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Grano monococco: sua caratterizzazione per la produzione di pane e biscotti in relazione alla composizione della subunità proteica

by luciano

La ricerca ha evidenziato, attraverso test per la realizzazione di pane e biscotti, le migliori varietà di monococco tra le 24 prese in esame: tra queste le varietà ID140, ID280 e Id361 sono risultate le migliori per entrambi gli usi.

La ricerca riporta anche come, per le proprietà reologiche delle farine sia importante la presenza o assenza di un numero molto limitato di subunità della proteina di riserva evidenziando l’importanza delle LMW-GS (glutenine a basso peso molecolare) nella qualità della panificazione “.

Einkorn Characterization for Bread and Cookie Production in Relation to Protein Subunit Composition M. Corbellini, S. Empilli, P. Vaccino, A. Brandolini, B. Borghi, M. Heun, and F. Salamini. Cereal Chem. 76(5):727–733

Abstract
“Twenty-four einkorns were evaluated for agronomic traits in Italy and in Germany in replicated plot trials. After dehulling and milling, the harvested kernels, flour protein content, sedimentation volume, falling number, carotenoid, and dry gluten content were determined. Farinograph profiles were obtained with a farinograph and baking and cookie quality were evaluated with standard microtests. Significant differences in yield potential were observed between the two locations, with a three-fold increase in Germany as compared with Italy. One of the einkorn lines (ID529) had farinograph stability and degree of softening indices better than those of the control bread wheat. All the samples analyzed for breadmaking aptitude showed some degree of stickiness, but it was possible to handle the dough during the different steps of breadmaking. On average, cookies produced with einkorn flour were larger in diameter and thinner than those produced with soft wheat flour. The composition in α, β and γ-gliadins and in high molecular weight glutenin subunits was similar in all the lines. In contrast, the pattern exhibited in low molecular weight glutenin subunits correlated strictly with baking quality. In particular, the lines with bands arbitrarily designated a and b showed a high breadmaking poten- tial, while the lines lacking these bands had an ample range of variability but, on average, a much lower baking potential. Our data point to a simple genetic control of the breadmaking aptitude and indicate einkorn not only as a promising source of specialty foods but also as an ideal species for genetic investigations on wheat quality”.

NOTE:
LMW-GS: Glutenine a basso peso molecolare

Tabella estratta dalla ricerca:

Caratterizzazione elettroforetica delle proteine di riserva: glutenine e gliadine. Esse rappresentano, con le diverse rispettive bande, l’impronta genetica che ne definisce ed individua la varietà. (Tabella estratta dalla ricerca)

Le omega gliadine codificate dal genoma B1 del frumento exaploide possono anche ospitare epitopi della grave allergia alimentare WDEIA.

by luciano

“Omega-5 gliadins are a group of highly repetitive gluten proteins in wheat flour encoded on the 1B chromosome of hexaploid wheat. These proteins are the major sensitizing allergens in a severe form of food allergy called wheat-dependent exercise-induced anaphylaxis (WDEIA). The elimination of omega-5 gliadins from wheat flour through biotechnology or breeding approaches could reduce the immunogenic potential and adverse health effects of the flour. Susan B. Altenbach et al. BMC Plant Biology volume 18, Article number: 291 (2018)”

 

Il grano monococco ne è privo, vedi articolo : assenza della ω-5 gliadin nel monococco

Individuare simultaneamente i peptidi del glutine che sono più attivi nell’attivare il sistema immunitario dell’uomo

by luciano

Il metodo si propone di individuare, attraverso l’uso di specifici anticorpi, i peptidi più tossici invece che, come avviene con gli usuali metodi oggi utilizzati, il contenuto totale di glutine. Considerato che la ricerca è focalizzata anche nel produrre grani con minore quantità di peptidi tossici, così come utilizzare specifici pool di enzimi/batteri/ecc nella preparazione di prodotti con lo stesso scopo la possibilità di individuare e “pesare” solo la presenza, nel prodotto finito, dei peptidi più attivi diventa uno strumento molto utile. Lo studio evidenziato ripercorre la storia dei metodi finora utilizzati per quantificare il glutine nel cibo e presenta vantaggi e limiti del nuovo metodo. Tutti i metodi richiamati, compreso il nuovo metodo, sono stati sviluppati per poter certificare se un cibo è o meno sicuro per i celiaci ma il nuovo metodi diventa ancora più interessante per i soggetti sensibili al glutine NON celiaci e/o pre-celiaci. La frazione tossica dannosa per i celiaci è la stessa che nei soggetti sensibili al glutine NON celiaci (1) ma ha un impatto molto diverso e meno dannoso: il nuovo metodo è, dunque, utilissimo anche in questo caso con il vantaggio di poter avere una maggiore tolleranza nel risultato.

Simultaneously identify the gluten peptides that are most active in activating the human immune system.

