Search

The opportunities of molecular genetic approaches to manage the wheat grain's technological properties, influencing the quality of end products of bread industry, were considered within this review. At present, the traditional range is crowded out with an increase in grain production, the quality of the mass varieties of bread is deteriorating, and tens of different substances of biological and chemical origin are used as improvers in bread baking. Meanwhile, wheat's genetic potential allows us to create varieties for the production of grain with technological characteristics suitable for high-quality bread production. Multiple examples of the creation of varieties for the production of 1st and 2nd class grain exist in the history of domestic breeding; modern molecular genetics suggest approaches that in combination with traditional breeding methods enable the accelerated creation of new varieties adapted to the conditions and requirements of the baking industry by using the natural genetic potential of wheat. The authors summarized the data on the diversity of the requirements imposed on the grain and flour to be eventually used in different foods. The statistical data on the volume and structure of the grain quality in Russia from 2011 to 2014 were analyzed. A significant deformation of the quality structure of the produced wheat grain in favor of less valuable classes was detected. A short retrospective analysis of the studies in the field of wheat genetics that demonstrates the role of genetic factors in the development of technological properties of grain and flour was conducted. Different approaches to accelerated breeding of varieties with specified properties for the prospect of developing studies in the field of plant molecular genetics were considered. The examples illustrating the possibility and expedience of using DNA diagnostics methods at different stages of the process, during which the genetic potential (inherent in the gene pool of food crops) is realized and affects the final product quality, are given. The results of molecular genetic studies on determining the localization and structure of the genes involved in developing the technological properties of the wheat grain (the content of protein and wet gluten, milling properties, rheological properties of the flour and dough, flour color, and starch properties) were considered. The data on diagnostic DNA markers, suitable for the efficient selection of genotypes instead of the time-consuming analysis of technological characteristics at intermediate breeding stages, were summarized. Thus, the information on bread wheat's genetic potential and modern technological approaches, which constitute the basis for a change of the direction from increased chemicalization towards a softer and more organic effect on the quality of the main raw material and products in the entire 'grain-flour-bread' food chain, is summarized. [ABSTRACT FROM AUTHOR]

It is shown that the rate of the genotype's impact in the total impact of all other factors dictating the rate and variability of characteristics depending on the population varies with respect to the grain weight per area unit from 18.3 to 37.6%, the total grain hardness from 9.6 to 27.2%, the content of gluten in flour from 8.8 to 23.7%, and the IDK-1 (Gluten Deformation Gauge) rate from 8.5 to 48.1%. [ABSTRACT FROM AUTHOR]

Celiac disease (CD) is a permanent gastrointestinal disorder characterized by the intolerance to a group of proteins called gluten present in wheat, rye, barley, and possibly oats. The only therapy is a strict lifelong gluten-free diet. The standard method for gluten determination in foods produced for CD patients is the R5-enzyme-linked immunosorbent assay (ELISA) as proposed by the recent Codex Alimentarius Draft Revised Standard. This test is based on the determination of prolamins, the alcohol-soluble proteins of gluten, and is available as a sandwich ELISA for intact proteins and as a competitive ELISA for gluten-derived peptides. While the suitability of the sandwich ELISA including a wheat prolamin (gliadin) reference for calibration has been shown by various studies and a ring test, the competitive ELISA still lacks a convenient reference for the quantitation of gluten peptides in fermented cereal foods (e.g., sourdough products, starch syrup, malt extracts, beer). Therefore, the aim of the present study was to prepare a suitable reference for the quantitation of partially hydrolyzed gluten in fermented wheat, rye, and barley products. The prolamin fractions from barley (hordein) and rye (secalin) were isolated from corresponding flours by means of a modified preparative Osborne fractionation. The prolamin fraction from wheat was obtained as reference gliadin from the Prolamin Working Group. The prolamin fractions were successively digested by pepsin and trypsin or pepsin and chymotrypsin procedures, which have been used for CD-specific toxicity tests on cereal storage proteins for many years. The protein/peptide content (N × 5.7) of the prolamin fractions and digests, which was the basis for the calculation of the gluten content by means of ELISA, varied between 67.1% and 96.0%. The prolamin fractions and enzymatic digests were then tested for their response in both sandwich and competitive assays. Intact prolamins responded similarly in both ELISA showing no important differences between the cereals. In the case of digested proteins, however, the sandwich ELISA was considerably less sensitive than the competitive ELISA. The former provided approximately 40% and the latter 70% of the signal intensity obtained with the intact prolamins. Thus, the combination of the competitive ELISA and the enzymatic digests of prolamin fractions as reference was considered to be an adequate system for the analysis of partially hydrolyzed gluten. The limit of detection using a peptic-tryptic hordein digest as reference was 2.3 µg prolamin equivalent per milliliter, and the limit of quantitation was 6.7 µg prolamin equivalent per milliliter. This system was applied for the determination of gluten equivalents in five commercial beverages based on fermented cereals. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Presently, the only essential therapy of celiac disease (CD) is the permanent strict withdrawal of gluten from the diet. With respect to gluten containing foods from wheat, rye, barley, and oats, CD patients have to consume surrogates that must be gluten-free according to the “Codex Alimentarius Standard for Gluten-Free Foods”. The recent “Draft Revised Standard” proposes a gluten threshold of 20 mg per kg gluten-free product. For gluten quantitation, the alcohol-soluble prolamins should be extracted and analyzed by an immunochemical method; the amount of gluten is calculated by multiplying the prolamin content by the factor of 2. To investigate, whether this calculation is valid in any case of contamination of gluten-free products by wheat, rye, barley, and oats, wholemeal or white flours from common wheat, spelt, durum wheat, kamut, emmer, einkorn, rye, barley and oats were analyzed for the ratio of prolamins to glutenins (PROL/GLUT) by a combination of extraction and reversed-phase HPLC procedures. Additionally, different industrial wheat starches were analyzed for their prolamin and total gluten content using different extraction and concentration steps followed by gel permeation HPLC. The results for the cereal flours revealed that the ratio PROL/GLUT was generally higher than 1.0 as proposed by the “Draft Revised Standard” and strongly influenced by cereal species and variety. Common wheat showed the lowest ratio (1.5–3.1), followed by oats and spelt (1.7–3.3), barley (1.4–5.0), durum wheat and kamut (3.1–3.4), emmer (3.5–7.6), rye (6.3–8.2), and einkorn (4.0–13.9). In any case, the gluten content of gluten-free products contaminated with CD activating cereals was generally overestimated, when the prolamin content was multiplied by the factor of 2. In extreme cases, e.g., contamination with rye, the overestimation amounted to 72–79%. Completely different PROL/GLUT ratios were found in ten commercial wheat starches ranging from 0.2 to 4.9. Obviously, the quality of wheat cultivars used for starch production and/or different process parameters, e.g., washing steps, influenced the composition of gluten proteins adherent to starch granules. For wheat starch, the calculation of the gluten content by 2 × PROL may either lead to underestimation (−71% at most) or overestimation (+66% at most). In conclusion, this calculation is invalid; therefore, a future task will be the development of immunoassays with antibodies against all types of storage proteins from wheat, rye, barley, and oats. [ABSTRACT FROM AUTHOR]