Tropical Fruits (including "nuts")

I. Tropical -tropical regions do not experience frosts, but there may be wet-dry seasonality or diurnal temperature fluctuations

A. most tropical fruits come from woody perennials but humans plant some as annuals, e.g. tomato, melon, pepper

B. if woody perennials can't tolerate freezing temperatures, at least for very long, so limits where grown

C. most tropical fruits are readily perishable so either gathered in the wild or grown on limited basis, and consumed locally

D. special shipping and anti- spoilage techniques have allowed some tropical fruits to become more widely distributed, e.g. bananas

E. see table 4.2. for annual world production

II. Citrus fruits - genus Citrus (family Rutaceae)

A. broad leaved evergreen trees probably originated in southeast Asia

B. fruit a hesperidium, a berry with a leathery skin filled with aromatic oils

1. contain high proportion of citric acid giving them their characteristic astringent odor and flavor, good sources of vitamin C

2. endocarp, which is eaten, is composed of highly modified hairs or sacs which contain a solution of sugars and acids

3. fruit color only develops in cool temperatures which promote formation of carotene and breakdown of chlorophyll

a. in tropical regions they remain green, e.g. lime plant is extremely sensitive to cool conditions, thus it is usually never exposed to cool enough conditions to develop a color. If left in a cool place over winter, the fruits will change to yellow 

b. producers sometimes spray with ethylene to induce color change

C. can not tolerate freezing except for a very brief period

D. until recently grown from seeds but more popular seedless varieties are vegetatively propagated

E. sweet orange C. sinensis is most widely grown fruit in the world

F. "golden apples" of Hesperides, seeds given to Hera when she married Zeus and planted in the garden of Hesperides, hence the fruit name hesperidium

G. vitamin C prevented scurvy so fruits taken around the world by sailors. Limey was nickname for English sailors who were ordered to drink lime juice daily 

H. oranges first introduced to US in Florida by Spanish in 1565

I. three types of sweet oranges

1. blood - which have red streaks and patches of red in pulp, not very popular in US

2. normal - Valencia is most commonly grown

a. introduced to California and Florida in 1870's from the Azores

b. largest crop in Florida and used primarily for juice

3. navel - derived from a spontaneous mutation that occurred in Brazil about 1820

a. flowers produce an abnormal small ovary on top of the regular ovary

b. when fruit matures a "twin" fruit, with a smaller orange embedded in the outer fruit, develops. From the outside, the smaller, undeveloped twin leaves a formation at the top of the fruit, looking similar to the human navel.

c. navel oranges are almost always seedless so propagated vegetatively

d. navel oranges tend to be bigger and since they are seedless and easy to peel, they are the principle "eating" orange

e. primary orange grown in California

J. Other citrus fruits

1. lemon, lime, citron, bitter orange, grapefruit

2. lemon juice and flavor widely for flavoring, scents, and cleaning products

3. grapefruit arose as a spontaneous hybrid between sweet orange and pummelo about 1750 in Barbados

a. commercial production of grapefruit in US began in 1880, a pink mutation arose spontaneously after that

III. Squashes and their relatives (family Cucurbitaceae)

A. monoecious, annual vines, fruit a pepo, derived from an inferior ovary and hard rind (store well)

B. squashes, genus Cucurbita, native to new world (cultivated at least 12,000 yrs), important staple crop 

1. pumpkins, gourds, squash

2. luffa gourd is eaten young but as it mature the fruits become tough and fibrous

3. gourds also hollowed out and used as containers

C. melons native to Africa and Asia, more dessert fruits

D.  cucumbers important sources of water, pickles

1. watermelon, cantaloupe, honeydew, cucumber

2. pickling - immersing in brine or vinegar solution one of first methods of preservation 

IV. Fruits if the Solanaceae (nightshade family)

A. Tomato - Lycoperscion (Solanum) esculentum (juicy wolf peach) - Germans believed use to evoke werewolves

1. most important "vegetable" crop in the US

2. originated in western South America, many believe Thomas Jefferson introduced to US

a. wild relatives outbreeding perennials but now self-pollinating annuals

3. name comes from Mayan xtomatl or tomatl called tomate by Spanish

4. slow to gain acceptance because thought to be poisonous because leaves are poisonous

