PhD defence by Ipek Altay

Principal supervisor

• Assoc. Prof. Mohammad Amin Mohammadifar

Co-supervisor

• Prof. Jens J. Sloth

Examiners

• Prof. Charlotte Jacobsen, DTU National Food Institute
• Prof. Lilia Ahrné, University of Copenhagen
• Prof. Meral Kiliç Akyilmaz, Istanbul Technical University

Chairperson at defence

• Assoc. Prof. Timothy John Hobley, DTU National Food Institute

Resume
Cheese powder is an extensively utilized ingredient found in a variety of food products, including snacks, bakery items, dressings, and soups. Its production traditionally involves spray drying a stable cheese emulsion, achieved through the incorporation of citrate or phosphate-based emulsifying salts. These salts play a crucial role in modifying the physical and chemical properties of milk proteins, particularly para-casein, by altering their interactions. This modulation affects the pH and enhances protein functionality, ensuring the formation of a stable emulsion suitable for spray drying. Despite their effectiveness, the increasing consumer demand for clean label products necessitates exploring alternative approaches to minimize or eliminate the use of these emulsifying salts.

To achieve this objective, it is essential to first understand how emulsifying salts interact within the casein system and assess the stability of model cheese emulsions without their use. Furthermore, it is crucial to explore the impact of conditions induced by emulsifying salts in cheese emulsions, such as calcium solubilization and pH adjustment, when these additives are absent.

Exploration of novel processing techniques can offer promising alternative for reducing the reliance on emulsifying salts. These techniques, such as ohmic heating, pulsed electric field application, and ultrasound treatment, have demonstrated efficacy in enhancing the solubilization and emulsification properties of milk protein systems through diverse mechanisms.

Through the analysis of the influence of emulsifying salts on the casein system and cheese emulsion, the impact of pH on cheese feed systems, and the application of novel processing techniques to improve protein availability, this research has the potential to pave the way for clean label cheese powder production with desirable functional properties.