Spray-dried egg white is commonly used as a food ingredient for its foaming and gelling properties. However, these properties are
obtained thanks to dry-heating of egg white powder, which is necessary to offset the harmful effects of spray-drying process on egg white
functionality. The purpose of the present work is to identify the processing steps responsible for the damages to egg white functional
properties, and to understand the mechanisms that occur in order to limit these effects and to reduce dry-heating time. Two trials were
performed and the measurements of egg white protein conformation and gel firmness were significantly different from one trial to
another, thus emphasizing great variations in raw material characteristics. In spite of this trial effect, processing steps significantly modified
egg white foaming properties. The most critical step was the spray-drying one that strongly damaged foaming properties. During
this step, heat transfers and air–product interface area rather than shear rates were responsible for these changes. Then, it was the pumping
and filtering steps that had also a considerable effect, due to the generation of shear rates and stainless steel–product interfaces,
responsible for foaming property damages. On the other hand, concentration and desugarization steps had an interesting improving
effect on egg white foaming properties.
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