‘Seeing’ the flavour of foods

When it comes to food, the eyes have it, scientists say. Speaking at the 245th National Meeting & Exposition of the American Chemical Society (ACS), Terry E Acree, PhD, from Cornell University, described how people sometimes ‘see’ flavours in foods and beverages before actually tasting them.

“There have been important new insights into how people perceive food flavours,” said Acree. “Years ago, taste was a table with two legs - taste and odour. Now we are beginning to understand that flavour depends on parts of the brain that involve taste, odour, touch and vision. The sum total of these signals, plus our emotions and past experiences, result in perception of flavours, and determine whether we like or dislike specific foods.”

The eyes play such a powerful role in taste, Acree says, that they can trump the tongue and the nose. Sauvignon blanc wine, for instance, gets its flavour from natural chemicals, including those with the flavour of banana, passionfruit, bell pepper and boxwood. But when served, a glass of sauvignon blanc tinted to the deep red of a merlot or cabernet sauvignon, people taste the natural chemicals that give rise to the flavours of those wine.

The sense of smell, likewise, can trump the tastebuds in determining how things taste, Acree said. Psychologists have conducted studies in which volunteers were asked to smell caramel, strawberry or other sweet foods and then take a sip of plain water. The participants reported that the water tasted sweet. But after smelling bread, meat, fish or other non-sweet foods, participants reported that the water did not taste sweet.

While the appearance of foods probably is important, other factors can override it. Hashes, chilies, stews and cooked sausages have an unpleasant look, like vomit or faeces, Acree said. However, people savour these dishes based on the memory of eating and enjoying them in the past. The human desire for novelty and new experiences also is a factor in the human tendency to ignore what the eyes may be tasting and listening to the tongue and nose, he added.

Acree said that understanding the effects of interactions between smell, vision and taste, as well as other odourants, will open the door to developing healthful foods that look and smell more appealing to fussy children or adults.