On Food And Cooking Part 41

Benincasa hispida Benincasa hispida

Luffa, ridged gourd

Luffa acutangula Luffa acutangula

Bottle gourd, cucuzza, calabash

Lagenaria siceraria Lagenaria siceraria

Bitter gourd, bitter melon

Momordica charantia Momordica charantia

South and North American Species

Summer and acorn squash, zucchini, pumpkin, spaghetti squash

Cucurbita pepo Cucurbita pepo

Winter squash: b.u.t.ternut, cheese, kabocha

Cucurbita moschata Cucurbita moschata

Winter squash: Hubbard, turban, banana, kabocha

Cucurbita maxima Cucurbita maxima

Cushaw

Cucurbita mixta Cucurbita mixta

Chayote, mirliton

Sechium edule Sechium edule

Summer Squashes Summer squashes have been bred into a delightful variety of shapes. There are scallops or pattypans, flat and scalloped around the edges; crooknecks and straight necks, with constricted stem ends; elongated vegetable marrows, or zucchinis; acorn squash; and distinctive Middle Eastern and Asian types as well. Some are green-skinned, some vibrantly yellow with carotenoid pigments, some variegated, and all have a pale, delicately spongy flesh that softens quickly when cooked. They're sweetest when picked young, and keep for a few weeks at 4550F/710C. Summer squashes have been bred into a delightful variety of shapes. There are scallops or pattypans, flat and scalloped around the edges; crooknecks and straight necks, with constricted stem ends; elongated vegetable marrows, or zucchinis; acorn squash; and distinctive Middle Eastern and Asian types as well. Some are green-skinned, some vibrantly yellow with carotenoid pigments, some variegated, and all have a pale, delicately spongy flesh that softens quickly when cooked. They're sweetest when picked young, and keep for a few weeks at 4550F/710C.

Cuc.u.mbers The cuc.u.mber was domesticated in India around 1500 The cuc.u.mber was domesticated in India around 1500 BCE BCE, arrived in the Mediterranean region about a thousand years later, and is now the second most important cucurbit worldwide after the watermelon. Like the watermelon, cuc.u.mbers are notable for their crisp, moist, mild, refreshing character. They're mainly consumed raw or pickled, and sometimes juiced to make a delicately flavored liquid for use in salad dressings, poaching fish, and other procedures. The distinctive yet melon-like aroma of cuc.u.mbers develops when the flesh is cut or chewed, and comes from the action of enzymes that break long membrane fatty-acid molecules into smaller chains that are 9 carbon atoms long; the characteristic melon fragments are alcohols, the cuc.u.mber fragments aldehydes. The larger a cuc.u.mber grows, the lower its acidity and the higher its modest sugar content (12%).

Cuc.u.mber Types There are five broad groups of cuc.u.mber varieties. Middle Eastern and Asian types are relatively small and thin. American pickling varieties are either smaller or slower-growing than "slicing" varieties, and have a thin skin to ease the penetration of brine. The standard American slicing cuc.u.mbers have been bred for the rigors of field production and long-distance distribution. They tend to be short and thick, with a relatively tough skin, dry flesh, prominent seeds, a strong cuc.u.mber flavor, and some bitterness at the stem end and just under the skin, thanks to the presence of defensive chemicals called cucurbitacins that discourage pests. European varieties, which are mainly grown in the controlled environment of greenhouses, are typically long and slender, with a thin tender skin, moist flesh, unformed seeds due to an absence of pollinating insects, a milder cuc.u.mber flavor, and no bitterness (breeders have eliminated the cucurbitacins). American cuc.u.mbers are often waxed to slow moisture loss, and so are almost always peeled before use, while European varieties are wrapped in plastic to accomplish the same purpose without compromising the edibility of their skin. There are five broad groups of cuc.u.mber varieties. Middle Eastern and Asian types are relatively small and thin. American pickling varieties are either smaller or slower-growing than "slicing" varieties, and have a thin skin to ease the penetration of brine. The standard American slicing cuc.u.mbers have been bred for the rigors of field production and long-distance distribution. They tend to be short and thick, with a relatively tough skin, dry flesh, prominent seeds, a strong cuc.u.mber flavor, and some bitterness at the stem end and just under the skin, thanks to the presence of defensive chemicals called cucurbitacins that discourage pests. European varieties, which are mainly grown in the controlled environment of greenhouses, are typically long and slender, with a thin tender skin, moist flesh, unformed seeds due to an absence of pollinating insects, a milder cuc.u.mber flavor, and no bitterness (breeders have eliminated the cucurbitacins). American cuc.u.mbers are often waxed to slow moisture loss, and so are almost always peeled before use, while European varieties are wrapped in plastic to accomplish the same purpose without compromising the edibility of their skin.

