Effects of freezing rate and terminal freezing temperature on frozen croissant dough quality

Using frozen ready-to-bake dough is a very common practice in the industrial croissant production. However, the freezing process during the preparation frozen croissant dough can deteriorate its quality. In this study, we investigated the effects of the freezing rate (FR) and terminal freezing temperatures on the volume and firmness of croissants by analyzing frozen dough for yeast viability, thermal property changes, and internal microstructure integrity. Croissant dough samples were frozen at rates ranging from −0.72 to −3.56 °C min⁻¹ down to final temperatures of −20, −40, and −55 °C. Our results showed that the ice crystals normally forming in the dough during freezing, causing a lower yeast viability and croissants quality, were of smaller size when a rapid FR ≥ −3.19 °C min⁻¹ was used. Furthermore, a freezing termination temperature lower than −20 °C induced more yeast cell death, thereby deteriorating croissant quality. Therefore, we suggest that the croissant dough freezing process should be conducted with an appropriate FR down to a suitable terminal temperature. Consequently, our results are helpful to understand how the freezing procedure affects ice crystal formation and yeast viability in the frozen dough matrix and our findings can be applied to enhance bread quality in the frozen dough industry.