Following the recent Coffee Club organised by members of the Deutsche Gesellschaft für Sensorik (DGSens), we had the opportunity to further discuss the topic of sensory analysis of recycled plastics with Zinaida Catruc, researcher at the Fraunhofer Institute for Process Engineering and Packaging, who presented the session, and Hannah Jilani, co-organiser of the event and researcher at the University of Bremen.
The Coffee Club with Germany initiated an interesting discussion on the sensory challenges associated with recycled materials, a topic that is becoming increasingly important as recycled plastics are more widely used in food and consumer packaging. To explore the topic further, we asked Zinaida a few additional questions about her research and the current challenges in the field.
One of the main difficulties when evaluating recycled plastics is the assessment of odour intensity. While this may seem relatively straightforward at first, comparing sensory profiles between recycled materials is actually quite complex. Different samples can present very different sensory defects, such as “burned”, “rubber-like” or chemical notes, making direct comparisons difficult. Even plastics originating from the same raw material can develop distinct sensory properties depending on their previous use and recycling conditions.
One particularly interesting aspect of this work is the combination of sensory science with analytical chemistry and data analysis. Through interdisciplinary collaborations, Zinaida and her colleagues have been able to correlate human sensory perception with analytical measurements obtained from both virgin and recycled plastics. This approach has led to the development of predictive tools for odour properties, representing an important step toward instrumental flavour monitoring in recycled materials.
The discussion also highlighted the importance of the material’s history itself. According to Zinaida, the main factors influencing off-flavours in recycled plastics are related both to the previous use of the packaging and to the recycling process applied afterward. Residual compounds, contamination and thermal degradation can all contribute to the formation of undesirable sensory notes.
Beyond identifying these sensory defects, the objective of this research is also highly practical: improving the quality and acceptance of recycled packaging. By integrating sensory science into recycling research, this work provides engineers and manufacturers with valuable information about the effectiveness of recycling methodologies and the most suitable reapplications for recycled plastics.
Looking ahead, one of the next major challenges will be to collect larger datasets covering different recycled materials and odour profiles. Expanding this knowledge base should help better understand how processing conditions influence odour formation and ultimately contribute to reducing the sensory impact of recycled plastics.
Useful links :
Zinaida Catruc
https://www.linkedin.com/in/zinaida-catruc-2a65a5263
Hannah Jilani