"This work constitutes a first step toward computer-aided product formulation by allowing calculation of retronasal aroma intensity as a function of transfer and volatility properties of aroma compounds in food matrices and anatomophysiological characteristics of consumers," wrote the researchers in the journal Chemical Senses.
The researchers, led by Ioan Cristian Trelea at AgroParisTech/INRA (Institut Nationale de la Recherche Agronomique, UMR782), based their model on the physiology of the swallowing process of three aroma compounds representing the strawberry flavour (ethyl acetate, ethyl butanoate, and ethyl hexanoate).
Three panellists were recruited to eat flavoured yoghurt and the aroma concentration was measured by mass spectrometry sampling air from their nasal cavities.
In the formulation of their mathematical model, the researchers carefully considered the various processes on flavour and aroma perception. The first step includes the mixing of air and the product during chewing, which releases volatile compounds. The second step involved swallowing, when breathing stops and an aroma-rich air is expelled. The process starts over again, except after the first mouthful, the mouth and throat are now covered in a thin product film that is permanently in contact with the airflow. This means there is now a continuous aroma release to the nose.
After factoring these, and other paramters, they present a detailed mathematical model that was verified by tests with the panelists.
The researchers state: "It is of a great interest to have a quantitative description of in vivo aroma release because:
1) it is a key step in understanding the role of the product (composition and structure) and of the consumer (physiological parameters and individual experience) in the perceived flavour,
2) it is essential in understanding the role of the oral mechanisms and processes in the flavour release, and
3) it could help to design food products taking physiological characteristics of individuals (young or elderly, healthy subjects, or with some clinical pathologies as dysphasia) into account."
Further research is planned by Trelea and co-workers, with future directions suggested to include measurements from a larger number of individuals to enhance reliability, using a higher sensitivity spectrometer to account for compounds at lower concentration and/or less-volatility, and considering additional factors like the effect of saliva on dilution.
"Model extension to liquid or solid foods would broaden its applicability to many sectors of food industry," they concluded.
Previously, scientists have used artificial noses, tongues and throats to mimic the way humans taste. Such devices are viewed as ways to reduce development costs by slicing out the panel of human tasters. This saves food and beverage makers both time and money, equating to a competitive turnaround to market.
Source: Chemical Senses
Published on-line ahead of print, 28 November 2007, doi:
"Mechanistic Mathematical Model for In Vivo Aroma Release during Eating of Semiliquid Foods"
Authors: I.C. Trelea, S. Atlan, I. Deleris, A. Saint-Eve, M. Marin, I. Souchon