Out of the six HMW-GS genes, 1Ay is usually not expressed in bread wheat cultivars. In the current study, an active 1Ay gene has been integrated into two Australian wheat cultivars, Livingston and Bonnie Rock, through conventional backcross approach. Three sister lines at BC4F4 generation for each cross were obtained and underwent a series of quality testing. Results show that the active 1Ay subunit increased the amount total protein, Glutenin/Gliadin ratio and unextractable polymeric protein. The expressed 1Ay also resulted in up to 10% increase of gluten content, 5% increase of glutenin, and hence increased the HMW-to LMW-GS ratio without affecting the relative amount of other subunits. Milling yield and Flour swelling were decreased in the Livingston lines and remained mostly unchanged for Bonnie Rock. Alveograph result showed that Ay improved dough strength in Livingston and dough extensibility in Bonnie Rock. Zeleny sedimentation value was found to be higher in all three lines of Bonnie Rock but only in one of Livingston derivatives. The dough development time and peak resistance, determined on the micro Z-arm mixer were increased in most cases. Overall, the integration of Ay subunit showed significant positive effects in bread making quality.

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Handling major hypersensitivity reactions (e.g. celiac disease) triggered by proteins of wheat and other cereals is a challenging task for healthcare systems, legislative forces and the related fields of food analysis as well. In spite of the fact that there are available official threshold levels for labelling the absence of gluten, which is considered to be the toxic protein fraction of wheat, barley and rye, validation of the analytical methodology supporting regulatory requirements is currently problematic. The main limiting factors of method validation are the lack of reference methods and reference materials. The objective of this study was to provide a solution to this problem. An incurred reference material in a model food matrix was developed and studied by commercially available ELISA test kits as a part of the activity of the Food Allergen Working Group within the FP6 funded EU project MoniQA. After successful completion of the reference material development process, the incurred material was used as a basis of a comparative study examining the performance and applicability of seven commercially available ELISA kits designed for quantification of gluten/gliadin. In certain cases the obtained data showed discrepancies from the expected gliadin content that may carry both a food safety and an economic relevance. The evaluation of the effects of heat treatment on the analytical results is also presented, highlighting the fact that the food processing steps may have a considerable impact on the analytical data, thus should be carefully handled during method development and validation.

Celiac disease and wheat allergy are the most common adverse reactions triggered by cereal proteins, mainly gluten, which is one of the 14 allergenic food ingredients that must be labeled on food products in the European Union (EU). To meet the requirements of this regulation, reliable analytical methodology for proper quantification of gluten is necessary. However, validation of presently used methods (ELISA and lateral flow device) is limited partly due to the lack of reference methods and incurred reference materials. To solve this problem, the goal of our work was to develop an incurred reference material for the quantification of gluten under the auspices of EU-FP6 funded Network of Excellence MoniQA. During this work, we produced a processed model product (cookie) containing gliadin (major allergenic fraction of gluten) in a defined amount. This paper addresses the development process of this material together with the associated problems (insufficient homogeneity and low recovery) and their solutions. As a result, an incurred food matrix was produced on a laboratory-scale with a potential use as a reference material. The model product was tested by an ELISA method followed by a comparative study of commercially available ELISA kits to investigate the applicability of the product. Preliminary results of this study are also presented.

Physicochemical and functional properties of arabinoxylans (AXs) can be significantly influenced by their isolation method. Finding balanced process conditions that allow optimal extraction yields while preserving AXs functionality is a challenge. The aim of this study was to determine the effect of different chemical solvents with neutral and alkaline pH on the intrinsic properties and extraction yield of AXs isolated from rye bran. Additionally, the application of xylanases and other cell wall degrading enzymes (Pentopan Mono BG, Deltazym XL‐VR, Viscoflow BG) to solubilize bound AXs was investigated. Results show that the use of Ca(OH)2 for isolation was superior to water and Na2CO3, as it selectively solubilized AXs and delivered isolates with a purity of up to 43.92% AX and a moderate ferulic acid (FA) content (209.35 ± 16.79 mg FA/100 g AX). Application of xylanases was further able to duplicate these achieved AX yields (7.50 to 9.85g AX/100 g bran). Additionally, isolates displayed highest ferulic acid contents (445.18 to 616.71 mg FA/100 g AX) and lowest impurities in comparison to chemical extracted AXs. Rheological characterization of the isolates showed a pronounced shear thinning behavior which fitted well to the power‐law model (R 2 > 0.989). Differences in pseudoplasticity of the isolates suggested that structural and chemical properties might have been responsible for this behavior.

Improving the nutritional quality and health benefits of food has been of increasing

Wheat grain proteins responses to mixing and thermal treatment were investigated using Mixolab-dough analysis systems with flour from two cultivars, Ventura-26 (normal amylose content) and Ventura-19 (reduced amylose content). Size exclusion high performance liquid chromatography (SE-HPLC) and two-dimensional gel electrophoresis (2-DGE) analysis revealed that, stress associated and metabolic proteins largely interacted with dough matrix of Ventura-26 after 26min (56°C); gliadins, avenin-like b proteins, LMW-GSs, and partial globulins showed stronger interactions within the dough matrix of Ventura-26 at 32min/C3 (80°C), thereafter, however, stronger protein interactions were observed within the dough matrix of Ventura-19 at 38min/C4 (85°C) and 43min (80°C). Thirty-seven proteins associated with changes in dough matrix due to reduced amylose content were identified by mass spectrometry and mainly annotated to the chromosome group 1, 4, and 6. The findings provide new entry points for modifying final product attributes.

Background: Rye arabinoxylans (AXs) might be used as baking improvers for gluten-free (GF) bread. However, their extraction process still needs to be improved. Objective and methods:The aim of this study was to simplify AX extraction of rye bran by varying temperature and pH and evaluate its chemical and rheological properties for application in GF bread. Results and conclusion:The results demonstrated that higher amounts of AX and impurities were extracted with the increasing pH and temperature. AX yield reached values up to 3.3 g AX/100 g bran. Highest ferulic acid (FA) content (117.27 ± 1.46 mg/100 g) was achieved at the mildest extraction conditions (30 °C and 0.17 M NaOH). A/X ratio of isolates ranged between 0.53 and 0.57 and the gluten content between 81.30 and 216.78 ppm. Rheological measurements revealed typical pseudoplastic behavior of isolates. AX extracted at 30 °C and 0.17 M NaOH showed a slightly higher initial viscosity in comparison with the other isolates but was still inferior to carboxylmethylcellulose (CMC) and hydroxypropyl methylcellulose (HPMC).