The quest for celiac-safe wheat

Gluten proteins from wheat have the unique property to interact with each other and form a network in dough preparation. In this gluten network gas bubbles can be retained that are produced by yeast, which is added during dough preparation. The result is a voluminous, viscoelastic dough for bread making. Besides these network forming properties, gluten proteins contain remarkably high amounts of the amino acids proline and glutamine. Therefore, these proteins can not be degraded completely in the human gastrointestinal tract and so called epitopes are generated in the small intestine after ingestion of gluten containing foods such as bread and cookies. Intolerance to gluten proteins can cause inflammation of the small intestine, which leads to villous atrophy (flatten mucosa) and malabsorption. This intolerance to gluten proteins is also called celiac disease. The with celiac disease occurring inflammation can lead to many symptoms such as malnutrition, weight loss, stomach pain, diarrhea, dermatitis and in the worst case lymphoma. In children, celiac disease can cause growth retardation. Gluten proteins from rye and barley, because of their similarity to gluten proteins from wheat and high proline and glutamine content, can also cause celiac disease. Celiac disease patients therefore have to avoid life-long all food products containing wheat, rye, and barley (gluten-free diet). Not only gluten protein intake but also genetic susceptibility is necessary to develop celiac disease. Therefore, relatives of celiac disease patients have a highly increased risk to develop celiac disease. About 0.52% of the Western population suffers from celiac disease of which 7097% is undiagnosed, and the prevalence of celiac disease is still increasing. The reason for this may be the consumption of many bread, cookie and pasta products, but also because wheat constituents, such as gluten and starch, are increasingly used as food additive in soups, sauces, sausage, candy, ice-cream, and even in medicines. Because bread wheat originated thousands of years ago by fusion of three different grass species, many different gluten proteins exist. Pasta wheat originated from two of the three grass species and lacks the species that contains most of the celiac disease epitopes. Not all gluten proteins can be removed because baking properties might be lost. For analysis of the presence of celiac disease epitopes, it is important that all gluten proteins are extracted from the wheat kernels. Therefore, an extraction protocol was developed to extract as many gluten proteins as possible, which allows analysis of many samples at the same time. Because thousands of different wheats exist that have never been tested for celiac disease epitopes, this extraction and detection method was applied to analyze whether modern wheats, which are used by breeders, exist with lower amounts of celiac disease epitopes. These modern wheats were subsequently compared to old wheats collected from all over the world. From these analyses it seemed that there was an increase in celiac disease epitopes in modern wheats. This might be the reason for the increase of prevalence of celiac disease. For future breeding of bread wheat it is important to select and breed not only for high yield, disease/pest resistance, and baking quality, but also for the (reduced) presence of relevant celiac disease epitopes. In older bread and pasta wheats, we observed that fewer celiac disease epitopes are present. Knowing this, a more celiac-safe bread wheat could be developed by performing crossings with a selection of wheats. In the analysis of wheat lines that miss specifically genetic parts of one of the three grass species from which bread wheat evolved, it appeared that if the part is removed that encodes celiac disease epitopes to which most patients respond, the dough properties improved compared to the control dough. By addition of similar proteins from oat (avenins), the dough properties improved even more. These gluten proteins from oat are tolerated by most celiac disease patients. The results show that it is feasible to develop wheat that contains less celiac disease epitopes without decreasing dough properties. Celiac disease patients, however, respond differently to different celiac disease epitopes which complicates the development of wheat that is suitable for all celiac disease patients. The research performed in this thesis shows that selection of wheat for the presence of celiac disease epitopes is extremely relevant because it can reduce the number of celiac disease patients in the future. At the same time, we demonstrate that celiac-safe wheat can still maintain good baking properties. Diagnosed celiac disease patients will benefit as well from celiac-safe wheat because exposure to ‘hidden’ gluten proteins will decrease. <br/

Presence of celiac disease epitopes in modern and old hexaploid wheat varieties: wheat breeding may have contributed to increased prevalence of celiac disease

