Detecting and eliminating off-odours in food is vital in the development of new products, but many of the most aroma-active compounds can be present at levels that make it difficult to implement widely-used analytical techniques such as purge-and-trap. We talk to food scientist Diana Owsienko, who has turned to Markes’ HiSorb and Centri technologies to extract key analytes more quickly from smaller amounts of sample. As a result, it’s now easier to run sensory and instrumental analyses on the same batch, for better correlation of results, all within a more streamlined, automated workflow.

Understanding the aroma of food

Consumer satisfaction with the food we eat depends on a variety of sensory characteristics, of which aroma makes a vital contribution. But the sensitivity of the human nose to individual compounds also makes understanding the origin of certain aromas a uniquely tough analytical challenge. One person who’s acutely aware of this is Diana Owsienko, who works within the Aroma Chemistry Group at RISE, Sweden’s government-funded network of research centres. The group is currently working on several collaborative research projects that involve developing new plant-based foods that are tasty, nutritious, and have an improved sustainability profile.

She explains the challenge they were facing: “One of our projects involves exploring alternative protein sources such as legumes. But legumes can produce a ‘beany’ odour, which can be  undesirable if it’s apparent in the final food product – so we were working to understand the compounds that give rise to it, and how to reduce their levels”.

Overcoming the limitations of existing methods

To investigate the causes of this off-odour, Owsienko and colleagues had been using purge-and-trap sampling. Gas-phase volatiles in the headspace above an aqueous protein-powder suspension were being collected on sorbent tubes, followed by thermal desorption and detection by GC–olfactometry and GC–MS. This combination of sensorial and instrumental detection techniques is commonplace in the field of food analysis, because it allows odours detected by the human nose to be matched to the chemical that gives rise to them.

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