On Food And Cooking Part 49

Phenolics

Eugenol

Clove Clove

Cinnamaldehyde

Cinnamon and ca.s.sia Cinnamon and ca.s.sia

Anethole

Anise Anise

Vanillin

Vanilla Vanilla

Thymol

Thyme Thyme

Carvacrol

Oregano Oregano

Estragole

Tarragon Tarragon

The Flavor Components in Common Herbs The Flavor Components in Common HerbsThis chart and the chart opposite are a guide to experiencing flavorings from plants as the flavor mixtures they truly are. The charts identify some of the important flavor notes in individual herbs and spices, both by general sensory quality and by the names of the chemicals that contribute them. This information can help us perceive more in the flavor of a given herb or spice, and understand its affinities for other ingredients.The lists of flavor qualities and chemicals are selective, and the groupings informal. The "light" category comprises mainly terpene compounds, the "warm" and "penetrating" categories mainly phenolic compounds. "Distinctive" compounds are those that are found almost exclusively in one herb or spice and contribute much of its character.

The Flavor Components in Common Spices Flavor Families: Pungent Chemicals There is a major exception to the rule that herbs and spices provide aroma. The two most popular spices in the world are chillis and black pepper. They and a handful of other spices - ginger, mustard, horseradish, wasabi - are especially valued for a quality often called hotness, but best called pungency pungency: neither a taste nor a smell, but a general feeling of irritation that verges on pain. Pungency is caused by two general groups of chemicals. One group, the thiocyanates, are formed in mustard plants and their relatives, horseradish and wasabi, when the plant cells are damaged. Most thiocyanates are small, light, water-repelling molecules - a dozen or two atoms - that readily escape from the food into the air in our mouth, and up our nasal pa.s.sages. In both the mouth and nose they stimulate nerve endings that then send a pain message to the brain. The second group of pungent chemicals, the alkyl-amides, are found preformed in a number of unrelated plants, including the chilli, black pepper, ginger, and Sichuan pepper. These molecules are larger and heavier - 40 or 50 atoms - and therefore less p.r.o.ne to escape the food and get up our nose; they mostly affect the mouth. And their action turns out to be very specific. They bind to particular receptors on certain sensory nerves and essentially cause those nerves to become hypersensitive to ordinary sensations - and thus to register the sensation of irritation or pain. The mustard thiocyanates appear to act in a similar way in the mouth and nose.

Why Pain Can Be Pleasurable Why should irritating spices be our favorites? Psychologist Paul Rozin has proposed a couple of different explanations. Perhaps spicy foods are the edible equivalent of riding a rollercoaster or jumping into Lake Michigan in January, an example of "constrained risk" that sets off uncomfortable warning signals in the body. But since the situations are not truly dangerous, we can ignore the normal meaning of these sensations and savor the vertigo, shock, and pain for their own sakes. The sensation of pain may also cause the brain to release natural pain-relieving body chemicals that leave a pleasant glow when the burning fades.

Stimulation and Sensitizing We may also enjoy spicy food because irritation adds a new dimension to the experience of eating. Recent research has found that, at least in the case of the pepper and chilli irritants, there's a lot more to pungency than a simple burn. These compounds induce a temporary inflammation in the mouth, transforming it into an organ that is more "tender," more sensitive to other sensations. Those heightened sensations include touch, temperature, and the irritating aspects of various other ingredients, including salt, acids, carbonation (which becomes carbonic acid), and alcohol. It's the pepper that makes Chinese hot and sour soup, which is hot and acidic and salty, into such an intense experience. A few mouthfuls and we become conscious of simply breathing: our mouth becomes so sensitive that exhaling body-temperature air feels like a textured hot bath, inhaling room-temperature air like a refreshingly cool breeze. We may also enjoy spicy food because irritation adds a new dimension to the experience of eating. Recent research has found that, at least in the case of the pepper and chilli irritants, there's a lot more to pungency than a simple burn. These compounds induce a temporary inflammation in the mouth, transforming it into an organ that is more "tender," more sensitive to other sensations. Those heightened sensations include touch, temperature, and the irritating aspects of various other ingredients, including salt, acids, carbonation (which becomes carbonic acid), and alcohol. It's the pepper that makes Chinese hot and sour soup, which is hot and acidic and salty, into such an intense experience. A few mouthfuls and we become conscious of simply breathing: our mouth becomes so sensitive that exhaling body-temperature air feels like a textured hot bath, inhaling room-temperature air like a refreshingly cool breeze.