5. U.S. tariff laws imposed a duty on vegetables but not on fruits which caused a tax dispute with the port of NY. In 1893 Supreme Court declared tomato a vegetable

6. extensively in Mediterranean and Middle Eastern cuisines, especially Italian

a. acidic properties to bring out other flavors, same acidity makes tomatoes easy to preserve in home canning as tomato sauce or paste

b. tomato juice often canned and sold as a beverage

c. unripe green tomatoes can also be used to make salsa, be breaded and fried, or pickled

d. often picked unripe, and ripened in storage with ethylene. These  keep longer, but have poorer flavor and a mealier, starchier texture than tomatoes ripened on the vine

B. Sweet peppers (Capsicum)

1. go back at least 7,000 years in Mexico

2. most peppers grown in US are sweet and bell peppers 

3. hot peppers discussed later

V. Coconuts (Cocos nucifera)

A. one of most versatile plants - food,  drink, clothing, fiber, building materials

B. monoecious monocots with a tree-like trunk composed of sheathing leaf bases

C. origins controversial but probably Indo-Pacific region

1. fruits light and buoyant and spread significant distances by marine currents

2. thrive on sandy soils and highly tolerant of salinity, prefers areas with abundant sunlight and regular rainfall, which makes colonizing shorelines of the tropics relatively straight-forward

3. need high humidity (70–80%) for optimum growth, which is why they are rarely seen in areas with low humidity

D. probably first domesticated in Malaysia, now planted in mild climates nearly everywhere

E. fruit formed from a flower with three carpels (eyes), only one of which develops

1. coconut milk = liquid endosperm containing many free nuclei from green coconuts 

2. as endosperm matures walls form around the nuclei forming solid tissue "meat" (copra)

VI.  Dates - genus Phoenix

A. important fruit since Biblical times

B. gathered as food by nomads for thousands of years

C. considered "tree of life" by Bedouins - presence indicated water, highly nutritious, 60-70% sugar and 5% protein

D. plants are dioecious but by 2300 BC people learned to dust the pollen on the female flowers

E. Muslims believe date palm was made from the dust left after God made Adam

VII. Pineapple genus Ananas (Bromeliaceae)

A. native to new world

B. Columbus described as looking like pine cones, hence the common name

C. multiple fruit (100 - 200 flowers) consisting of fleshy inflorescence axis

D. seedless domesticated variety is parthenocarpic and fruiting stimulated by spraying with hormones

E. propagation vegetatively

F. cultivation spread around the world by 15th century, introduced o Hawaii by Dole in early 19th century

1. major crops now from South East Asia and Africa

2. easily canned but bromelain, a proteolytic enzyme, prevents use in many deserts, e.g. gelatins

3. juice used as a meat tenderizer

4. fresh pineapple is often expensive, delicate and difficult to ship, will not ripen once harvested, so must be harvested ripe and brought to the consumer without delay

5. juice has been fermented into an alcoholic beverage called pineapple wine, most commonly found in Hawaii

VIII. Banana genus Musa - one of most widely consumed foods in the world

A. native to SE Asia, cultivated perhaps 10, 000 years ago in New Guinean highlands

B. first in written history in Buddhist texts in 600 BC

1. Alexander the Great encountered in India in 327 BC

2.  first plantation in China in 200 AD

3. in 650 Islamic conquerors brought the banana to Palestine. Arab merchants eventually spread bananas over much of Africa

4. in 1502 Portuguese colonists started the first banana plantations in the Caribbean and in Central America

5. 1522 planted on Canary Islands as food  for slaves sent to New World

C. starting in 1899 United Fruit Company controlled banana (and coffee) production in Central America, in 1930s bananas and coffee made up as much as 75 percent of the region's exports. For decades the UFC owned huge tracts of land and controlled thousands of workers throughout Central and South America. The term "banana republic" has been broadly applied to the countries in the region, but from a strict economic perspective only Costa Rica, Honduras, and Panama were actual "banana republics" – countries with economies dominated by the banana trade

D. whole cargoes of bananas were often ruined because carbon dioxide and ethylene produced by bruising could spoil entire shipments

