Investigation of the impact of pre- and post- drying treatments on the physicochemical and functional properties of whey powders
Loading...
Files
Full Text E-thesis
Date
2025
Authors
Gordon, Emma Jane
Journal Title
Journal ISSN
Volume Title
Publisher
University College Cork
Published Version
Abstract
Whey powder is a widely utilised ingredient produced in large volumes by the dairy industry. It is a versatile ingredient used in many products including animal feed, soups, bakery, confectionary, powder beverages, snack seasonings and dairy products.
Physicochemical and functional properties of whey powder are key in determining the processability, handling, storage, use and overall quality of the ingredient. Various unit operations and process technology interventions can be implemented to modify these properties. Thus, creating innovative powders that are tailored and optimised for particular end use application. These processes can be applied not only on the finished powder, but also to the wet feed prior to drying. The objectives of the work reported in this thesis were to investigate the impact of selected pre- and post-drying treatments on the physicochemical and functional properties of whey powder at three different points throughout the year, to take account for seasonality.
The first study (Chapter 2) explored the impact of in-line shearing of precrystallised whey concentrate on physicochemical and rehydration properties of the resultant powder. The results demonstrated that shearing whey concentrate prior to drying reduced the resultant powder particle size, along with significantly altering the powder colour, particle morphology, powder density, and viscosity of reconstituted whey powder. The shearing process had no effect on the flowability or rehydration properties of the powder.
Chapter 3 investigated the impact of altering the particle size post-drying on the physicochemical and functional properties of whey powder. The whey powder was agglomerated by coating the particles in a whey solution, while the powder was fluidised using a pilot-scale fluid bed dryer. The results showed that the agglomeration process, caused an increase in particle size, with concomitant effects on particle morphology, colour, density, flowability and protein content.
In addition to agglomeration, the whey powder was also milled to two different extents, producing two whey powders with reduced particle size. The milled powder’s colour, morphology, shape, density, flowability, and levels of protein denaturation were all altered as a result. In addition, the performance of the agglomerated and milled powders was also analysed in a simulated beverage and snack seasoning application systems.
The results from these two experimental studies demonstrate that, by shearing the crystallised concentrate pre-drying, the particle size of the resultant powder can be reduced, while the physicochemical and rehydration properties are not impacted as severely as they are for post-drying treatments (Chapter 3). The findings from this study will allow dairy researchers and processors to deepen their scientific understanding of the impact of pre- and post- drying treatments on the physical and functional properties of whey powder. This will enable the production of whey powders with physical and bulk handling properties optimised for selected applications.
Description
Keywords
Sweet whey powder , Particle size distribution , Spray drying , Rehydration properties , Physicochemical properties
Citation
Gordon, E. J. 2025. Investigation of the impact of pre- and post- drying treatments on the physicochemical and functional properties of whey powders. MRes Thesis, University College Cork.