The method aims to identify, through the use of specific antibodies, the most toxic peptides instead of, as with the usual methods used today, the total gluten content. Considering that the research is also focused on producing grains with smaller amounts of toxic peptides, as well as using specific pools of enzymes / bacteria / etc in the preparation of products with the same purpose, the possibility of identifying and “weighing” only the presence, in the final product, more active peptides become a very useful tool. The highlighted study traces the history of the methods used to quantify gluten in food and presents advantages and limitations of the new method. All the methods mentioned, including the new method, have been developed to be able to certify whether a food is safe for celiacs or not, but the new methods become even more interesting for non-celiac and / or pre-celiac gluten sensitive subjects. The toxic fraction harmful to celiacs is the same as in people who are sensitive to gluten NOT celiac (1) but has a very different and less harmful impact: the new method is, therefore, very useful also in this case with the advantage of being able to have a greater tolerance in the result.

Approfondimenti

 Immunochemical Detection Methods for Gluten in Food Products: Where Do We Go from Here?

Note:

(1) – Gluten Immunogenic Peptides as Standard for the Evaluation of Potential Harmful Prolamin Content in Food and Human Specimen.

Ángel Cebolla , María de Lourdes Moreno , Laura Coto and Carolina Sousa

Published: 5 December 2018

Grano Monococco, dicocco e grano duro

by luciano

Grano Monococco, dicocco e grano duro: non hanno la frazione “33mer” considerata la più attiva nell’attivare la risposta avversa del sistema immunitario nei soggetti celiaci. Anche per questo motivo sono i genotipi più adatti per le ricerche che hanno come scopo di “detossificare” le farine o di intervenire con particolari enzimi per idrolizzare i “peptidi tossici” comunque presenti; sono più adatti anche per i soggetti sensibili al glutine NON celiaci.

“Quantitation of the immunodominant 33-mer peptide from α-gliadin in wheat flours by liquid chromatography tandem mass spectrometry.

Kathrin Schalk , Christina Lang , Herbert Wieser , Peter Koehler  & Katharina Anne Scherf. Scientific Reports volume 7, Article number: 45092 (2017).

Abstract

Coeliac disease (CD) is triggered by the ingestion of gluten proteins from wheat, rye, and barley. The 33-mer peptide from α2-gliadin has frequently been described as the most important CD-immunogenic sequence within gluten. However, from more than 890 published amino acid sequences of α-gliadins, only 19 sequences contain the 33-mer. In order to make a precise assessment of the importance of the 33-mer, it is necessary to elucidate which wheat species and cultivars contain the peptide and at which concentrations. This paper presents the development of a stable isotope dilution assay followed by liquid chromatography tandem mass spectrometry to quantitate the 33-mer in flours of 23 hexaploid modern and 15 old common (bread) wheat as well as two spelt cultivars. All flours contained the 33-mer peptide at levels ranging from 91–603 μg/g flour. In contrast, the 33-mer was absent (<limit of detection) from tetra- and diploid species (durum wheat, emmer, einkorn), most likely because of the absence of the D-genome, which encodes α2-gliadins. Due to the presence of the 33-mer in all common wheat and spelt flours analysed here, the special focus in the literature on this most immunodominant peptide seems to be justified……Omissis…..

Analysis of durum wheat, emmer and einkorn

The 33-mer peptide was also analysed in two durum wheat and two emmer cultivars (genome AABB) as well as two diploid einkorn cultivars (genome AA) (Table 1). In each of these wheat species, the 33-mer was not detected (<LOD). In comparison to hexaploid common wheat, durum wheat, emmer, and einkorn do not contain the D-genome, which originated from hybridisation of T. turgidum dicoccum (genome AABB) with Aegilops tauschii (genome DD)36. The absence of the 33-mer peptide can be explained by the fact that this peptide is encoded by genes located in the Gli-2 locus on chromosome 6D, which is missing in durum wheat, emmer, and einkorn. Studies by Molberg et al. showed clear variations in intestinal T-cell responses between common wheat and tetra- or diploid species due to different degrees of T-cell immunoreactivity between the gluten proteins encoded on the A-, B-, and D-genome. Einkorn cultivars were only recognized by DQ2.5-glia-α1a-specific T-cell clones, but not by DQ2.5-glia-α1b- and DQ2.5-glia-α2-specific T-cell clones. Emmer and durum wheat cultivars were all recognized by DQ2.5-glia-α1a-specific T-cell clones, but only two out of four emmer cultivars and three out of ten durum wheat cultivars activated DQ2.5-glia-α1b- and DQ2.5-glia-α2-specific T-cell clones37. Consistent with our results, Prandi et al.38 found that the 33-mer was not present in durum wheat. As a consequence, this peptide was used as a marker peptide to identify the presence of common wheat in durum wheat flours. One durum wheat cultivar was also analysed by van den Broeck et al.33 and the 33-mer peptide was not detected either”. https://creativecommons.org/licenses/by/4.0/deed.it