While foods contain many thousands of volatile chemicals, only around 230 of them play a role in how we perceive the odour of a food, say researchers.
New research investigating the chemistry of how we are able recognise the characteristic odours of foods like strawberries, coffee, barbecued meat or boiled potatoes by smell alone has shown that there are around 230 key substances that can determine the odour of a food - with a maximum of around 40 number of these odours present in any one foodstuff.
Writing in Angewandte Chemie, researchers from Technische Universität München (TUM) and the German Research Center for Food Chemistry (DFA) carried out a meta-analysis on the odorant patterns of 227 foods.
Led by senior author Professor Peter Schieberle, the team were surprised to find that the almost unlimited variety of food smells is based on 230 key odorants. In addition, each foodstuff has its own odour code comprised of a core group of between just three and 40 of the 230 key odorants – in specific concentrations.
These small groups of odorous substances are what give all kinds of foods – from pineapple to wine to roast meat – their unmistakable aromas, said the team.
"So for example, the smell of cultured butter is encoded by a combination of just 3 key molecules, but fresh strawberries have 12," explains Schieberle - who added that Cognac is the most complex of all those tested, with the smell of the popular brandy is attributable to 36 key molecules.
The German team said their findings are important for the basic understanding of how we perceive foods, but also has great importance to industry who can use such findings to re-create more authentic flavours and odours.
"This perspective gives insight into nature’s chemical signatures of smell, provides the chemical odour codes of more than 220 food samples, and beyond addresses industrial implications for producing recombinants that fully reconstruct the natural odour signatures for use in flavours and fragrances, fully immersive interactive virtual environments, or humanoid bioelectronic noses," they wrote.
Optimising odours in food production
So far, scientists have identified 42 receptors that respond to food odors – with the majority binding multiple odour molecules, noted the team.
"By mapping the odorous substances of the 230 currently known key odours, scientists can test which receptor combinations are 'reserved' for food odours," explained Professor Thomas Hoffman, who also worked on the research. "This will help us explain the biological relevance of odours in even greater detail."
The mapping of odour codes also opens up new possibilities for biotechnology applications, they said.
For example, knowing more about the odour codes of crop plants and fruits at molecular level can be useful to breeders. In the past, increasing yield and ground coverage had a much higher priority than sensory quality.
The findings also lay the scientific groundwork for the next generation of aroma products, which use the potential of optimized biosynthetic pathways in plants for industrial-scale production of high-quality food odorants, they said.
Source: Angewandte Chemie International Edition
Volume 53, Issue 28, pages 7124–7143, July 7, 2014, doi: 10.1002/anie.201309508
"Nature’s Chemical Signatures in Human Olfaction: A Foodborne Perspective for Future Biotechnology"
Authors: Andreas Dunkel, Dr. Martin Steinhaus, et al