Maltase activity and dough rising ability of baker’s 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 °C worsened dough-rising ability; nevertheless, at the same time, a good value of maltase activity – 26.0 nmol⋅min^-1⋅mg^-1 was found. Dough-rising ability and maltase activity are strongly influenced by pH. The highest maltase activity, 68 nmol⋅min^-1⋅mg^-1, was obtained at pH 6.0, which improves the dough-rising ability to 55 cm³ CO₂. The concentration of DO affects the fermentation activity of the strain Saccharomyces cerevisiae 3: the metabolism became oxido-fermentative at less than 40% DO and maltase activity and dough-rising ability increased up to 43.5 nmol⋅min^-1⋅mg^-1 and 56 cm³, respectively. The results indicate that dough-rising ability and maltase activity increased as the temperature increased, and as the concentration of DO decreased. A direct correlation between maltase activity and dough-rising ability was found. Received: 24 October 1996