Cryo-protective effect of ice-binding proteins produced by Pseudomonas fluorescens AQP671 on wholegrain wheat bread dough during freezing and frozen storage

Ice-binding proteins (IBPs) of cold-induced Pseudomonas fluorescens AQP671 were assessed for their potential as cryoprotective agents in frozen wholegrain wheat dough during freezing and 8 weeks of frozen storage. The protein solution exhibited significant ice-recrystallization inhibition activity at total protein concentrations of 0.1 g/L and above. The addition of IBPs improved the yeast survival rates in the dough post-freezing on average 7.8% compared to the untreated samples. Additionally, yeast survival rates were stable during 8 weeks of frozen storage in samples that had at least 5% (0.09 g/kg) of the total dough weight supplemented with the protein solution. As a result, the rising capacity of the dough was improved by the addition of ice-binding proteins, correlating to their concentration in the dough. Additionally, the freeze tolerance of the starch granules was maintained for at least 6 weeks for all of the IBP-treated samples. Furthermore, the ice-binding proteins had a positive effect on the strength of the dough after thawing, indicating less damage to the gluten structure and improved the overall texture and sensory parameters of the final bread product. • P. fluorescens AQP671 IBPs have high ice recrystallization inhibition activity. • IBPs can protect the yeast cells during freeze-thaw cycles. • IBPs decrease the degradation of starch granules during frozen storage. • The supplementation of IBPs may help maintain the texture and sensory attributes of bread made from frozen dough.