On Food And Cooking Part 40

Nettles Nettles ( Nettles (Urtica dioica) are a common Eurasian weed that has now spread throughout the Northern Hemisphere. They're notorious for their stinging hairs, which have a brittle silicate tip and a gland that supplies a c.o.c.ktail of irritant chemicals, including histamine, for injection when skin meets needle. The hairs can be disarmed by a quick blanch in boiling water, which releases and dilutes the chemicals. But the harvest and was.h.i.+ng require protective gloves. Nettles are made into soup, stewed, and mixed with cheese to stuff pasta.

Purslane Purslane ( Purslane (Portulaca oleracea) is a low-lying weed with fat stems and small thick leaves, which thrives in midsummer heat on neglected ground. It's a European native that has spread throughout the world. One nickname for purslane is pig-weed, and the 19th century Englishman William Cobbett said it was suitable only for pigs and the French. But people in many countries enjoy its combination of tartness and soothing, mucilaginous smoothness, both raw in salads and added to meat and vegetable dishes during the last few minutes of cooking. There are now cultivated varieties with larger leaves shaded yellow and pink. Its qualities are similar to those of the cactus pad because both have adapted in similar ways to hot, dry habitats (p. 316). Purslane is notable for its content of calcium, several vitamins, and an omega-3 fatty acid, linolenic acid (p. 801).

Flowers: Artichokes, Broccoli, Cauliflower, and Others Flowers As Foods Flowers are plant organs that attract pollinating animals with a strong scent, bright colors, or both; so they can add both aromatic and visual appeal to our foods. But the most important edible flowers in the West are neither colorful nor flowery! Broccoli and cauliflower are immature or developmentally arrested flower structures, and artichokes are eaten before they have a chance to open. Aromatic flowers have played a more prominent role in the Middle East and Asia. In the Middle East, the distilled essence of indigenous roses, and later of bitter orange flowers from China, has long been used to embellish the flavors of many dishes, rosewater in baklava and "Turkish delight," for example, and orange-flower water in Moroccan salads and stews and in Turkish coffee. Food historian Charles Perry has called these extracts "the vanilla of the Middle East." They were commonly used in the West as well until vanilla displaced them in the middle of the 19th century.

Many flowers can be and are used as edible garnishes, or cooked into aromatic fritters, or infused to make a tea or sorbet. The petals are the main source of volatile chemicals, which are held in surface cells or specialized oil glands. Both the petals and their flavors are delicate, so they should be cooked very briefly or added at the last minute. Flower petals are candied by brief cooking in a strong sugar syrup, or by brus.h.i.+ng them gently with egg white or a solution of gum arabic, dusting them with sugar, and allowing them to dry. In the second technique, the egg white provides both antimicrobial proteins (p. 77) and a sticky liquid for the sugar to dissolve into, and the concentrated sugar pulls water out of any surviving microbes. When working with flowers, the cook should observe two cautions: avoid flowers that are known to contain defensive plant toxins, or that may have been treated with pesticides or fungicides in the greenhouse or garden.

Some Edible and Inedible Flowers Edible Flowers Herbs (chive, rosemary, lavender) Rose Violet, pansy Daylily Begonia Jasmine Geranium (many herb and fruit scents) Lilac Orchids Chrysanthemum, marigold Lotus Nasturtium Elderflower Citrus Apple, pear Tulip Gardenia Peony Linden (tilleul) Redbud Inedible Flowers Lily of the valley Hydrangea Narcissus, daffodil Oleander Poinsettia Rhododendron Sweet pea Wisteria Banana Flowers Banana flowers are the large male portion of the tropical banana tree's flower and its protective layers. They're somewhat astringent from the presence of tannins, and are cooked as a vegetable. Banana flowers are the large male portion of the tropical banana tree's flower and its protective layers. They're somewhat astringent from the presence of tannins, and are cooked as a vegetable.