Examples of pungent flavor compounds. capsaicin capsaicin Strong pungency actually diminishes our sensitivity to true tastes - to sweetness, tartness, saltiness, bitterness - and to aroma, in part because it usurps some of the attention our brains would normally pay to these other sensations. Our sensitivity to pungent flavorings also declines with exposure to it, and that desensitization lasts for 24 days. This is part of the reason that regular chilli-eaters can tolerate hotter dishes than people who enjoy pungent food only occasionally.

Herbs, Spices, and Health Herbs and Spices as General Medicinals The idea that herbs and spices have medicinal value is an ancient one, and grounded in fact: plants are virtuosos of biochemical invention, and have been the original source of many important drugs (aspirin, digitalis, quinine, taxol are just a few). The health effects of plant foods in general are discussed above, p. 253. Herbs and spices, with their specialization in phenolic and terpene compounds, are notable for three broadly helpful tendencies. Phenolic compounds often have antioxidant activity; oregano, bay leaf, dill, rosemary, and turmeric are among the most effective. Antioxidants are useful both in the body, to prevent damage to DNA, cholesterol particles, and other important materials, but also in foods, to slow the deterioration in their flavor. Terpenes don't prevent oxidation, but they do help reduce the body's production of DNA-damaging molecules that can cause cancer, and help control the growth of tumors. And some phenolic compounds and terpenes are antiinflammatory agents; they moderate the body's overreaction to cell damage, which can otherwise contribute to the development of both heart disease and cancer. The idea that herbs and spices have medicinal value is an ancient one, and grounded in fact: plants are virtuosos of biochemical invention, and have been the original source of many important drugs (aspirin, digitalis, quinine, taxol are just a few). The health effects of plant foods in general are discussed above, p. 253. Herbs and spices, with their specialization in phenolic and terpene compounds, are notable for three broadly helpful tendencies. Phenolic compounds often have antioxidant activity; oregano, bay leaf, dill, rosemary, and turmeric are among the most effective. Antioxidants are useful both in the body, to prevent damage to DNA, cholesterol particles, and other important materials, but also in foods, to slow the deterioration in their flavor. Terpenes don't prevent oxidation, but they do help reduce the body's production of DNA-damaging molecules that can cause cancer, and help control the growth of tumors. And some phenolic compounds and terpenes are antiinflammatory agents; they moderate the body's overreaction to cell damage, which can otherwise contribute to the development of both heart disease and cancer.

The Relative Strengths of Pungent Chemicals in Black Pepper, Chillis, and GingerIn this list, the pungency of piperine, the active ingredient in black pepper, is arbitrarily set at 1. The ingredients in ginger and grains of paradise are similar in strength, while the capsaicins in chillis are much stronger. The actual pungency of a given spice depends both on the ident.i.ty of the active ingredient and its concentration in the spice.

Pungent Compound Spice Spice Relative Pungency Relative Pungency

Piperine Black pepper Black pepper 1 1.

Gingerol Ginger, fresh Ginger, fresh 0.8 0.8.

Shogaol Ginger, old (from gingerol) Ginger, old (from gingerol) 1.5 1.5.

Zingerone Ginger, heated (from gingerol) Ginger, heated (from gingerol) 0.5 0.5.

Paradol Grains of paradise Grains of paradise 1 1.

Capsaicin Chilli Chilli 150300 150300

Capsaicin variants Chilli Chilli 8590 8590

We don't yet know whether the consumption of herbs and spices can significantly reduce the risk of any disease; but it's a real possibility.

Herbs, Spices, and Food Poisoning It has been suggested that people first began to use herbs and spices, particularly in tropical countries, because their defensive chemicals help control the microbes that cause food poisoning, and thus made food safer to eat. While some - garlic, cinnamon, cloves, oregano, thyme - are fairly effective at killing important disease microbes, most are not. And many, especially black pepper and others that take several days to dry in tropical climates, carry millions of microbes in every pinch, sometimes including It has been suggested that people first began to use herbs and spices, particularly in tropical countries, because their defensive chemicals help control the microbes that cause food poisoning, and thus made food safer to eat. While some - garlic, cinnamon, cloves, oregano, thyme - are fairly effective at killing important disease microbes, most are not. And many, especially black pepper and others that take several days to dry in tropical climates, carry millions of microbes in every pinch, sometimes including E. coli E. coli and disease-causing species of and disease-causing species of Salmonella, Bacillus, Salmonella, Bacillus, and and Aspergillus. Aspergillus. This is why spices are often fumigated with various chemicals (ethylene or propylene oxide in the United States) or steamed. About 10% of imported spices are irradiated to eradicate microbes. This is why spices are often fumigated with various chemicals (ethylene or propylene oxide in the United States) or steamed. About 10% of imported spices are irradiated to eradicate microbes.