1. now only perfect green bananas shipped and kept at 50 degrees F and 90 % humidity

2. ethylene gas may be used to hasten ripening later on

E. wild bananas have thick peel, many large seeds and little pulp

1. domesticated bananas are triploid from hybridization and polyploid between two wild species, therefore sterile

2. propagated from corms, suckers or almost any vegetative part

F. plants are annual tree like herbs with lateral suckers produced at the base

G. flowers borne on large pendant inflorescences with female flowers at the base and male flowers toward the tip

1. plants flower 2-6 months after shoot elongation

2. female flowers in whorls of 12-20, each whorl produces a bunch or "hand" of fruits

3. generally harvested manually by one person (a cutter) cutting the stem while the entire stem of fruits, weighing as much as 100 lbs., is gently laid on the back of another (backer)

4. after harvesting the cutter decapitates the plant and cuts up the leaves

5. plants may be replanted each year but often a sucker form the previous plat is allowed to grow up. this can be done for 5-25 years

6. bananas may yield as much carbohydrate per acre as potatoes

H. bananas contain 74% water, 23% carbohydrates, 1% proteins, 0.5% fat, and 2.6% fiber. In an unripe banana the carbohydrates are mostly starches. In the process of ripening the starches are converted to sugars; a fully ripe banana has only 1-2% starch

1. besides being a good source of energy, bananas are rich in potassium and hence highly recommended for patients suffering from high blood pressure, also good food for athletes

I. in some parts of South-East Asia "banana" is a derogatory term for a person of Chinese descent who does not know much about Chinese Culture and speaks English, "yellow outside, white inside"

IX. Figs genus Ficus

A. about 800 species but only Ficus carica is commercially grown for fruits

B. native to Mediterranean region, cultivated for perhaps 5,000 years

C. inflorescence is a syconium - a bulb shaped structure containing thousands of tiny flowers

1. most have intricate wasp pollination 

2. females lay eggs inside inflorescence, inside developing fruit females mate with males, fly off and lay eggs in another inflorescence

3. some figs varieties (Smyrna, most popular) produce only female flowers so must be pollinated from male flowers on another tree. Failure to recognize this resulted in fruitless trees when introduced in the New World 

4. Buddhist and Hindu texts refer to "seeking flowers in a fig tree" to indicate something that is pointless or impossible

D. figs have tremendous vegetative reproductive abilities and are considered a serous invasive species in California

X. Avocado genus Persea

A. evergreen trees native to Central America and Mexico, cultivated for perhaps 9,000 years, no longer wild

B. fruit is a berry or drupe

1. fruit is high in fats and calories, highest caloric value of any fruit

2. difficult to explain

3. some hypothesize adapted for a now extinct mammal

C. fruits do not ripen on tree must fall off or be hand picked, once hand picked allowed to rest for 25 hours and then treated with ethylene to ripen

D. in US 95% of avocados grown in California, with 80% in San Diego County

1. Hass (commonly misspelled Haas) is most common cultivar

Tropical "nuts"

I. Macadamia genus Macadamia

A. true nuts of Proteaceae, naive to Australia

B. commercially produced mostly in Hawaii

C. shells are extremely hard and even dried require 300 lbs per square inch to crack

II. Cashew genus Anacardium of Anacardiaceae - poison oak family 

A. native to northeast South America

B. most parts are toxic, skin irritant toxin urushiol (also found in poison oak)

C. the "fruit" of the cashew is a pear-shaped pseudofruit or false fruit that develops from the receptacle of the cashew flower

1. the cashew apple ripens into a yellow and/or red structure about the size of a plum or pear

2. cashew apple can be eaten raw or used in the production of jam, or various beverages, distilled into liquor or consumed diluted and sugared as a refreshing drink. The cashew apple contains much tannin and is very perishable so in many areas it thrown away after removal of the cashew nut

3. the "nut" is the embryo borne inside a drupe

III. Brazil "nuts" genus Bertholletia

A. native to South American tropics

B. "nuts" are large hard coated seeds contained in large capsule weighing up to 5 lbs.

C. 12- 24 seeds are formed in each capsule and up to 300 capsules may be produced per tree

D. nearly all are harvested from wild trees, a rarity