Thermo-physical and thermo-mechanical assessment of partially baked bread during chilling and freezing process. Impact of selected enzymes on crumb contraction to prevent crust flaking

摘要

Several problems could arise from the storage of frozen part-baked breads under controlled freezing conditions for a prolonged period of time. One of the major quality problems of this product is crust flaking. The aim of this study was to study the thermo-physical changes provoked by freezing and frozen storage of partially baked bread (PB-bread) and to examine the effect of acid ascorbic, α-amy-lase, protease and hemicellulase on sub-zero breadcrumb properties by differential scanning calorimetry (DSC) and dynamic-mechanical analysis (DMA). The freezing and frozen storage provoked a retraction of part-baked bread (PB-bread) measured on a French stick; influenced water properties and increased the amylopectin retrogradation in PB-bread as measured by DSC; and modified the shrinking pattern of PB-breadcrumb. It seemed that the contraction stress that developed in the matrix during the freezing process of PB-bread was higher in frozen samples than in non-frozen samples due to the fact that they had a more rapid deformation during ice-crystallization.