- The Washington Times - Wednesday, July 11, 2007

What’s so hot about chilies? Many people think it’s the seeds, but this is not really so.

Chili pepper pods are fruits — actually, the seed-bearing ovaries of the plant. They contain capsaicinoid compounds that are heat-producing in the mouth, and these are synthesized by the surface cells of the chili.

The hot compounds accumulate in droplets and form pools that look like little rough spots or bumps just under the surface of the interior. So it is possible to greatly reduce the heat of a chili by scraping out this interior network, seeds and all, and rinsing the inside of the pod.

Scientists originally thought the seeds were the source of the heat for good reason. When you cut into a chili, the knife slices into a number of the pools where the hot compounds accumulate and splatters them all over the seeds and inside of the pod. The incorrect conclusion: The heat originates in the seeds.

For the cook, there are several ways to control the heat. If you cut a chili in half and put half in, say, a soup, it may not be that powerful. However, if you take that same half and mince it, freeing the capsaicinoid compounds, and put that minced chili into a soup, it may well send you through the ceiling.

When your mouth is on fire from chilies, what can you do to relieve the pain? Water is of little help. The fire from capsaicin compounds — which are colorless, odorless and tasteless yet powerful alkaloids — are not water soluble. Mercifully, they are soluble in oil and alcohol. Oil and alcohol are more soothing than water, but food scientists know that milk provides the best relief.

Dr. Robert Henkin of the Taste and Smell Clinic in Washington says that the casein found in dairy products is a phosphoprotein that acts like a detergent to strip the capsaicin from the nerve receptor binding sites in the mouth.

In 1989, John Riley, editor of the science journal Solanaceae, tested various remedies to remove the burn. He found:

{bullet} Rinse the mouth with water: 11 minutes until relief.

{bullet} Rinse the mouth with 1 tablespoon olive oil: 10 minutes until relief.

{bullet} Drink ½ cup heavy fruit syrup: 10 minutes until relief.

{bullet} Rinse the mouth with 1 tablespoon glycerin: 8 minutes until relief.

{bullet} Drink ½ cup milk, rinsing well: 7 minutes until relief.

In a 1990 study at the University of California at Davis, Christina Wu Nasrawi and Rose Marie Pangborn reported that a 10 percent sucrose solution at 68 degrees was just as effective as cold milk at 41 degrees.

This explains why some cooks add sugar to reduce the heat in an excessively hot dish. Another old solution is a little vinegar. I like to simmer jalapeno slices in ½ cup vinegar, 1 cup sugar and 2 cups water to reduce the heat and produce a mellow taste. The cooking liquid is a great flavoring agent, too, as illustrated by the recipe that follows.

The biological reason for the burn from chilies is that capsaicinoid compounds irritate the trigeminal cells, which are pain receptors that release substance P, a neuropeptide that relays pain to the brain. Regular consumption of chilies can confuse substance P and enable people to build up a tolerance to capsaicin so they can eat hotter and hotter food.

In addition to causing pain, capsaicin can be used as a painkiller. When capsaicin is applied to the skin, it triggers a release of substance P, but after this initial burst the nerve endings cease to produce substance P. This reduces or eliminates pain signals to the brain.

Capsaicin is the only compound known to block transmission of substance P to the brain. When the capsaicin treatment is concluded, substance P stores revert to normal.

Scientists used to think that capsaicin was one compound, but the fiery crystalline extract from chilies is actually five compounds that scientists refer to as capsaicinoids: capsaicin (69 percent), dihydrocapsaicin (22 percent), nordihydrocapsaicin (7 percent), homocapsaicin (1 percent) and homodihydrocapsaicin (1 percent).

In the 1980s, food scientists John Powers and Anna Krajewska, then of the University of Georgia, studied professional taste tester comments on the separate compounds. Nordihydrocapsaicin was described as the “least irritating” and “fruity, sweet, and spicy,” while homodihydrocapsaicin was described as “very irritating” with a “numbing burn” in the throat.

Chili pungency depends on the plant genetics and growing conditions. This includes not only soil composition and rainfall, but the amount of sunshine, the maturation at time of harvest and even night temperatures.

All of these factors can influence the amount of capsaicinoids formed in a chili. This explains why New Mexican pods ripening with day temperatures between 86 and 95 degrees have twice as many capsaicinoids as pods ripening between 59 and 72 degrees.

