Abstract
One of the most significant current discussions in dough fermentation is survivability and bioactivity of Saccharomyces cerevisiae. In this study, four samples of instant dry yeast (all the yeast strains are active dry type) were evaluated by epifluorescence light microscopy using 0.2 % fluorescein diacetate. Microbial tests were carried out in order to count the number of viable cells yeast. Gasograph used to measuring CO2 produced during fermentation. Bread volume and height were assessed. Yeast (A) had the highest number of green cells (178 ± 7) due to its more bioactivity as compared to types B, C and D (P<0.05) and yeast (D) had the lowest number of green yeast cells (48 ± 8). In microbial tests, the number of viable yeast in yeast (A) was highest (15×1010 cfu‧mg-1) and in yeast (D) was the lowest (9×1010 cfu‧mg-1). In gasography yeast (A) produced the highest amount of CO2 (163 ± 2 mL CO2/3h) and in yeast (D) produced the lowest amount of CO2 (140 ± 2 mL CO2/3h). Bread (A) (that made by yeast A) had the highest volume (132 ± 1.0 cm3) and height (4.8 ± 0.3 cm) and bread (D) (that made by yeast D) had the lowest volume (102 ± 6cm3) and height (3.7 ± 0.2 cm). High survivability and bioactivity of baker’s yeast leads to more CO2 production that leads to high volume and height in bread.