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

Abstract

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-amylase, 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.