A comparative study on different methods for the evaluation of baker's yeast bioactivity

Abstract

Four samples of instant yeast powder were evaluated by epifluorescence light microscopy, microbial tests, gasography, the Henry-Simon pressure meter, and baking. All of the results showed that yeast (A) showed the highest number of green cells (178 +/- 7), the highest number of viable yeast (15 x 10(10) cfu/mg), the highest amount of CO2 production (163 +/- 2 mL/3 h and 875 +/- 3 mbar/3 h), and the highest volume (132 +/- 1 cm(3)) and height of the bread (5.0 +/- 0.3 cm) due to its higher bioactivity when compared to types B, C, and D (p < 0.05). The correlation study within the methods demonstrated that the Henry-Simon pressure meter was a faster, easier, inexpensive, and more accurate method than others. Therefore, it could be considered as an appropriate method to evaluate the fermentation activity of baker's yeast.