Gluten proteins from wheat can induce celiac disease (CD) in genetically susceptible individuals. Specific gluten peptides can be presented by antigen presenting cells to gluten-sensitive T-cell lymphocytes leading to CD. During the last decades, a significant increase has been observed in the prevalence of CD. This may partly be attributed to an increase in awareness and to improved diagnostic techniques, but increased wheat and gluten consumption is also considered a major cause. To analyze whether wheat breeding contributed to the increase of the prevalence of CD, we have compared the genetic diversity of gluten proteins for the presence of two CD epitopes (Glia-α9 and Glia-α20) in 36 modern European wheat varieties and in 50 landraces representing the wheat varieties grown up to around a century ago. Glia-α9 is a major (immunodominant) epitope that is recognized by the majority of CD patients. The minor Glia-α20 was included as a technical reference. Overall, the presence of the Glia-α9 epitope was higher in the modern varieties, whereas the presence of the Glia-α20 epitope was lower, as compared to the landraces. This suggests that modern wheat breeding practices may have led to an increased exposure to CD epitopes. On the other hand, some modern varieties and landraces have been identified that have relatively low contents of both epitopes. Such selected lines may serve as a start to breed wheat for the introduction of 'low CD toxic' as a new breeding trait. Large-scale culture and consumption of such varieties would considerably aid in decreasing the prevalence of CD

Active Brownian Particles. From Individual to Collective Stochastic Dynamics

We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte

Hoe gevoelig tarwe en gluten liggen

In veel westerse landen groeit de aandacht voor tarwe en gluten. Ook mensen zonder tarweallergie of coeliakie lijken tarweproducten steeds vaker links te laten liggen. Samen met universiteiten en onderzoeksinstanties brengt het Nederlands Bakkerij Centrum de oorzaken, feiten en alternatieve mogelijkheden in kaart met als doel tot oplossingen voor de korte en lange termijn te komen

Quantification of Celiac Disease Gluten Epitopes

Scientists have published a novel method in the Journal of Chromatography A to detect multiple celiac disease-epitopes in wheat extracts simultaneously using liquid chromatography–multiple reaction monitoring mass spectrometry (LC–MRM–MS).1 Celiac disease is caused by an immune response in the small intestine from eating gluten proteins. An enzyme-linked immunosorbent assay (ELISA) is the standard testing method for food, but this can be inaccurate and does not differentiate between gluten proteins. Lead author Hetty van den Broeck told The Column: “This newly developed method based on mass spectrometry quantifies specifically celiac disease stimulating epitopes. This is not possible by ELISA, which detects gluten proteins in general by using a monoclonal antibody. Mass spectrometry allows specific detection and quantification of multiple CD-epitopes at the same time. This is necessary because of the complex genome of bread wheat and the many different CD-epitopes to which CD-patients can respond differentially.” In the current study, gluten extracts were prepared from wheat and extracted prior to LC–MRM–MS analysis. The authors developed the method to detect peptides known to induce the strongest immune response, as well as peptides with amino acid substitutions that make them harmless. The method was able to quantify different peptide isoforms, showing that a modern wheat variety, Toronto, contained the highest level of CD immunogenic peptides. The team are continuing their work to test and select reduced immunogenic wheat varieties, van den Broeck told The Column. She said: “We are also working on the development of screening body fluids from CD-patients for the presence of these epitopes or other specific peptide biomarkers for CD.”— B.

Glutenvrij ? Pils onde de loep

Gluten meten in gehydrolyseerde en gefermenteerde voedingsmiddelen – zoals pils – is lastig. De door de Codex Alimentarius gevalideerde test onderschat het gehalte gluten in deze producten. Een uitgebreide LC-MS/MS-analyse geeft gedetailleerde informatie over de aanwezige coeliakie-stimulerende gluten in pils. Met deze gegevens is een geschikte test te ontwikkelen