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Mechanical flour modification and its effect on saccharide formation and dough functionality
S. HACKENBERG (1), M. Jekle (1), T. Becker (1) (1) Technical University of Munich, Institute of Brewing and Beverage Technology, Freising, Germany.

For mechanical flour modification, wheat flour (ground by a roller mill) with a mechanical starch modification (MSM) of 4.78% was re-ground by a ball mill for four more MSM levels. Grinding was performed by varying the rotational speed and retention time until a significantly higher MSM level was reached. The MSM level was determined during grinding using the amperometrically method provided by Chopin (SDmatic; AACC 76-33). The water holding capacity (WHC) showed a linear rise as a function of MSM (R2=0.82). Furthermore, the water absorption of the samples was measured according to AACC method 54.21.02. The saccharide concentration, which influences yeast activity as well as gelatinization properties of starch, was analyzed in a flour-water-suspension as a function of fermentation time (0, 5, 10, 20, 60, 120, 180 min) by using a HPAEC-ED. Changes in the maltose content during fermentation were primarily responsible for an increasing saccharide concentration with rising MSM due to better hydrolysis by amylolytic enzymes. Maltose concentration increased with enhanced MSM levels and fermentation time. From suspension up to dough a reduction of water leads to a higher saccharide concentration after fermentation at the same MSM level. A comparison of the maltose concentration of yeasted and non-yeasted dough produced with varying water addition showed a lower maltose metabolization with higher dough hydration. However, varying MSM levels at a constant water addition resulted in nearly the same maltose metabolization of yeast after fermentation, despite higher substrate availability. In dough-model-systems changes in maltose concentration had an effect on the rheological dough properties measured during microbaking tests in a rheometer. In this regard, maltose content had an effect on gelatinization properties during baking.