Different types of chilies vary greatly in how hot they are. In 1912, Wilbur L. Scoville, a pharmacologist with the Detroit drug company Parke-Davis, which was using capsaicin in a muscle salve, developed a way to evaluate pungency. This pungency from chilies now is measured in Scoville units.

Here is what was found with a few varieties:

{bullet} 100,000 to 500,000 pungency units: habanero, Scotch bonnet, South American chinense, African birdseye

{bullet} 15,000 to 30,000: de arbol, crushed red pepper flakes, habanero hot sauce

{bullet} 5,000 to 15,000: early jalapeno, aji Amarillo, Serrano, Tabasco sauce

{bullet} 2,500 to 5,000: TAM (developed at Texas A&M; University) mild jalapeno, mirasol, Cayenne Large Red Thick, Louisiana hot sauce

{bullet} 1,000 to 1,500: ancho, pasilla, Espanola, Old Bay Seasoning

{bullet} 100 to 500: NuMex R Naky (developed by Roy Nakayama), Mexibell, cherry, canned green chilies, Hungarian hot paprika

{bullet} 0 units: mild bells, pimiento, sweet banana and U.S. paprika

Capsaicin also has many nonfood uses. It appears, for example, in medicines, as pepper spray for defense purposes and even as a treatment for squirrel-proofing bird feeders.

For the spicy grilled chicken strips that follow, chicken breast pieces are marinated in a low-fat bell pepper and jalapeno sauce that is as brilliant in taste as it is bright red in color.

The chicken is then grilled and served on a bed of greens. Some of the bell pepper and jalapeno sauce is reserved for dipping. Since sugar slows or prevents softening of fruits and vegetables, the bell peppers are simmered in water before sugar is added. The heat of the jalapenos is tamed by simmering in this sugar-vinegar water.

Candied ginger and lemon zest add flavor components, and a small amount of oil and dry sherry dissolve and release fat-soluble flavor components to enhance the taste.

Spicy grilled chicken strips

4 red bell peppers, cored, seeded and chopped

4 medium shallots

Water

6 medium (about 2 to 2½ inches) red jalapenos, split lengthwise and seeded (see note)

½ cup sugar

1/4 cup white vinegar

4 slices candied ginger, coarsely chopped

Grated zest of 1 lemon

½ teaspoon ground cumin

1 teaspoon ground coriander

1 to 2 teaspoons salt

2 tablespoon sesame oil

1 tablespoon dry sherry

6 skinless and boneless chicken breast halves, cut in half horizontally

3/4 pound watercress or blanched kale for garnish, optional

Simmer bell pepper and shallot in a heavy saucepan in just enough water to cover (probably 1 to 1½ cups). Simmer about 10 minutes until bell pepper softens. Stir in jalapeno, sugar and vinegar. Simmer mixture over low heat for 5 to 10 minutes. With a slotted spoon or strainer, transfer bell pepper and shallot to blender or food processor, reserving liquid.

Puree bell pepper and shallot along with candied ginger, lemon zest and 1 to 2 tablespoons of sugar-vinegar liquid. Puree until smooth. Add cumin, coriander, salt to taste, sesame oil and sherry, and blend. Thin with a little sugar-vinegar liquid to desired consistency.

Cut chicken breasts at an angle across the grain into ½-inch strips and marinate in 1/3 of the bell pepper sauce for at least 1 hour. Refrigerate remaining sauce to be used for dipping. (Marinade that has been exposed to raw chicken should be discarded.)

Grill chicken briefly until lightly browned and cooked through. Do not overcook.

To cook without a grill, spray a cooling rack with nonstick cooking spray. Cover a baking sheet with foil, place rack on sheet and chicken on rack. Place under preheated broiler, 4 inches from flame and broil 2 minutes.

Pour about 2 to 3 tablespoons of the dipping sauce into a small bowl and use it to baste the chicken. Broil 2 minutes more, or until chicken is cooked through but still moist and tender. Do not overcook.

Line a platter with watercress or blanched kale, if desired. Arrange chicken on platter with a small dish of dipping sauce in the center. Spoon some of the reserved sauce over the chicken. Serve hot, cold or at room temperature.

Note: If you want more heat, leave part of the white pithy veins in the jalapenos. (Wear gloves to handle them.) Also, if red jalapenos are not available, use green and leave the seeds in to give more flavor to the sugar-vinegar water, then remove the green jalapenos and discard. Just use the flavored water and the red bell peppers to maintain the red color.

Food scientist Shirley O. Corriher is author of “CookWise: The Hows and Whys of Successful Cooking” (William Morrow).

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