Daylily Buds Daylily buds, mostly from species of Daylily buds, mostly from species of Hemerocallis, Hemerocallis, are eaten both fresh and dried in Asia - the dried form is sometimes called "golden needles" - and provide a valuable supplement of carotenoid and phenolic antioxidants. are eaten both fresh and dried in Asia - the dried form is sometimes called "golden needles" - and provide a valuable supplement of carotenoid and phenolic antioxidants.

Roselle, Hibiscus, and Jamaica These are all names for the bright red, tart, aromatic fleshy flower covering (the These are all names for the bright red, tart, aromatic fleshy flower covering (the calyx, calyx, more familiar as the leaf-like stubs at the base of a strawberry) of a kind of hibiscus. more familiar as the leaf-like stubs at the base of a strawberry) of a kind of hibiscus. Hibiscus sabdariffa Hibiscus sabdariffa is a native of Africa and a relative of okra. It's much used in Mexico and the Caribbean, sometimes fresh, sometimes dried and infused to make drinks, sometimes rehydrated and cooked with other ingredients. In the United States it's most familiar as an ingredient in Hawaiian punch and many red herbal teas (the pigments are anthocyanins). Jamaica ("ha-MY-ka") is remarkable for being a concentrated source of vitamin C, phenolic antioxidants, and gel-forming pectin. is a native of Africa and a relative of okra. It's much used in Mexico and the Caribbean, sometimes fresh, sometimes dried and infused to make drinks, sometimes rehydrated and cooked with other ingredients. In the United States it's most familiar as an ingredient in Hawaiian punch and many red herbal teas (the pigments are anthocyanins). Jamaica ("ha-MY-ka") is remarkable for being a concentrated source of vitamin C, phenolic antioxidants, and gel-forming pectin.

Squash Blossoms The large flowers of zucchini and its relatives (p. 332) are sometimes stuffed, and variously deep-fried or chopped and added to soups or egg dishes. Their aroma is musky and complex, with green, almond, spicy, violet, and barnyard notes. The large flowers of zucchini and its relatives (p. 332) are sometimes stuffed, and variously deep-fried or chopped and added to soups or egg dishes. Their aroma is musky and complex, with green, almond, spicy, violet, and barnyard notes.

Artichokes The artichoke is the large flower bud of a kind of thistle, Cynara scolymus, Cynara scolymus, native to the Mediterranean region. It was probably developed from the cardoon, native to the Mediterranean region. It was probably developed from the cardoon, C. cardunculus, C. cardunculus, which has small and meager buds whose base and stem were eaten in ancient Greece. Artichokes were a delicacy in Rome, a fact of which Pliny professed to be ashamed: "thus we turn into a corrupt feast the earth's monstrosities, those which even the animals instinctively avoid" (Book19). The name is a corruption, via Italian, of the Arabic which has small and meager buds whose base and stem were eaten in ancient Greece. Artichokes were a delicacy in Rome, a fact of which Pliny professed to be ashamed: "thus we turn into a corrupt feast the earth's monstrosities, those which even the animals instinctively avoid" (Book19). The name is a corruption, via Italian, of the Arabic al' qarshuf, al' qarshuf, meaning "little cardoon"; food historian Charles Perry suggests that the large buds we know today, several inches in diameter, were developed in the late Middle Ages in Moorish Spain. meaning "little cardoon"; food historian Charles Perry suggests that the large buds we know today, several inches in diameter, were developed in the late Middle Ages in Moorish Spain.

The artichoke. The "heart" is the flower base and corresponds to the fleshy portion of the strawberry and fig.

Thistles are members of the lettuce family and so relatives of salsify and sun-chokes, all of which share a similar flavor. The edible parts of the artichoke are the fleshy bases of the bracts, or protective leaves, and the heart, which is actually the base of the flower structure, the upper part of the stalk. The "choke" is made up of the actual flowerets, which if allowed to bloom turn a deep violet-blue. The small artichokes sometimes seen in markets or in jars come from flowering stalks low on the plant rather than the main stalk. They grow very slowly, and so are picked at an immature stage when there's little or no choke inside.

