During her PhD studies, Lotte Juul Knudsen investigated the storage stability of lactose-hydrolysed UHT milk. To produce lactase-hydrolysed UHT milk, a lactase enzyme is added to break down lactose (milk sugar) to glucose and galactose, which can be absorbed through the intestine. Producing long-life lactose-hydrolysed UHT milk is a challenge for the dairy industry as chemical and physical changes in the milk can occur during storage. These changes can lead to deterioration of the product and decreased shelf life. Lotte Juul Knudsen studied the development of Maillard reactions, proteolysis and protein aggregation of differently processed milk treated with three different types of lactase enzymes during a one-year storage period. The study contributes to a better understanding of the interrelations between these chemical and physical changes and in addition shows that lactase enzymes of higher purity can aid limiting certain chemical reactions during storage of lactose hydrolysed milk.

The PhD study was completed at Department of Food Science, Faculty of Technical Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Tuesday, 27 August 2024 at 13:00
Place: Building 5910, room 116, Department of Food Science, Aarhus University, Agro Food Park 48, 8200 Aarhus N
Title of PhD thesis: Storage stability of lactose-hydrolysed UHT milk in relation to proteolysis, Maillard reactions and aggregation
Contact information: Lotte Juul Knudsen, e-mail: Ljk@food.au.dk, tel.: +45 21498829
Members of the assessment committee:

Professor Marianne Nissen Lund, Department of Food Science, University of Copenhagen, Denmark

Research Officer Noel McCarthy, Food Chemistry and Technology Department, Teagasc Food Research Centre, Ireland

Professor Marianne Hammershøj (chair), Department of Food Science, Aarhus University, Denmark

Main supervisor:

Professor Lotte Bach Larsen, Department of Food Science, Aarhus University, Denmark

Co-supervisors:

Research scientist Søren Drud-Heydary Nielsen, Arla Foods Ingredients, Nr Vium, Denmark

Former tenure track assistant professor, Department of Food Science, Aarhus University, Denmark

Professor Daniel E. Otzen, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark

Senior scientist Valentin Rauh, Arla Innovation Centre, Arla Foods amba, Agro Food Park, Denmark

Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Technical Sciences/GSTS,

Jens Baggesens Vej 53, building 5221, 8200 Aarhus N.