So-called "Armenian cuc.u.mbers" are actually an elongated African melon. True gherkins are the abundant p.r.i.c.kly fruits, round and about 1 in/2 cm long, of yet another African relative.

Bitter Gourds Bitter gourds have long been prized in Asia for a trait that's considered a defect in cuc.u.mbers, the presence of bitter cucurbitacins. There may be good reasons to cultivate a taste for cucurbitacins, because recent studies have found that they may help slow the development of cancers. Bitter gourds are pale green, with an irregular, warty surface. They're usually eaten while immature, sometimes after an initial blanching to remove some of the water-soluble cucurbitacins, and are either stuffed or combined with other ingredients, which moderate the bitterness. Mature fruits contain a red, sticky, sweet material that covers the seeds and is sometimes eaten. Bitter gourds have long been prized in Asia for a trait that's considered a defect in cuc.u.mbers, the presence of bitter cucurbitacins. There may be good reasons to cultivate a taste for cucurbitacins, because recent studies have found that they may help slow the development of cancers. Bitter gourds are pale green, with an irregular, warty surface. They're usually eaten while immature, sometimes after an initial blanching to remove some of the water-soluble cucurbitacins, and are either stuffed or combined with other ingredients, which moderate the bitterness. Mature fruits contain a red, sticky, sweet material that covers the seeds and is sometimes eaten.

Bottle Gourds Bottle gourds or calabashes are most often allowed to mature and then dried to make containers and ornaments. Italians call the immature fruits Bottle gourds or calabashes are most often allowed to mature and then dried to make containers and ornaments. Italians call the immature fruits cucuzze, cucuzze, and peel and cook them to produce a relatively bland version of a summer squash. and peel and cook them to produce a relatively bland version of a summer squash.

Luffa or Angled Gourds Luffa gourds, sometimes called Chinese okra, are elongated fruits with prominent ridges, and a mild taste and delicate texture when eaten immature. (A different species is used to make fibrous luffa "sponges"; true sponges are sea creatures.) Luffa gourds, sometimes called Chinese okra, are elongated fruits with prominent ridges, and a mild taste and delicate texture when eaten immature. (A different species is used to make fibrous luffa "sponges"; true sponges are sea creatures.) Winter or Wax or Fuzzy Melons Winter melons acc.u.mulate enough protective wax on their rinds that it can be sc.r.a.ped off and made into candles. On young fruits the wax-producing glands are more prominent than the wax itself, so they are known as hairy or fuzzy gourds or melons. These are cooked like summer squash, and their flesh becomes almost translucent. Winter melons keep well, and in Chinese cooking are used as an edible container for a festive soup. Winter melons acc.u.mulate enough protective wax on their rinds that it can be sc.r.a.ped off and made into candles. On young fruits the wax-producing glands are more prominent than the wax itself, so they are known as hairy or fuzzy gourds or melons. These are cooked like summer squash, and their flesh becomes almost translucent. Winter melons keep well, and in Chinese cooking are used as an edible container for a festive soup.

Chayote or Mirliton Chayote is the squash that seems least like a squash. It's the fruit of a Central American vine, and looks something like a large pear some 58 in/1220 cm long, with a single large seed at the center. Its flesh is finer-textured than the flesh of summer squashes, takes longer to cook, but is otherwise similar in its mild aroma and moist texture. The seed cavity is sometimes stuffed, and the seed sometimes eaten. Chayote is the squash that seems least like a squash. It's the fruit of a Central American vine, and looks something like a large pear some 58 in/1220 cm long, with a single large seed at the center. Its flesh is finer-textured than the flesh of summer squashes, takes longer to cook, but is otherwise similar in its mild aroma and moist texture. The seed cavity is sometimes stuffed, and the seed sometimes eaten.

The Bean Family: Fresh Beans and Peas Unlike most edible fruits, the fruits of the bean family were not designed to appeal to seed-dispersing animals. This group of plants is often called the legumes, legumes, "legume" being the name for their particular kind of fruit, a thin-walled pod, dry and brittle when mature, that encloses several seeds and disperses them by popping open when they're disturbed. It's in their dry form that we harvest most legume crops, since they can be stored indefinitely and are a concentrated source of nourishment (see chapter 9). Green beans and peas are immature pods and/or seeds, harvested before they begin to dry out, and are both very ancient and very recent foods. Early humans likely first ate the green pods and seeds, since dried seeds required cooking. However, the dried forms were so much more useful that varieties with pods specialized for eating green - with no tough inner "parchment" layer and reduced fiber throughout - have only been bred for a few hundred years. "legume" being the name for their particular kind of fruit, a thin-walled pod, dry and brittle when mature, that encloses several seeds and disperses them by popping open when they're disturbed. It's in their dry form that we harvest most legume crops, since they can be stored indefinitely and are a concentrated source of nourishment (see chapter 9). Green beans and peas are immature pods and/or seeds, harvested before they begin to dry out, and are both very ancient and very recent foods. Early humans likely first ate the green pods and seeds, since dried seeds required cooking. However, the dried forms were so much more useful that varieties with pods specialized for eating green - with no tough inner "parchment" layer and reduced fiber throughout - have only been bred for a few hundred years.