The qualities of the artichoke are largely determined by its copious content of phenolic substances, which manifest themselves immediately when the flesh is cut or tasted raw. Cut surfaces turn brown very quickly as the phenolics react with oxygen to form colored complexes, and raw slices are noticeably astringent thanks to the reaction of phenolics with our salivary proteins. Cooking minimizes both effects. By disrupting the cells, it causes the phenolics to bind to a host of different molecules including each other; this gives the flesh an evenly dark tone, and leaves few phenolics free to cause astringency. Some artichoke phenolics have antioxidant and cholesterol-lowering effects, and one in particular, a compound dubbed cynarin, has the unusual effect of making foods eaten after a bite of artichoke taste sweet. Cynarin apparently inhibits the sweet receptors on our taste buds, so when it's swept off the tongue by the next bite, the receptors start up again, and we notice the contrast. Because they therefore distort the flavor of other foods, artichokes are thought to be an inappropriate accompaniment to fine wines.

The Cabbage Family: Broccoli, Cauliflower, Romanesco These vegetables are all varieties of cabbage in which the normal development of flower stalks and flowers is arrested, so that the immature flowering tissues proliferate and acc.u.mulate into large ma.s.ses. Based on recent genetic and geographic a.n.a.lysis, it appears that broccoli arose in Italy and in turn gave rise to cauliflower, which was known in Europe by the 16th century.

In the case of broccoli, extra flower-stalk tissue develops, fuses into thick "spears," and then goes on to produce cl.u.s.ters of small green flower buds. In cauliflower and its interestingly angular, green variant, romanesco, the stalk-production stage is extended indefinitely and forms a dense ma.s.s or "curd" of immature flowerstalk branches. Because the curd is developmentally immature, it remains relatively unfibrous and rich in cell-wall pectins and hemicelluloses (p. 265), and so can be pureed to a very fine, creamy consistency (and if overcooked whole, it readily turns to mush). To get as white a cauliflower curd as possible, growers usually tie the leaves over it to protect it from sunlight, which induces the production of yellowish pigments.

Broccoli rabe, slender stalks topped with a small cl.u.s.ter of flower buds, is unrelated to true broccoli. The name is a corruption of "broccoletti di rape," or "little sprouts of turnip," and refers to a variety of turnip that bears somewhat thickened flower stalks along its main stalk. Broccoli rabe is notably more bitter than true broccoli. Broccolini, similar to broccoli rabe but less bitter, is a recent hybrid between European and Asian bra.s.sicas.

Fruits Used as Vegetables The botanical fruits that cooks treat as vegetables generally require cooking to make them interesting or soft enough to eat. The two familiar exceptions to this rule are tomatoes and cuc.u.mbers, frequently served raw in salads.

The Nightshade Family: Tomato, Capsic.u.ms, Eggplant, and Others This remarkable plant family includes several of the world's most popular vegetables as well as tobacco and deadly nightshade; in fact it was the tomato's resemblance to nightshade that slowed its acceptance in Europe. Members of the nightshade family share the habit of stock-piling chemical defenses, usually bitter alkaloids. Many generations of selection and breeding have reduced these defenses in most edible nightshade fruits, though their leaves are often still toxic. There's one nightshade defense that humans have fallen in love with: the pungent capsaicins of the chilli "peppers." Chillis are the most popular spice in the world; their pungency is discussed in chapter 8. In this section I'll describe the milder capsic.u.ms that are eaten as vegetables.

Tomatoes Tomatoes started out as small, bitter berries growing on bushes in the west coast deserts of South America. Today, after their domestication in Mexico (their name comes from the Aztec term for "plump fruit," Tomatoes started out as small, bitter berries growing on bushes in the west coast deserts of South America. Today, after their domestication in Mexico (their name comes from the Aztec term for "plump fruit," tomatl tomatl), and a period of European suspicion that lasted into the 19th century, they're eaten all over the world in a great variety of sizes, shapes, and carotenoid-painted colors. In the United States they're second in vegetable popularity only to the potato, a starchy staple.

