labeling to obtain answers to questions that they have about the nonprescription medication, and to determine the time needed to obtain information about the gluten content of the product when contacting manufacturers/suppliers. DESIGN: Descriptive, exploratory, nonexperimental study. SETTING: United States during July 2010. PARTICIPANTS: Manufacturers/suppliers of 41 nonprescription drug products. INTERVENTION: The packaging of the products was reviewed for information on gluten content. The manufacturer/supplier listed on each product's packaging was contacted using the phone number provided and questioned about the gluten content of the product. A uniform script was used for the telephone inquiry. The responses provided and the duration of the phone calls were documented. The manufacturer's websites also were reviewed for pertinent information. MAIN OUTCOME MEASURES: Gluten status of products, time spent on phone to determine gluten status, and availability of online information regarding gluten status. RESULTS: Information concerning the gluten content was not included on any of the products' packaging. The mean time required to receive a response was 6.2 minutes (median 5 minutes). A total of 15 products were reported to be gluten free; 13 products were not tested, but the manufacturer/supplier stated that they did not add gluten to the products; 9 products did not have any gluten added by the manufacturer/ supplier, but no guarantee was made that the raw ingredients were gluten free; 2 products contained gluten; and 2 products had no available gluten status information. Gluten information was found on product websites for a total of six products. Four of those six websites indicated gluten status that was different from the information provided via the telephone call with the manufacturer. CONCLUSION: Information concerning the gluten content of many nonprescription drugs is relatively easy for patients to obtain if the manufacturer/supplier is contacted. Although the time to obtain a response was quite short for many of the inquiries, it took a substantial amount of time to receive the requested information from some of the companies.

[Genetic analysis of contribution of low-molecular-weight glutenin subunits to dough strength in common wheat].

Locus-specific primers of low-molecular-weight glutenin subunit (LMW-GS) genes and gliadin bands tightly linked to LMW-GS genes were analyzed to evaluate the effect of LMW-GS genes on dough strength in common wheat (Triticum aestivum L.). Analysis of the F9 progeny from two crosses '99G45/Jing771' and 'Pm97034/J771' showed that the LMW-GS genes located at the Glu-B3 locus from the three parents had six Cysteine, but 'PB' (define) had a seven amino-acid deletion in the repetitive to 'GB' and 'JB' (define these abbreviations) and amino-acid substitution, two of which would be expected to cause changes in hydrophilicity.

Assessment of gliadin in supposedly gluten-free foods prepared and purchased by celiac patients.

BACKGROUND: The present study was designed to evaluate the presence of gliadin in homemade foods prepared by patients with celiac disease and/or their relatives, as well as in processed products consumed by such patients in São Paulo, Brazil, by enzyme immunoassay (EIA) and Western blot (WB) analysis. METHODS: One hundred ninety samples were analyzed: 108 homemade foods prepared in homes of patients with celiac disease, 81 processed products, and 1 positive control of homemade food. All samples were analyzed by EIA based on monoclonal antibodies to heat stable omega-gliadins and related prolamins from wheat, rye, and barley. Samples were also analyzed using the WB technique. RESULTS: Only one (0.9%) of 108 homemade foods contained detectable amounts of gliadin, as determined by EIA. Twelve of 81 processed products contained gliadin by EIA, as follows: 5 of 61 without gluten listed in the ingredients, 2 of 11 malt extracts, 1 of 2 wheat starches, 1 of 2 types of beer, and all 3 positive control products. Gliadin content of these products was between 4 and 10 mg of gliadin/100 g of product, except for the wheat starch sample (28 mg of gliadin/100 g) and all 3 samples with gluten (>4000 mg of gliadin/100 g). The positive control of homemade food contained 152 mg of gliadin/100 g. One hundred three of 190 samples were analyzed by WB, and 21 of these were gliadin positive. A comparison of results obtained by EIA and WB showed no statistical differences between the methods. CONCLUSIONS: The greater part of the foods prepared in homes of patients with celiac disease and most processed products supposed to be gluten-free did not contain gliadin. Therefore, celiac patients adequately prepare gluten-free homemade food and have the expertise to purchase processed gluten-free food in São Paulo, Brazil.

In vitro assessment of acetic-acid-soluble proteins (glutenin) toxicity in celiac disease.

Acetic-acid-soluble storage proteins from gluten of the bread wheat cv. Sprint 3 were fractionated by adsorption chromatography on 2000 A controlled-pore glass (CPG) beads, and glutenin polymers with molecular mass higher than 10(7) Da and free from monomeric gliadins were recovered. The glutenin polymers were found to consist of high-molecular-weight (HMW) and low-molecular-weight (LMW) glutenin subunits. Peptic-tryptic (PT) digests of glutenins were examined for their agglutination activity on human myelogenous leukemia K 562(S) cells, agglutination being strongly correlated with toxicity for the celiac intestine. The peptide fraction at a concentration of 1 g/L of culture medium was able to agglutinate 30% of K 562(S) cells, suggesting a moderate toxic effect. This toxicity may be accounted for by homologies in amino acid sequences between glutenin subunits and alpha/beta- and gamma-gliadins.