You are cordially invited to the defence of the doctoral thesis of Ing. Jan Staš titled “In vitro growth-inhibitory effect of plant-derived products against beverage-spoiling microorganisms” (Department of Sustainable Technologies, Tropical Agrobiology and Bioresource Management programme).
The defence will take place on 9 September 2025 at 10:00 AM in meeting room No. 313 (FTZ building).
About the Research
We all enjoy a glass of fresh orange or apple juice — but behind the scenes, tiny acid-loving yeasts can cause spoilage long before the “best before” date. Traditionally, this problem has been managed with synthetic preservatives. However, with more and more consumers looking for natural “clean label” products, the food industry faces a challenge: how to keep juice fresh without artificial additives.
This research tackled the problem by creating a new laboratory method that tests natural antimicrobial compounds directly in real juice, not just in artificial lab media. Using this approach, we identified plant-based substances that can fight spoilage yeasts effectively. Feel free to read more about the newly developed method here.
Besides this new method, our team of researchers also adapted the MTT colourimetric viability assay for use in opaque juice matrices, enabling quick, sensitive read-outs of yeast inhibition where standard turbidity methods fail.
Other highlights of the research:
- Pterostilbene, found in plants like blueberries, showed outstanding antifungal performance.
- Essential oils from lemongrass and fingerroot were highly active and are already locally available in many tropical countries.
- Extracts from certain mangrove species did not prove to be promising low-cost options for tropical juice producers.
- An adapted MTT assay for juices was developed: a rapid, user-friendly read-out of yeast viability that works even in turbid, colored juices, supporting high-throughput screening.
The findings open new opportunities for developing natural, safe, and effective ways to keep juice fresh — and delicious — for longer.
We warmly invite faculty members, students, and the public to join this defence and explore how plant-based science could change the future of juice preservation