What accounts for their great appeal? And why are these sweet-tart fruits treated as a vegetable? I think that the answers lie in their unique flavor. In addition to a relatively low sugar content for a fruit (3%), similar to that of cabbage and brussels sprouts, ripe tomatoes have an unusually large amount of savory glutamic acid (as much as 0.3% of their weight), as well as aromatic sulfur compounds. Glutamic acid and sulfur aromas are more common in meats than fruits, and so predispose them to complement the flavor of meats, even to replace that flavor, and certainly to add depth and complexity to sauces and other mixed preparations. (This may also be why although many rotten fruits smell pleasantly fermented, rotten tomatoes are absolutely foul!) In any case, tomatoes are a good thing to like. They're rich in vitamin C, and the standard red varieties give us an excellent dose of the antioxidant carotenoid lycopene, which is especially concentrated in tomato paste and ketchup.

Vegetables in the Nightshade Family

Potato

Solanum tuberosum Solanum tuberosum

Eggplant

Solanum melongena; S. aethiopic.u.m, macrocarpon Solanum melongena; S. aethiopic.u.m, macrocarpon

Tomato

Lycopersicon esculentum Lycopersicon esculentum

Capsic.u.ms, chillis

Capsic.u.m Capsic.u.m species species

Bell, pimiento, paprika, jalapeno, serrano, poblano...

C. annuum C. annuum

Tabasco

C. frutescens C. frutescens

Scotch bonnet, habanero

C. chinense C. chinense

Aji

C. baccatum C. baccatum

Manzano

C. p.u.b.escens C. p.u.b.escens

Tomatillo

Physalis ixocarpa, P. philadelphica Physalis ixocarpa, P. philadelphica

Tree tomato

Cyphomandra betacea Cyphomandra betacea

Tomato Anatomy and Flavor Aside from the relatively dry paste varieties, most tomatoes have four different kinds of tissue: a thin, tough cuticle, or skin, which is sometimes removed; the outer fruit wall; the central pith; and a semiliquid jelly and juice surrounding the seeds. The wall tissue contains most of the sugars and amino acids, while the concentration of acid in the jelly and juice is double that of the wall. And most of the aroma compounds are found in the cuticle and wall. The flavor of a tomato slice thus depends on the relative proportions of these tissues. Many cooks prepare tomatoes for cooking by first removing the skin, seedy jelly, and juice. This practice makes the tomato flesh more refined and less watery, but it changes the flavor balance in favor of sweetness, and sacrifices aroma. The tomato's citric and malic acids aren't volatile and don't cook away, so acidity and some aroma can be restored by cooking the skins, jelly, and juice together until much of the liquid has evaporated, then straining the remainder into the cooking tomato flesh. As cooks have long known and flavor chemists have verified, the overall flavor of tomatoes can be intensified by the addition of both sugar and acidity. Aside from the relatively dry paste varieties, most tomatoes have four different kinds of tissue: a thin, tough cuticle, or skin, which is sometimes removed; the outer fruit wall; the central pith; and a semiliquid jelly and juice surrounding the seeds. The wall tissue contains most of the sugars and amino acids, while the concentration of acid in the jelly and juice is double that of the wall. And most of the aroma compounds are found in the cuticle and wall. The flavor of a tomato slice thus depends on the relative proportions of these tissues. Many cooks prepare tomatoes for cooking by first removing the skin, seedy jelly, and juice. This practice makes the tomato flesh more refined and less watery, but it changes the flavor balance in favor of sweetness, and sacrifices aroma. The tomato's citric and malic acids aren't volatile and don't cook away, so acidity and some aroma can be restored by cooking the skins, jelly, and juice together until much of the liquid has evaporated, then straining the remainder into the cooking tomato flesh. As cooks have long known and flavor chemists have verified, the overall flavor of tomatoes can be intensified by the addition of both sugar and acidity.

