Follow your nose to healthy eating
February 13, 2006 Edition 1
That fresh, grassy smell wafting up from the newly sliced tomato may be its way of saying, "I'm good for you".
Indeed, the odours from foods ranging from garlic and onions to ginger and strawberries may be nutritional signals that the human nose has learned to recognise.
"Studies of flavour preferences and aversions suggest that flavour perception may be linked to the nutritional or health value" of foods, researchers Stephen A Goff and Harry J Klee report in last week's issue of the journal Science.
However, they caution, cultivating vegetables for domestic use has not been kind to many of them, promoting qualities like colour, shape, yield and disease resistance instead of flavour and nutrition.
Flavour is complex and uniquely challenging to plant breeders, they note, and as a result has not been a high
priority.
Take the tomato, for instance.
Klee and Goff analysed two types of tomato, the wild cerasiforme and the commercially grown Flora-Duke.
Except for one chemical that also affects colour, the sugars, organic acids and volatile compounds associated with tomato flavour were reduced in the commercial product.
For example, one of the volatile compounds associated with the "tomato" or "grassy" flavour is called cis-3-Hexenal, which is also an indicator of fatty acids that are essential to the human diet. They found that the wild tomato contained more than three times the amount of that chemical than the cultivated version.
In addition to tomatoes, those chemicals are also important constituents of the flavours of apples, strawberries, bread, cheese, wine and beer, they reported.
Goff and Klee also noted that the scent compounds in many spices are associated with health properties.
"A preference for the flavours found in spices such as turmeric and ginger is believed to have developed due to the health benefit of less contaminated food," they conclude.
The odours of the compounds are of particular interest because they are a major factor in how taste is perceived.
The human tongue senses just five flavours - sweet, sour, salty, bitter and umami, sometimes called savoury - and scent provides considerable added information about a food. - Sapa-AP
