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Kitchen Chemistry 101, Part 2: The how and why of taste and flavour


Published: 06/20/2012

by William Roebuck


You might think that adding taste to food involves little more than sprinkling on some salt and pepper. But there's much, much more to flavour than that.

Taste and flavour encompasses not only chemistry but biology and psychology as well. Chemistry is about the organic components of food, biology involves the receptive systems that allow us to experience these components, and psychology is our subjective perception of taste and aroma. We can only just skim the surface of these sciences but here are a few facts to whet your appetites.

Tasty tidbits to savour

* There are about 10,000 taste receptors located on the tongue, palate and throat.
* We taste four basic organic chemical qualities; sweet (sucrose), salt (sodium), sour (acid) and bitter (alkaloid).
* We taste sweet at the tip of the tongue, salt and sour on the sides and bitter at the very back of the tongue.
* Sugar has the effect of making sour, acidic foods more palatable and a bit of sugar in an overly salty dish will reduce the perception of the salt taste.
* The salty taste we experience when we add sodium chloride (table salt) comes from the sodium part of the molecule, not the chloride.
* Sodium, in moderation, can enhance the taste of acids and reduce the taste of bitter substances.
* Taste is our perception of the complex amalgamation of chemicals in our foods and is affected by the temperature, texture and aroma of the food.

* Most of what we call taste is really aroma, as our olfactory (smell) systems are 10,000 times more sensitive than our gustatory (taste) systems.

* The colour of food also plays a role in our perception of flavour and if colour and flavour are inconsistent, then we have trouble identifying the flavour (which makes one wonder about how well the new green ketchup will do).
* The taste sensation we call astringency is associated with a dry, puckery feeling in the mouth and is caused by the tannins in certain foods reacting with the protein in our saliva.
* The taste sensation we call pungency describes the hot, sharp and stinging qualities found in chili peppers, garlic and ginger.

* Capsaicin, an alkaloid found in chili peppers, has no taste of its own but rather stimulates pain receptors in the mouth and boosts body temperature and adrenaline levels.

* Flavours are created through cooking, fermenting or seasoning food with herbs and spices.
* Cooking food produces an infinite variety of flavours and the temperature and type of cooking play a big part, so that boiling, roasting or grilling the same food can result in very different flavours.
* Fermentation, another method of creating tastes, is the result of the action of bacteria or yeast on the sugars in food.
* Herbs are usually the leaves of aromatic plants and have low levels of the essential oils that give them their characteristic tastes.
* Spices are generally the seeds, flowers, fruit or bark of plants and contain high levels of essential oils and are therefore more powerful in the flavouring process than herbs.

Now that you know a little more about seasonings and flavours, the Home Digest kitchen offers three recipes that we think will take advantage of the chemistry of spices and flavours and delight the palate.

Pistou (Pesto)

This is the French variation on the more familiar Italian pesto. In this recipe the high-fat pine nuts are left out, but all the aromatic qualities of the basil, along with the pungent garlic, remain. This sauce will keep refrigerated for a couple of days and can be tossed with cooked pasta, spread on a toasted French baguette or used as topping on a hearty vegetable soup.

3 large garlic cloves, peeled
3 cups(packed) fresh basil leaves
6 Tbsp. olive oil
3/4 cup grated Parmesan cheese
pepper to taste

Using a food processor, chop garlic, add basil and continue processing until basil is finely chopped. With machine running slowly add oil. Add cheese and process to blend. Add pepper and transfer to bowl. Cover and refrigerate for later use or enjoy immediately.

There's the rub

A spicy rub is good way to season meat for the BBQ. While rubs give meat flavour, they don't tenderize, so we suggest that you use this recipe on pork or tender cuts of beef. You can also add your favourite BBQ sauce at the end of the cooking for even more flavour. This rub will cover 3 lb of meat (about six servings) and can easily be doubled.

1 Tbsp. ground cumin
1/2 Tbsp. chili powder
1/2 Tbsp. dry mustard
1/2 Tbsp. salt
1/2 tsp. cayenne pepper (more if you like it hotter)
1 tsp. cardamom
1 tsp. ground cinnamon

Mix all ingredients together in a bowl and rub mixture over both sides of the meat. Place meat on a pan, cover and refrigerate for three to four hours. If desired, add sauce just before meat is finished cooking.

Strawberries in wine

This simple dessert recipe combines sweet fruit and a little sugar with a dry red wine. The astringent qualities of the wine are mellowed by the addition of the sugar, resulting in a delicious marriage of tastes. This recipe makes six servings but can be doubled.

1/2 bottle of dry red wine
3 cups of fresh strawberries, washed, hulled and cut in half
1/4 cup sugar

Combine wine and sugar and stir until sugar is dissolved. Pour over strawberries, mix gently, cover and refrigerate three to six hours. Serve in stemmed glasses.

To learn more about kitchen chemistry, we recommend the informative and entertaining book "The Inquisitive Cook" by Anne Gardiner and Sue Wilson of British Columbia (Henry Holt, $19.95).


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