Enhancing the stability of probiotics: Freeze-drying and encapsulation

Research output: ThesisDoctoral Thesis (compilation)

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This research dives into the intricate world of freeze-drying, an essential process in pharmaceutical and probiotic industries, to better understand the factors affecting probiotic stability during storage. The process of freeze-drying and the composition of freeze-dried products significantly affect the stability of probiotics, yet factors such as the material’s encapsulation properties remain relatively unexplored, demanding further research.
This thesis will explore the effects of lyoprotectants, freezing, annealing, and drying on the structure of freeze-dried products. It aims to provide a comprehensive understanding of how varying conditions influence structural characteristics and their correlation with the storage stability of probiotics. We will also explore the key differences between vial and pellet formulations, and discuss topics critical for ensuring stability during storage such as glass transition temperatures.
The investigation uses techniques such as scanning electron microscopy (SEM) and X-ray micro- computed tomography (μCT) to investigate the structural attributes of freeze-dried material. The thickness of the encapsulating material is the central focus, revealing its crucial role in protecting the probiotic cells. The findings indicates that a notably thicker material provides increased protection, enhancing probiotic storage stability.
Original languageEnglish
Awarding Institution
  • Division of Food and Pharma
  • Wahlgren, Marie, Supervisor
  • Bergenståhl, Björn, Supervisor
  • Fureby, Anna, Supervisor
  • Larsson, Emanuel, Supervisor
Thesis sponsors
Award date2024 Feb 2
Place of PublicationLund
ISBN (Print)978-91-8096-018-2
ISBN (electronic) 978-91-8096-019-9
Publication statusPublished - 2024 Jan 9

Bibliographical note

Defence details
Date: 2024-02-02
Time: 09:15
Place: Lecture Hall KC:A, Kemicentrum, Naturvetarvägen 14, Faculty of Engineering LTH, Lund University, Lund. The dissertation will be live streamed, but part of the premises is to be excluded from the live stream.
External reviewer(s)
Name: Först, Petra
Title: Prof.
Affiliation: Technical University of Munich, Germany.

Subject classification (UKÄ)

  • Medical and Health Sciences
  • Other Chemistry Topics

Free keywords

  • freeze-drying
  • lyophilization
  • L.ruteri
  • Probiotics
  • Lyoprotectant
  • Structure
  • Encapsulating material
  • Pore size
  • Material thickness
  • SEM
  • Tomography
  • Storage stability
  • Amorphous sugars
  • Glass transition temperature
  • DSC


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