Tomatoes that are allowed to ripen fully on the vine acc.u.mulate more sugar, acid, and aroma compounds, and have the fullest flavor. An important element of ripe-tomato flavor is provided by the aroma compound furaneol, which resembles sweet-savory caramel (it also contributes to the flavors of ripe strawberries and pineapples). Most supermarket tomatoes are picked and s.h.i.+pped while still green and artificially stimulated to redden by treatment with ethylene gas (p. 351), so they have little ripe-fruit flavor, and in fact have become a byword for flavorless produce. However, parts of Europe and Latin America prefer to make salads with less fruity, more vegetable-like mature green tomatoes, and people in many regions cook (or pickle) and enjoy green tomatoes for their own kind of savoriness. And in rural Peru, the prized varieties of both tomato and tomatillo are frankly bitter.

Cooked Tomatoes When fresh tomatoes are cooked down to make a thick sauce, they gain some flavors - notably rose-and violet-like fragments of the carotenoid pigments - but they lose the fresh "green" notes provided by unstable fragments of fatty acids and by a particular sulfur compound (a thiazole). Because tomato leaves have a p.r.o.nounced fresh-tomato aroma thanks to their leaf enzymes (p. 273) and prominent aromatic oil glands, some cooks add a few leaves to a tomato sauce toward the end of the cooking, to restore its fresh notes. Tomato leaves have long been considered potentially toxic because they contain a defensive alkaloid, tomatine, but recent research has found that tomatine binds tightly to cholesterol molecules in our digestive system, so that the body absorbs neither the alkaloid nor its bound partner. It thus reduces our net intake of cholesterol! (Green tomatoes also contain tomatine and have the same effect.) It's fine, then, to freshen the flavor of tomato sauces with the leaves. When fresh tomatoes are cooked down to make a thick sauce, they gain some flavors - notably rose-and violet-like fragments of the carotenoid pigments - but they lose the fresh "green" notes provided by unstable fragments of fatty acids and by a particular sulfur compound (a thiazole). Because tomato leaves have a p.r.o.nounced fresh-tomato aroma thanks to their leaf enzymes (p. 273) and prominent aromatic oil glands, some cooks add a few leaves to a tomato sauce toward the end of the cooking, to restore its fresh notes. Tomato leaves have long been considered potentially toxic because they contain a defensive alkaloid, tomatine, but recent research has found that tomatine binds tightly to cholesterol molecules in our digestive system, so that the body absorbs neither the alkaloid nor its bound partner. It thus reduces our net intake of cholesterol! (Green tomatoes also contain tomatine and have the same effect.) It's fine, then, to freshen the flavor of tomato sauces with the leaves.

Tomato anatomy. The fruit wall is especially rich in sugars, amino acids, and aroma molecules, the jelly in sugarbalancing acids.

Fresh tomatoes readily cook down to a smooth puree, but many canned tomatoes don't. Canners frequently add calcium salts to firm the cell walls and keep the pieces intact, and this can interfere with their disintegration during cooking. If you want to make a fine-textured dish from canned tomatoes, check the labels and buy a brand that doesn't list calcium among its ingredients.

Storage Tomatoes came originally from a warm climate, and should be stored at room temperature. Their fresh flavor readily suffers from refrigeration. Tomatoes at the mature-green stage are especially sensitive to chilling at temperatures below about 55F/13C, and suffer damage to their membranes that results in minimal flavor development, blotchy coloration, and a soft, mealy texture when they're brought back to room temperature. Fully ripe tomatoes are less sensitive, but lose flavor due to the loss of flavor-producing enzyme activity. Some of this activity can come back, so refrigerated tomatoes should be allowed to recover at room temperature for a day or two before eating. Tomatoes came originally from a warm climate, and should be stored at room temperature. Their fresh flavor readily suffers from refrigeration. Tomatoes at the mature-green stage are especially sensitive to chilling at temperatures below about 55F/13C, and suffer damage to their membranes that results in minimal flavor development, blotchy coloration, and a soft, mealy texture when they're brought back to room temperature. Fully ripe tomatoes are less sensitive, but lose flavor due to the loss of flavor-producing enzyme activity. Some of this activity can come back, so refrigerated tomatoes should be allowed to recover at room temperature for a day or two before eating.

