The co-occurrence of the major Fusarium mycotoxin deoxynivalenol (DON) and its conjugate deoxynivalenol-3-glucoside (DON-3-Glc) has been documented in infected wheat. This study reports on the fate of this masked DON within milling and baking technologies for the first time and compares its levels with those of the free parent toxin. The fractionation of DON-3-Glc and DON in milling fractions was similar, tested white flours contained only approximately 60% of their content in unprocessed wheat grains. No substantial changes of both target analytes occurred during the dough preparation process, i.e. kneading, fermentation, and proofing. However, when bakery improvers enzymes mixtures were employed as a dough ingredient, a distinct increase up to 145% of conjugated DON-3-Glc occurred in fermented dough. Some decrease of both DON-3-Glc and DON (10 and 13%, respectively, compared to fermented dough) took place during baking. Thermal degradation products of DON, namely norDON A, B, C, D, and DON-lactone were detected in roasted wheat samples and baked bread samples by means of UPLC-Orbitrap MS. Moreover, thermal degradation products derived from DON-3-Glc were detected and tentatively identified in heat-treated contaminated wheat and bread based on accurate mass measurement performed under the ultrahigh mass resolving power. These products, originating from DON-3-Glc through de-epoxidation and other structural changes in the seskviterpene cycle, were named norDON-3-Glc A, B, C, D, and DON-3-Glc-lactone analogically to DON degradation products. Most of these compounds were located in the crust of experimental breads.

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Papoušková L., Capouchová I., Kostelanská M., Škeříková A., Prokinová E., Hajšlová J., Salava J., Faměra O. (2011): Changes in baking quality of winter wheat with different intensity of Fusarium spp. contamination detected by means of new rheological system mixolab. Czech J. Food Sci., 29: 420-429.The aim of our work was to assess the possibility of detecting the changes in the baking quality of winter wheat with different levels of Fusarium spp. contamination using a new rheological system Mixolab, and to determine the correlations between the Mixolab characteristics and other quality parameters of wheat flour and grain. The standard technological characteristics (crude protein, Zeleny sedimentation index, wet gluten, falling number), loaf volume, shape features of bread (height and diameter), Mixolab parameters, and mycotoxin deoxynivalenol (DON) content were determined in 3 winter wheat cultivars (Akteur -quality group E -elite; Eurofit -quality group A; Meritto -quality group B) with different levels of Fusarium spp. contamination (8 variants) in two years. Increasing intensity of Fusarium spp. contamination evidently worsened the rheological quality and its negative effects on protein and mainly on the starch part of the grain was obvious in Mixolab curves. High correlations were found between Mixolab characteristics and standard technological parameters, as well as between Mixolab parameters and the main baking criterion -loaf volume.

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ABSTRAKT Detekce Tilletia controversa a Tilletia caries v pšenici pomocí PCRTilletia controversa and Tilletia caries byly specificky detekovány v celých rostlinách pšenice pomocí PCR s primery TILf (5´-CAC AAG ACT ACG GAG GGG TG-3´) a TILr (5´-CTC CAA GCA ACC TTC TCT TTC-3´). DNA z neinfikovaných rostlin pšenice, žita, ječmene a tritikale nebyla amplifikována. Přirozená infekce rostlin houbami Alternaria spp., Erysiphe graminis and Fusarium spp. prokázala specifitu testu pro houby z rodu Tilletia, neboť ani v tomto případě nevznikal žádný nespecifický produkt. Tato metoda může být velmi užitečná pro producenty osiva a pracovníky ÚKZÚZ pro kontrolu kvality osiva.