The release of aroma from a starch-containing food is dictated by interactions of the volatile compound with the carbohydrate, suggests new research from France.
Published in the Journal of Food Science, the research adds to our understanding of how food formulations impact the release of aromas, a key criterion to consumer acceptance of a product.
How consumers sense food is crucial knowledge for a food industry constantly organising the building blocks of new food formulations.
The new study was performed by researchers at Flaveur Vision Comportement de Consommateru (FLAVIC), a joint research group combining Etablissement National d'Enseignement Supérieur Agronomique de Dijon (ENESAD) and Institut National de la Recherche Agronomique (INRA).
The researchers, led by Nathalie Cayot, investigated the role of food structure and texture on the release of model aromas, linalool and isoamyl acetate. These aromas were selected because linalool is known to form complexes with amylase in starch, while isoamyl acetate does not form complexes, explained the researchers.
Cornstarch dispersions were prepared with similar starch concentrations but differing structures, and the aroma compounds added. Their release was measured under stirring at 20 or 32 degrees Celsius by discrete sampling of the headspace.
Cayot and co-workers report that, as they had expected, the release of linalool appeared to be controlled by interactions with starch, noting that the strength of the bonds between starch and aroma increased when extra-sheared starch was used.
A link between temperature and binding strength was also observed, stated the researchers, with increasing temperature linked to lower bond strengths.
"This is in accordance with the fact that the formation of complexes between linalool and starch occurred during the cooling of the starch dispersion and were thus more stable at 20 degrees C than at 32 degrees C," they wrote.
On the other hand, the release of isoamyl acetate changed according to the structure of the starch dispersion, with the aroma compound reportedly "less "mobile" in the extra-sheared matrix than in the non-sheared matrix."
A similar observation as for linalool was reported with regards to temperature, with greater release observed for higher temperatures.
Early last year, researchers from Agri-Food Canada reported in the Journal of Food Science (March 2007, Volume 72, Issue 2) that flavour and aroma release from emulsions was dependent on the oil concentration of the emulsion.
"Flavour release from food depends on the composition and the microstructure of the matrix, the properties of aroma compounds (molecular weight, solubility, hydrophobicity, and so on), and their interactions with other food components. Proteins, lipids, and polysaccharides have been shown to affect the rate of flavour release because of their ability to bind, solubilise, or retard the mass transfer of flavours," explained Agri-Food Canada's Helene Giroux.
Flavour, defined as combined sense of taste and odour, is a key driver in the €3.2 trillion global food industry.
Source: Journal of Food Science
Published online ahead of print, OnlineEarly Articles, doi:10.1111/j.1750-3841.2007.00645.x
"Influence of the Structure of Cornstarch Dispersions on Kinetics of Aroma Release"
Authors: C. Lafarge, M.-H. Bard, A. Breuvart, J.-L. Doublier, N. Cayot