Figure 2.

The evolved strains show increased freeze tolerance in flour‐based dough. Molasses‐plate‐grown cells of the parental CR and evolved CR19 and CR20 baker's yeast strains were used to prepare lean dough as described in the Experimental procedures section. Samples were quickly frozen at −80°C for 1 h and stored at −20°C for 21 days. Then, the frozen dough (grey bars) was left to thaw at 30°C for 30 min and CO₂ production was recorded in a home‐made fermentometer (Chittick apparatus). Unfrozen samples (black bars) were used as control. Values are expressed as ml of CO₂ produced after 180 min of dough fermentation and represent the means of at least three independent experiments. The error was calculated as described in Fig. 1.