The "tree tomato" is the vaguely tomato-like fruit of a woody plant in the nightshade family. It comes in red and yellow types and has a tough peel and bland flavor.

Tomatillos Tomatillos are the fruits of Tomatillos are the fruits of Physalis ixocarpa, Physalis ixocarpa, a tomato relative that in fact was cultivated before the tomato in Mexico and Guatemala, to whose cool highlands it is better adapted. The tomatillo fruit is smaller than a standard tomato but similar in structure, and is borne on the plant enclosed in a papery husk. Its skin is thick and tough, sticky with a water-soluble secretion (the plant's species name, a tomato relative that in fact was cultivated before the tomato in Mexico and Guatemala, to whose cool highlands it is better adapted. The tomatillo fruit is smaller than a standard tomato but similar in structure, and is borne on the plant enclosed in a papery husk. Its skin is thick and tough, sticky with a water-soluble secretion (the plant's species name, ixocarpa, ixocarpa, means "sticky fruit"), that helps it keep well for several weeks. The tomatillo remains green when ripe and has a tart but otherwise mild, green flavor, a relatively firm and dry texture. It's usually cooked and/or pureed into sauces, with other ingredients adding depth or strength of flavor. A related species, means "sticky fruit"), that helps it keep well for several weeks. The tomatillo remains green when ripe and has a tart but otherwise mild, green flavor, a relatively firm and dry texture. It's usually cooked and/or pureed into sauces, with other ingredients adding depth or strength of flavor. A related species, P. philadelphica, P. philadelphica, provides an esteemed purple version called provides an esteemed purple version called miltomate. miltomate.

Capsic.u.ms or Sweet Peppers Capsic.u.ms, like tomatoes, are fruits of the New World that conquered the Old. They were domesticated in South America, and are now a defining element of the cuisines of Mexico, Spain, Hungary, and many countries in Asia (the countries with the highest per capita consumption are Mexico and Korea). This triumph is due largely to the defensive chemical capsaicin, which activates pain and heat receptors in our mouths, and which many human cultures have perversely come to love. This spicy aspect of the chillis is what inspired Columbus to call them peppers, though they're not at all related to true black pepper. ( Capsic.u.ms, like tomatoes, are fruits of the New World that conquered the Old. They were domesticated in South America, and are now a defining element of the cuisines of Mexico, Spain, Hungary, and many countries in Asia (the countries with the highest per capita consumption are Mexico and Korea). This triumph is due largely to the defensive chemical capsaicin, which activates pain and heat receptors in our mouths, and which many human cultures have perversely come to love. This spicy aspect of the chillis is what inspired Columbus to call them peppers, though they're not at all related to true black pepper. (Chilli was the Aztec term.) For chillis as spices, see chapter 8. was the Aztec term.) For chillis as spices, see chapter 8.

