MALTASE ACTIVITY AND DOUGH RISING ABILITY OF BAKERS YEASTS OBTAINED AT DIFFERENT GROWTH-CONDITIONS DURING THE MATURATION STAGE

The effects of temperature, pH and dissolved oxygen (DO) at the final production stage on the quality of baker's yeast were studied. It was noted that an increase of temperature above 37 degrees C worsened doug hrising ability; nevertheless, at the same time, a good value of malta se activity - 26.0 nmol . min(-1) . mg(-1) was found. Dough-rising abi lity and maltase activity are strongly influenced by pH. The highest m altase activity, 68 nmol . min(-1) . mg(-1), was obtained at pH 6.0, w hich improves the dough-rising ability to 55 cm(3) CO2. The concentrat ion of DO affects the fermentation activity of the strain Saccharomyce s cerevisiae 3: the metabolism became oxide-fermentative at less than 40% DO and maltase activity and dough-rising ability increased up to 4 3.5 nmol . min(-1) . mg(-1) and 56 cm(3), respectively. The results in dicate that dough-rising ability and maltase activity increased as the temperature increased, and as the concentration of DO decreased. A di rect correlation between maltase activity and dough-rising ability was found.