BAKERY PRODUCTS WITH THE ADDITION OF SOYBEAN FLOUR AND THEIR QUALITY AFTER FREEZER STORAGE OF DOUGH

Abstract

The aim of this study was to observe the impact of adding 30% of flour from soya bean to the wheat flour T 650 on the quality of immediately baked products and products stored one, three and six months in a freezer at the temperature of -18° and then baked. Rheological properties of wheat and composite flour by means of Farinograph, Extensograph, and Amylograph were also evaluated. Based on the farinograph evaluation of composite flour (70% of wheat flour + 30% soybean flour) it was found that the formed mixture was hydrated more slowly than the pure wheat flour, time of dough development was about 6.5 minutes longer than that for pure wheat flour, and a value of water binding was higher by 12.4% compared with wheat flour. Created dough could be characterized as strong, holding long enough optimum of its rheological properties. By means of extensographic evaluation of composite flour it was found that it has lower extensographic energy, less resistance and lower tensibility compared to wheat dough, which led to insufficient volume of products. By amylogram it was found that composite flour has higher enzymatic activity compared to wheat flour, nevertheless both flours could be characterized as suitable for leavened bakery products. Addition of gross non-defatted soy flour at 30% had a significant impact on technological quality of loaves baked during the baking experiments. Compared with loaves of wheat flour, the lower bread volume, specific volume and volume yield, and less satisfactory cambering was found. The effect of freezing on dough in the case of wheat flour showed the gradual reduction of the quality parameters of the loaves baked from such dough after freezing time lasting for 1, 3 and 6 months. In the case of the composite flour, the decrease of quality was found only after freezing lasting 3 and 6 months. One-month freeze did not cause the declination of quality, to the contrary, even a slight increase of loaf volume was observed.