Handling and Storing Herbs and Spices Preserving Aroma Compounds The aim in handling herbs and spices is to retain their characteristic aroma compounds. The volatility of these compounds means that they readily evaporate, and their reactive nature means that they are likely to be altered if they're exposed to oxygen and moisture in the air, or to reaction-causing heat or light. To preserve herbs and spices, their tissues must be killed and dried out, so that they don't rot, but as gently as possible, so that water is removed without removing all the flavor. Then the dried material must be kept in closed containers, in a dark, cool place. As a general rule, herbs and spices keep best in opaque gla.s.s containers in the freezer (the container should be warmed to room temperature before opening to prevent moisture in the air from condensing onto cold flavorings). In practice, most cooks keep their flavorings at room temperature. As long as they aren't regularly exposed to strong light, whole spices keep well for a year, and ground spices for a few months. The fine particles of ground spices have a large surface area and lose their aroma molecules to the air more rapidly, while whole spices retain the aromas within intact cells.

Storing Fresh Herbs Many herbs are young, delicate stems and leaves, and so more fragile than other produce. Because their stems have been cut, they're likely to be producing the wound hormone ethylene, which in a closed container will acc.u.mulate and trigger general deterioration. Most are best stored in the refrigerator in partly open plastic bags, loosely wrapped in cloth or paper that will absorb moisture and prevent microbes from growing rapidly on wet leaves. Because they come from warm climates, basil and perilla suffer chilling injury in the refrigerator and so are best kept at room temperature, with freshly cut stems immersed in water.

The flavor of many herbs is well preserved by freezing, though the tissues suffer damage from ice crystals and become unattractively dark and limp when thawed. Immersion in oil, which protects the tissue from oxygen, also works for a few weeks, after which much of the flavor has oozed into the oil. Herbs in oil should always be kept in the refrigerator, because the same absence of oxygen that's good for flavor preservation is also good for the growth of botulism bacteria. The bacteria don't grow or produce toxins at refrigerator temperatures.

Drying Fresh Herbs Drying is a process that removes most of the water in an herb, which when fresh may be more than 90% water. The basic dilemma is that many aroma chemicals are more volatile than water, so any process that evaporates most of the water will also evaporate most of the flavor. This is why many dried herbs don't taste anything like the fresh version, and instead have a generic dried-leaf, hay aroma. There are a few exceptions to this rule, mainly Mediterranean herbs in the mint family that are native to hot, arid areas and have aromatics that persist in drying conditions (oregano, thyme, rosemary, as well as bay laurel from the laurel family). Though sundrying sounds appealing, its high temperatures and strong dose of visible and ultraviolet light mean that it generally removes and alters flavor. Air-drying over the course of a few days in the shade is much preferable. Herbs can be dried in just a few hours in a low oven or a dehydrator, but the higher temperature usually causes greater flavor losses than air-drying. Some commercial herbs are freeze-dried, which often preserves more of the original flavor.

The microwave oven turns out to work fairly well for drying small quant.i.ties of herbs, thanks to the selective and rapid effects of its radiation. Microwave energy excites water molecules while leaving non-polar oil molecules relatively unaffected, and it penetrates instantly throughout thin leaves and stems (p. 786). This means that all the water molecules in a batch of herbs reach the boiling point within a few seconds and begin to escape from the leaves, while the structures containing the oil-like flavor compounds (glands and ca.n.a.ls, pp. 402 and 407) heat up more gradually and indirectly, via the heat of the water molecules. The herbs dry in a matter of a few minutes, with less drastic flavor losses than result from ordinary oven drying.