Capsic.u.ms are essentially hollow berries, with a relatively thin, crisp wall of storage cells (spice types have been selected for very thin, easily dried fruits; vegetable types such as the pimiento have been bred for meatier walls). There are five domesticated species in the chilli genus Capsic.u.m, Capsic.u.m, with most vegetable types coming from with most vegetable types coming from C. annuum. C. annuum. Many varieties have been developed that are mild enough to be eaten as vegetables rather than condiments, and with a range of colors, shapes, sweetnesses, and aromas. Capsic.u.ms ripen to shades of yellow, brown, purple, or red, depending on the mix of pigments (purple comes from anthocyanins, brown from the combination of red carotenoids and green chlorophyll), but all can be picked and eaten green. The familiar green bell pepper has a strong, distinctive aroma thanks to a particular compound (isobutyl methoxypyrazine) carried in oil droplets within its cells; the very same compound occasionally pops up in cabernet sauvignon and sauvignon blanc wines and gives them a usually unwelcome green-vegetable note. Green fruits and mature yellow varieties are also rich in the carotenoid lutein, which helps prevent oxidative damage in the eye (p. 256). In red varieties, both lutein and the green aroma disappear during ripening along with chlorophyll, and other carotenoid pigments acc.u.mulate, the main ones being capsanthin, capsorubin, as well as beta-carotene, the precursor of vitamin A. Mature red capsic.u.ms are among the richest carotenoid sources we have; paprika powder may be more than 1% pigment by weight. They're also rich in vitamin C. And thanks to their content of cell-wall pectins, both fresh and rehydrated dried capsic.u.ms develop a thick, smooth consistency when cooked and pureed for a soup or sauce. Many varieties have been developed that are mild enough to be eaten as vegetables rather than condiments, and with a range of colors, shapes, sweetnesses, and aromas. Capsic.u.ms ripen to shades of yellow, brown, purple, or red, depending on the mix of pigments (purple comes from anthocyanins, brown from the combination of red carotenoids and green chlorophyll), but all can be picked and eaten green. The familiar green bell pepper has a strong, distinctive aroma thanks to a particular compound (isobutyl methoxypyrazine) carried in oil droplets within its cells; the very same compound occasionally pops up in cabernet sauvignon and sauvignon blanc wines and gives them a usually unwelcome green-vegetable note. Green fruits and mature yellow varieties are also rich in the carotenoid lutein, which helps prevent oxidative damage in the eye (p. 256). In red varieties, both lutein and the green aroma disappear during ripening along with chlorophyll, and other carotenoid pigments acc.u.mulate, the main ones being capsanthin, capsorubin, as well as beta-carotene, the precursor of vitamin A. Mature red capsic.u.ms are among the richest carotenoid sources we have; paprika powder may be more than 1% pigment by weight. They're also rich in vitamin C. And thanks to their content of cell-wall pectins, both fresh and rehydrated dried capsic.u.ms develop a thick, smooth consistency when cooked and pureed for a soup or sauce.

Eggplants, or Aubergines Eggplants are the only major vegetable in the nightshade family that came from the Old World. An early ancestor may have floated from Africa to India or Southeast Asia, where it was domesticated, and where small, bitter varieties are still appreciated as a condiment. Arab traders brought it to Spain and north Africa in the Middle Ages, and it was eaten in Italy in the 15th century, in France by the 18th. (The etymology of Eggplants are the only major vegetable in the nightshade family that came from the Old World. An early ancestor may have floated from Africa to India or Southeast Asia, where it was domesticated, and where small, bitter varieties are still appreciated as a condiment. Arab traders brought it to Spain and north Africa in the Middle Ages, and it was eaten in Italy in the 15th century, in France by the 18th. (The etymology of aubergine aubergine mirrors this history; it comes via Spanish and Arabic from the Sanskrit name.) Thanks to its tropical origins, the eggplant doesn't keep well in the refrigerator; internal chilling damage leads to browning and off-flavors in a few days. mirrors this history; it comes via Spanish and Arabic from the Sanskrit name.) Thanks to its tropical origins, the eggplant doesn't keep well in the refrigerator; internal chilling damage leads to browning and off-flavors in a few days.

There are many varieties of eggplant, white-and orange-and purple-skinned, pea-and cuc.u.mber-and melon-sized, very mild and intensely bitter. Most market types are colored with purple anthocyanins, while a different species (S. aethiopic.u.m) provides the orange carotenoid types. All eggplants have a spongy interior, with many tiny air pockets between cells. When cooked, the air pockets collapse and the flesh consolidates into a fine-textured ma.s.s, sometimes creamy (most Asian varieties) and sometimes meaty (most European varieties) depending on the variety, maturity, and preparation. In baked ca.s.seroles - the Greek moussaka and Italian eggplant parmigiana - eggplant slices retain some structure; in the Middle Eastern dip baba ghanoush, grilled pureed eggplant provides the smooth, melting body that carries the flavors of sesame paste, lemon juice, and garlic.