Green legume seeds are tasty and nourishing because they're collecting sugars, amino acids, and other nutrients from the rest of the plant, but haven't yet packed them all into compact and tasteless starch and proteins. The green pods are tasty and nourishing because they serve as a temporary storage depot for the seeds' supplies. The pods also generate their own sugars by photosynthesis, making use of carbon dioxide that its enclosed seeds give off as they grow. After they're harvested, the green pods continue to send sugars to the seeds, so they lose their sweetness. We eat the green seeds of many legumes, notably lima beans, fava beans, and soybeans (chapter9), but the pods of only a few: the common bean, long bean, and pea.

Green Beans Green beans come from a climbing plant native to Central America and the Andes region of northern South America. Though the peoples who domesticated them have probably always eaten some immature pods, the breeding of specialized vegetable bean varieties is less than 200 years old. There are now chlorophyll-free, yellowish "wax" varieties, and purple, chlorophyll-masking anthocyanin varieties that turn green when cooked (p. 281). The fibrous "strings" that normally join the two walls of the pod and are stripped away with the stem during preparation - hence the name "string beans" - were eliminated by a New York breeder in the late 19th century; these days only heirloom varieties tend to have strings. There are two general forms of green bean, one with round and thin pods, the other with flat and broad pods. Flat varieties have been found to have a more intense flavor. The flavor of cooked green beans is interestingly complex; it includes a number of sulfur and "green" compounds, but also the essence of fresh mushroom (octenol) and a flowery terpene (linalool). Green beans come from a climbing plant native to Central America and the Andes region of northern South America. Though the peoples who domesticated them have probably always eaten some immature pods, the breeding of specialized vegetable bean varieties is less than 200 years old. There are now chlorophyll-free, yellowish "wax" varieties, and purple, chlorophyll-masking anthocyanin varieties that turn green when cooked (p. 281). The fibrous "strings" that normally join the two walls of the pod and are stripped away with the stem during preparation - hence the name "string beans" - were eliminated by a New York breeder in the late 19th century; these days only heirloom varieties tend to have strings. There are two general forms of green bean, one with round and thin pods, the other with flat and broad pods. Flat varieties have been found to have a more intense flavor. The flavor of cooked green beans is interestingly complex; it includes a number of sulfur and "green" compounds, but also the essence of fresh mushroom (octenol) and a flowery terpene (linalool).

Good-quality green beans can be hard to find, because they're one of the most fragile vegetables. Their tissue is very active, so they quickly consume their sugars and lose sweetness even in cold storage. And thanks to their subtropical origins, they don't keep well at refrigerator temperatures; their cells become damaged and lose chlorophyll. Once they're picked, tender low-fiber varieties quickly become wrinkled and limp as they lose moisture and sugars. Commercial varieties have been bred with more fiber to help them survive shipping and marketing with a better shape.

Long or Yard-Long Beans Long beans, sometimes called asparagus beans, do sometimes reach a yard/meter in length. They're the thin, small-seeded pods of a subspecies of black-eyed pea, a native of Africa that was taken to Asia more than 2,000 years ago. Asian cultures already had a number of excellent seed legumes but no warm-climate vegetable legume, and it was India or China that developed the yard-long version of the black-eyed pea. These beans have a higher fiber content than common green beans and therefore a drier, firmer texture when cooked. They're also sensitive to chilling (they keep best in the cold but deteriorate quickly if then left at room temperature). Long beans, sometimes called asparagus beans, do sometimes reach a yard/meter in length. They're the thin, small-seeded pods of a subspecies of black-eyed pea, a native of Africa that was taken to Asia more than 2,000 years ago. Asian cultures already had a number of excellent seed legumes but no warm-climate vegetable legume, and it was India or China that developed the yard-long version of the black-eyed pea. These beans have a higher fiber content than common green beans and therefore a drier, firmer texture when cooked. They're also sensitive to chilling (they keep best in the cold but deteriorate quickly if then left at room temperature).