Cooking With Herbs and Spices Herbs and spices are generally cooked along with other ingredients, and as a relatively minor component of the mixture, 1% or less of the total weight. This section explores the extraction and transformation of flavor in such dishes. But some preparations rely on flavorings to provide more than just flavor (p. 401). And a number of herbs - parsley, sage, basil - are delicious on their own, deep-fried just long enough to become crisp and mellow their flavor.

Flavor Extraction For herbs and spices to provide us with flavor, cooks must find ways to liberate the flavor chemicals from within their tissue and convey them to our taste and odor receptors. For fragile herbs, this may be as simple as strewing the fresh leaves on the dish, as in Vietnamese soups: the eater liberates the aromas by chewing on the leaves, and enjoys them at their freshest. But if the flavors are to be incorporated into the dish, then the flavor compounds must somehow escape from the herb or spice. The cook may leave the flavoring intact and use liquids and heat to encourage the flavors to seep out gradually, or he may break it into particles - chopping fresh herbs, crumbling dry ones, grinding spices - to expose the flavor molecules directly to the dish. The finer the crumble or grind, the greater the surface area from which flavor molecules can escape, and so the more rapidly the flavor moves from flavoring into dish.

Rapid extraction may or may not be desirable. In a briefly cooked dish, it's essential. In a long-cooked stew, however, a slower release from coa.r.s.er particles or whole leaves and seeds may be preferable. In pickles and preserves, whole spices provide flavor without clouding the liquid. Once flavor molecules have been extracted into a preparation, they begin to react with oxygen and with other food molecules, and their original flavor is transformed, however subtly. Larger particles release the original flavors over a longer time. Another way to a.s.sure some fresh flavors in a long-cooked dish is to add the herb or spice - either altogether or a supplemental dose - toward the end of cooking, or even after the cooking is done.

Prepared flavor extracts such as vanilla extract are handy because the flavor molecules have already been dissolved in a liquid and immediately permeate the dish. Because cooking will only cause their flavor to evolve or to evaporate, extracts are best added toward the end of a preparation.

Grinding, Crushing, Chopping There are several ways of crushing herbs and spices, and they have different effects on flavor. Grinders, choppers, and mortars all generate heat. The hotter the aroma molecules get, the more volatile they become and the more readily they escape, and the more reactive and changeable they become. The original flavors are best preserved by prechilling both spice and grinder to keep the aromatics as cool as possible. Food processors slice into herbs and introduce a lot of air and therefore aroma-altering oxygen, while a pestle pounding in a mortar crushes herbs and minimizes aeration. Careful chopping with a sharp knife leaves much of the herb structure intact to provide fresh flavor while minimizing cell damage to the cut edges; by contrast, a dull knife crushes rather than cuts, bruises a wide swath of cells, and can result in rapid brown-black discoloration. There are several ways of crushing herbs and spices, and they have different effects on flavor. Grinders, choppers, and mortars all generate heat. The hotter the aroma molecules get, the more volatile they become and the more readily they escape, and the more reactive and changeable they become. The original flavors are best preserved by prechilling both spice and grinder to keep the aromatics as cool as possible. Food processors slice into herbs and introduce a lot of air and therefore aroma-altering oxygen, while a pestle pounding in a mortar crushes herbs and minimizes aeration. Careful chopping with a sharp knife leaves much of the herb structure intact to provide fresh flavor while minimizing cell damage to the cut edges; by contrast, a dull knife crushes rather than cuts, bruises a wide swath of cells, and can result in rapid brown-black discoloration.

Some Cla.s.sic Mixtures of Herbs and Spices France

Bouquet garni

Bay, thyme, parsley Bay, thyme, parsley

Fines herbes

Tarragon, chervil, chive Tarragon, chervil, chive

Quatre epices

Black pepper, nutmeg, clove, cinnamon Black pepper, nutmeg, clove, cinnamon

Herbes de Provence

Thyme, marjoram, fennel, basil, rosemary, lavender Thyme, marjoram, fennel, basil, rosemary, lavender

Morocco

Chermoula

Onion, garlic, coriander leaf, chilli, c.u.min, black pepper, saffron Onion, garlic, coriander leaf, chilli, c.u.min, black pepper, saffron

Ras el hanout

20+, including cardamom, ca.s.sia, mace, clove, c.u.min, chilli, rose petals 20+, including cardamom, ca.s.sia, mace, clove, c.u.min, chilli, rose petals

Middle East