Eggplant's spongy structure has two notable consequences for the cook. One is that eggplants shrink down to a relatively small volume when cooked. The other is that when fried, raw eggplant pieces soak up oil, leaving little on the pan for lubrication and making the vegetable very rich. In some preparations - such as the famous Arab dish Imam bayaldi, Imam bayaldi, "the priest fainted," in which halved eggplants are stuffed and baked in copious olive oil - this richness is desired and maximized. Otherwise, the absorptiveness of eggplant can be reduced by collapsing its spongy structure before frying. This is accomplished by precooking it - microwaving works well - or by salting slices to draw out moisture from the cells and into the air pockets. Salting is often recommended as a way to remove the bitterness sometimes found in older eggplants grown in dry conditions, but it probably just reduces our perception of the alkaloids (p. 640); the bulk of the cell fluids remains in the cells. "the priest fainted," in which halved eggplants are stuffed and baked in copious olive oil - this richness is desired and maximized. Otherwise, the absorptiveness of eggplant can be reduced by collapsing its spongy structure before frying. This is accomplished by precooking it - microwaving works well - or by salting slices to draw out moisture from the cells and into the air pockets. Salting is often recommended as a way to remove the bitterness sometimes found in older eggplants grown in dry conditions, but it probably just reduces our perception of the alkaloids (p. 640); the bulk of the cell fluids remains in the cells.

The Squash and Cuc.u.mber Family The squash or cucurbit family, the Cucurbitaceae, has made three broad contributions to human pleasure and nutrition. These are the sweet, moist melons described in the next chapter, the sweet, starchy, nutritious "winter" squashes, which are harvested fully mature and hard and keep for months, and the not-so-sweet, moist cuc.u.mber and "summer" squashes, which are harvested while immature and tender, and keep for a few weeks. ("Squash" comes from a Narragansett Indian word meaning "a green thing eaten raw.") When cooked, winter squashes develop a consistency and flavor something like those of a sweet potato, while the summer squashes and immature Asian gourds develop a mild but distinctive aroma and a translucent, slick, almost gelatinous texture. Fruits of Cucurbita maxima, Cucurbita maxima, the Hubbard and other winter squashes, can reach 300 lb/135 kg, and are the largest fruits of any plant. Most cucurbits produce a particular form of berry called a pepo, with a protective rind and a ma.s.s of storage tissue containing many seeds. All of them are native to warm climates, so they suffer from chill injury if stored at standard refrigerator temperatures. In addition to the flesh of their fruits, cucurbits also offer edible vines, flowers, and seeds. the Hubbard and other winter squashes, can reach 300 lb/135 kg, and are the largest fruits of any plant. Most cucurbits produce a particular form of berry called a pepo, with a protective rind and a ma.s.s of storage tissue containing many seeds. All of them are native to warm climates, so they suffer from chill injury if stored at standard refrigerator temperatures. In addition to the flesh of their fruits, cucurbits also offer edible vines, flowers, and seeds.

Winter Squashes Winter squashes were domesticated in the Americas beginning around 5000 Winter squashes were domesticated in the Americas beginning around 5000 BCE BCE. They are both nutritious - many are rich in beta-carotene and other carotenoids as well as starch - and versatile. The flesh of most varieties is firm enough to saute or stew in chunks (fibrous spaghetti squash is an exception), but once cooked it also can be pureed to a very fine consistency; and its moderate sweetness makes it suitable for both savory and sweet preparations, from soups or side dishes to pies and custards. Their tough, dry skin and hollow structure encourage their use as edible containers; they can be filled with sweet or savory liquids, then baked, and eaten along with their contents. Winter squashes can be stored for months and many are available year-round, but they're at their prime shortly after harvest in late fall. They keep best at a temperature around 55F/15C and in relatively dry conditions (5070% relative humidity).

The Squash FamilyAsian and African Species

Cuc.u.mber

Cuc.u.mis sativus Cuc.u.mis sativus

Gherkin

Cuc.u.mis anguria Cuc.u.mis anguria

Melons: cantaloupe, honeydew, etc.

Cuc.u.mis melo Cuc.u.mis melo

Watermelon

Citrullus lanatus Citrullus lanatus

Winter/fuzzy melon, wax gourd