Peas Peas come from a climbing plant native to the Mediterranean area, and are eaten immature both in the pods and as sh.e.l.led green seeds (their tender shoots, stems, and leaves are also popular vegetables in Asia). Vegetable varieties of pea were first developed in the 17th century, beginning in Holland and then in England, and for a long time they remained luxury foods. There are several different types of pod peas, including the traditional English or European, round and thin-walled, the very recent "sugar snap" pea, round and thick-walled and quite crunchy, and "snow" or Asian peas, flat and broad, thin-walled, with small seeds. Peas and green capsic.u.m "bell peppers" contain similar and very potent "green" aroma compounds (isobutyl methoxypyrazines). Peas come from a climbing plant native to the Mediterranean area, and are eaten immature both in the pods and as sh.e.l.led green seeds (their tender shoots, stems, and leaves are also popular vegetables in Asia). Vegetable varieties of pea were first developed in the 17th century, beginning in Holland and then in England, and for a long time they remained luxury foods. There are several different types of pod peas, including the traditional English or European, round and thin-walled, the very recent "sugar snap" pea, round and thick-walled and quite crunchy, and "snow" or Asian peas, flat and broad, thin-walled, with small seeds. Peas and green capsic.u.m "bell peppers" contain similar and very potent "green" aroma compounds (isobutyl methoxypyrazines).

Some Vegetable Beans and Their Origins

Green bean

Phaseolus vulgaris Phaseolus vulgaris

Central America Central America

Lima bean

Phaseolus lunatus Phaseolus lunatus

South America South America

Green peas, sugar peas, snow peas, pea shoots

Pisum sativum Pisum sativum

Western Asia Western Asia

Fava bean

Vicia faba Vicia faba

Western Asia Western Asia

Long bean

Vigna unguiculata Vigna unguiculata

Africa Africa

Soybean

Glycine max Glycine max

East Asia East Asia

Winged, asparagus bean

Tetragonolobus purpureus Tetragonolobus purpureus

Africa Africa

Other Fruits Used as Vegetables Avocado The avocado tree The avocado tree Persea americana Persea americana is a native of Central America and a member of the laurel family, a relative of the bay laurel, California bay, and sa.s.safras. Like its relatives, it has aromatic leaves that are used as flavorings (p. 408). Avocado fruits are remarkable for containing little or no sugar or starch, and for being as much as 30% oil, the equivalent of well-marbled meat (but marbled with olive oil; avocado oil is largely monounsaturated). They apparently evolved to appeal to large animals with a high calorie requirement. The name comes from the Nahuatl word is a native of Central America and a member of the laurel family, a relative of the bay laurel, California bay, and sa.s.safras. Like its relatives, it has aromatic leaves that are used as flavorings (p. 408). Avocado fruits are remarkable for containing little or no sugar or starch, and for being as much as 30% oil, the equivalent of well-marbled meat (but marbled with olive oil; avocado oil is largely monounsaturated). They apparently evolved to appeal to large animals with a high calorie requirement. The name comes from the Nahuatl word ahuacatl, ahuacatl, which was apparently inspired by the fruit's pear-like shape and irregular surface; it means "t.e.s.t.i.c.l.e." which was apparently inspired by the fruit's pear-like shape and irregular surface; it means "t.e.s.t.i.c.l.e."

There are three geographical groups of avocado. The Mexican group evolved in relatively cool subtropical highlands, so the trees are the most cold-tolerant; they produce small and smooth-fleshed fruit that are high in oil and can take relatively low storage temperatures, around 40F/4C. The lowland group evolved on the semitropical west coast of Guatemala and are the least cold-tolerant; their fruits tend to be large and coa.r.s.e-fleshed and suffer chilling injury below about 54F/12C. And the Guatemalan group, from the semitropical highlands, is intermediate in most respects; the flesh of its fruits is least fibrous and the proportion of seed the lowest. In the United States, where most avocados are grown in southern California, commercial varieties are of mixed background. The most common variety, and one of the best, is the black, pebbly-skinned Ha.s.s, which is mainly Guatemalan. The smooth, green-skinned Fuerte, Pinkerton, and Reed are also relatively rich, while green Bacon and Zutano, and Florida's Booth and Lula, have more lowland ancestry, tend to remain firm, and have half or less the fat content of the Ha.s.s avocado.

Avocados don't begin to ripen until after they've been picked, so they're stored on the tree. All types ripen from the broad end toward the stem within about a week of harvest, and develop the best quality at temperatures between 6075F/1524C. Ripening can be accelerated by enclosing the fruit in a paper bag with an ethylene-emitting banana. If these warm-climate fruits are refrigerated while unripe, their cellular machinery is damaged and they will never ripen; once ripe, however, they can be refrigerated for several days and retain their quality. The aroma of avocado comes mainly from a group of mildly spicy terpenes including woody caryophyllene, as well as unusual 10-and 7-carbon fragments of fatty acids.