The effects of freezing and thawing on the structure, rheology and associated physical properties of galactomannan solutions for food applications

This PhD research opportunity focuses on developing a detailed understanding of how galactomannans are affected by freezing and subsequent thawing, both in aqueous solution and in the presence of sugars. Foods are complex multi-phase structures characterized by wide ranges of length and time scales. For most food products, the aim is to increase sustainability, health and ethical credentials without compromising on customer experience or cost. Galactomannans, such as locust bean or guar gums, are important food polymers due to their strong thickening, stabilizing, and gel-forming properties. As a solution freezes, polymer/sugar are expelled from the growing micro-crystals resulting in strong changes in local structure and rheology, and in effects such as cryo-gelation. The project will use advanced physical characterisation and analysis approaches including combining active (magnetic) and passive (thermal) particle tracking and Differential Dynamic Microscopy analysis, fluorescence lifetime microscopy of molecular rotor dyes, bulk rheology, light scattering and electron microscopy. The project addresses the key societal and industrial question of developing more sustainable and healthier food matrices, strongly linking to soft matter science capabilities. This research is in collaboration with the Magnum Ice Cream Company and links to EPSRC research areas including biophysics and soft matter physics, biological chemistry, complex fluids and rheology, and polymer materials. The application of fundamental soft matter science to foods strengthens interdisciplinary research and establishes leading capabilities in soft matter science. This is a fully funded 3.5 year PhD position through the EPSRC Faculty Doctoral Landscape Award, providing full academic fees and a tax-free maintenance grant at the standard UKRI rate (£20,780 in academic session 2025/26). Training and support will also be provided.