Excess consumption of salt (sodium chloride) has been linked to an increased risk of high blood pressure, which can lead to cardiovascular events like stroke. The majority of salt consumed is not added to food in the home, but is ‘hidden’ in manufactured food products.
The food industry is under considerable pressure to reduce the salt content of its wares, but it doing so it must still deliver products that have an acceptable taste.
Researchers from INRA in Dijon, France, working in cooperation with Unilever Food and Health Research Institute, set out to investigate the interaction between odour and saltiness.
“The overall perception of flavour is considered as an integration of simultaneous sensory perceptions including taste and colour,” they wrote in a study which has been accepted for publication in the journal Food Quality and Preference.
The results indicate that when a consumer expects a certain flavour, the perception of saltiness is enhanced. The change in taste perception is thought to come about through odour.
The study consisted of two experiments. In the first, a panel of 81 consumers was asked to say what taste that they would expect from 86 different food labels.
The researchers presented them with labels that evoked the idea of saltiness in their name, such as anchovy and bacon, and noted differences between the expected saltiness and actual salt content.
In the second experiment, the researchers picked commercially available aromas that corresponded to 15 of the salt-associated labels. These were sardine, bacon, anchovy, peanuts, tuna, Roquefort cheese, ham, chicken, Compte cheese, soy sauce, sotolon, concentrated cheese, tomato, goat’s cheese, and carrot. (The data from four of them were discounted, however, as they were found to have a taste). Water was used as a reference.
The aromas were put into aqueous solutions, with or without added sodium chloride;
A panel of 51 consumers was asked to rate the sensory attributes by smelling the solution (orthonasally) and tasting it in the mouth (retronasally).
The research team observed that the effect of odours on enhancing saltiness was especially pronounced in simple water solutions that contained just a small amount of salt.
“Our data revealed saltiness differences between tasteless aroma solutions evaluated orthonasally or retronasally,” they said. “We especially found the saltiness score to be higher when the odour was perceived orthonasally. Once in the mouth, most of the tested aroma solutions were not perceived as significantly more salty than water.”
Implications for other tastes?
The researchers concluded that odour-induced taste enhancement could also be used to compensate for the taste of fat and sugar content in foods formulated along healthier lines. For instance, butter or cream odour could enhance the perception of creaminess.
But they add a caveat: “Sugar and fat are known to highly influence texture and mouthfeel of food products. Therefore, all sensory aspects of food products reduced in salt, sugar and fat need to be addressed, to reformulate food products that would be acceptable to consumers.”
Food Quality and Preference (Elsevier). Published online ahead of print
“Odour-taste interactions: A way to enhance saltiness in low salt content solutions”
Authors: G Lawrence, C Salles, C Septier, J Busch, T Thomas-Danguin.