How Genes Affect Flavour

Armed with new genomic knowledge related to taste sensations, food manufacturers can naturally capture the essence of good-tasting food from the seas, mountains and fields. Barbara Anan Kogan, OD, reports

Gustation—the sensation of taste—is synonymous with flavour and represents a combination of taste, smell and texture. Taste bud receptors, 10,000 of which are primarily on the tongue, can perceive and differentiate food, pharmaceuticals and nutraceuticals as sweet, sour, salty, bitter or savoury. When a substance evokes a taste sensation, it must dissolve in the fluids that bathe the tongue and interact with the receptor cells of the taste buds.

Flavour influences what we like to eat—and what we eat is a large risk factor for disease. Flavour components develop as foods ripen, age, ferment, boil and grill when large proteins and carbohydrates break down into small flavour molecules. The release of these molecules as we eat influences our flavour perception and cravings, especially for fat. Healthier foods that have lower fat change the way flavours are released, and subsequently taste perception can be less desirable.

Food manufacturers can use fat substitutes to trick the taste receptors into mimicking a 'full mouth' feel, while simultaneously not delivering any of the fat calories. In one instance, casein added at a low percentage can make skim milk taste like whole milk.

To make healthier foods taste better, food manufacturers are developing natural and 'indulgent' mock flavours—meat flavours sans meat or bakery flavours such as hazelnut and raspberry cheesecake. Additionally, each flavour must be allergen-free.

Using The Gene Pool
Researchers at the National Institutes of Health's (NIH) National Institute on Deafness and Other Communication Disorders, which studies normal and disordered processes of taste, recently identified the gene that predisposes individuals to bitter tastes. The gene for this trait on chromosome-7 exists in five different forms throughout the world, varying from severe deficiency to a full taste receptor complex. Region 7q contains a single gene that encodes for the TAS2R38 bitter taste receptor family (the 38th human bitter taste receptor gene found).

In 1997, NIH researchers found that the active ingredient in hot peppers, capsaicin, binds to a specific receptor that sits on the surface of a neuron. The NIH's National Institute of General Medical Sciences Research on Transient Receptor Potential (TRP) ion channels to identify how individuals taste hot and minty cool sensations is listed as one of 2002's top-10 scientific achievements by the American Association for the Advancement of Science's journal, Science.

Here, researchers identified several proteins embedded in the surfaces of cells that respond to both chemical flavours and change in temperatures. The molecular basis for the vanilloid compound capsaicin that was identified is part of the trigeminal sensory neurons in the fifth of 12 cranial nerves. This same nerve can also elicit cooling sensations. This information will aid food manufacturers that develop functional foods with a way of finding new synthetic taste compounds for food additives using a combination of these newly discovered sensory taste and olfactory neurons.

Less Filling, Tastes Great
Food manufacturers want to preserve flavour when they add vitamins, minerals and fibre to their products. Researchers found that 4,000 children and teens who drank milk flavoured with vanilla, chocolate or strawberry consumed more of the daily recommended intake of calcium (though they also added more sugar).

Manufacturers are also now using more natural flavours, as opposed to processed ones, to broaden flavour appeal to younger purchasers. Fruit flavours, for example, are being used for the beverage industry, specifically in dairy products and sodas. Cereal manufacturers are making fibre and taste compatible without highly refined sugar or artificial anything. A toothpaste manufacturer also introduced its herbal version with lemon extract, natural mint and eucalyptus. The key, ironically enough, is to make natural flavours every bit as appealing as the synthetic ones they've grown up tasting.

Barbara Anan Kogan, OD, has been a clinical researcher in the area of CVD and is a nutritionally oriented optometrist in Washington, DC.

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