Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

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regulators. The callus phase provides a possible

source of induced variation and novel genetic recom-

binations in the form of somaclonal variation. This

can occur spontaneously or can be induced by the

application of mutagens such as g-irradiation to the

initial material. While, in the context of maintenance

of a germplasm collection, this type of variation is

highly undesirable, in a germplasm enhancement con-

text, there are precedents for its use. These include

inducing variation and screening regenerant material

of peach germplasm for bacterial resistance, and the

production of dwarf cherry rootstocks by applying

either g-irradiation or the chemical mutagenizing

agent, colchicine, to in vitro cultures to generate

novel variants.

0031 Other techniques Several other plant tissue culture-

based methodologies are available for the improve-

ment and maintenance of fruit germplasm. These

include:

0032 Somatic embryogenesis, i.e., the initiation and de-

velopment of embryos from vegetative cells. This

approach has been demonstrated in both grape

and apple.

0033 Gametic embryogenesis, i.e., the regeneration of

plants from cells derived from the gametophytic

cycle of the plant, usually pollen or microspores.

This technique is a potentially powerful breeding

tool, as plants derived from this system would be

haploid (or half the native chromosome number),

and subsequent chromosome doubling would pro-

duce homozygous lines. This represents a consid-

erable time-saving from the many generations of

inbreeding required to achieve this by conven-

tional crossing and selection methodology. The

method has been demonstrated in Vitis, Prunus,

and Pyrus species, and very recent work has

successfully applied both anther culture and

microspore systems to apple.

0034 Cell-suspension cultures can be established from

calluses of plants maintained in liquid medium in

various forms of rotating vessel. These systems

offer great potential for the production of specific

compounds such as specific flavorings and color-

ings for use in the food-processing industry. Of

even higher value is the use of such cell-culture

systems for the production of secondary metabol-

ites and pharmaceuticals derived from selected

plant cells.

0035 Protoplasts Protoplasts (individual plant cells that

have been isolated and had their cell wall removed

enzymatically) offer an alternative method for genetic

manipulation. Earlier work in fruit crops was limited

to Vitis, Prunus, Pyrus, and Malus, but recent work

has been described in a wide range of soft fruit species

such as Ribes and Rubus. Possibly the most signifi-

cant application of protoplast technology in plant

germplasm improvement is in the area of protoplast

fusion (somatic hybridization) where hybrid con-

structions can be made between taxonomically dis-

tant species beyond the normal limits of sexual

compatibility, and cells with novel nuclear and cyto-

plasmic construction created. During the last 15

years, numerous reports of successful somatic hybrid-

ization at the intraspecific, interspecific, and even

intergeneric levels have been published. Although

the applications of the techniques in fruit breeding

to date have been more limited than in other species,

reports of fusions between Rubus species and be-

tween Pyrus and Prunus (cherry) protoplasts have

been made. The potential for generating novel genetic

combinations remains high, however, with useful

targets including the introgression of disease resist-

ance from incompatible wild species into cultivated

lines. The use of protoplast fusion in creating inter-

specific Malus hybrids is considered by some apple

breeders as an important prospect for future develop-

ment of apple cultivars.

Gene Transfer

0036Although protoplast fusion enables the potential for

whole or partial genome transfer between plants, a

more targeted approach for the introduction of

known genes or nucleotide sequences into plants is

mediated by the application of a range of methods,

generically described as transformation technologies.

0037Agrobacterium-mediated transformation The most

widely used method for the transformation of higher

plants is by utilization of the natural gene transfer

characteristics of Agrobacterium. Agrobacterium

tumefaciens is a naturally occurring soil bacterium

that readily infects a large number of dicotyledonous

plants. It is unique in that the bacterium integrates its

own DNA into the plant genome. Since the first

report of the successful transformation of a plant

in 1983, over 120 plant species have since been

transformed, including a significant number of fruit

species. These include Malus, Fragaria,andVitis

species. Transgenic plants of Malus have been

shown to display stable patterns of expression and

Mendelian segregation of transgenes. Modern vectors

for transformation have been refined to minimize the

amount of foreign DNA incorporated into the recipi-

ent plant. Many of the most desirable traits for im-

provement in fruit crops such as increased yield,

better growth habit, and low-temperature hardiness

are polygenic (i.e., controlled by more than one gene)

and as such, owing to the limitations in gene transfer,

2778 FRUITS OF TEMPERATE CLIMATES/Improvement and Maintenance of Fruit Germplasm

may not be readily improved by transformation tech-

nologies. However, single gene traits can be readily

introduced into fruit plant species. Examples include:

0038 Insect resistance: gene transfer programs have been

reported for the insertion of the gene sequence

coding for the expression of Bacillus thuringiensis

(Bt) toxin into Malus species. Improved levels of

pest resistance have been reported in several stud-

ies using this strategy. In addition, the cowpea

protease trypsin inhibitor (CpTi) gene, encoding

for an antimetabolite to a wide range of lepidop-

teran and coleopteran pests, has been inserted into

several fruit species, and the results of field trials of

such material have been promising.

0039 Virus resistance: the introduction into the plant of

part of the nucleotide sequence of the viral

genome, e.g., coat-protein sequence has been dem-

onstrated to confer resistance to viral infection.

The mechanism is thought to be in much the

same way as field-grown plants may be protected

against a second viral infection through the cross-

protection response afforded by an earlier viral

attack, as demonstrated for tobacco mosaic

virus. The expression of coat protein genes inte-

grated into the plant via transformation has been

shown to result in an elevated degree of protection

against viral infection in tomato and other species.

The introduction of an Arabis mosaic virus coat-

protein gene into certain soft fruit species is

currently being undertaken, and reports of the

implementation of pathogen-derived resistance to

plum-pox virus have also been made.

0040 Fruit quality: a range of the component factors

associated with fruit quality, such as sugar content

and various ripening processes have been the sub-

ject of a number of recent gene-transfer research

programs.

In recent years, not only has the host range of species

amenable to Agrobacterium-mediated transform-

ation been widened, but also alternative systems for

gene delivery and transfer have been developed.

These include the use of a helium-powered biolistic

gun to propel plasmid DNA on gold bullets into plant

cells. This technique is widely used for recalcitrant

plant species and assists in overcoming problems both

with Agrobacterium infectivity and in the necessity

of efficient tissue regeneration systems. The main

problems precluding the uptake on a wide scale of

transgenic crops are probably not technology-based

but related to the issues of public acceptance of trans-

genic products. The scope and potential of transgenic

crop technologies are extremely wide, but each case

must be considered on its merits.

Molecular Markers

0041Methods for the identification, characterization, and

quantification of genetic variability have enormous

potential application in germplasm enhancement pro-

grams and can, if applied successfully, offer great

timesaving benefits. Previously, the use of isozyme

analysis in fruit for genotype identification has

proved successful in species such as apple, pear, and

cherry, but less successful in species where poly-

morphism is lower. Isozymes tend to have relatively

low genomic coverage and do not always provide

sufficient polymorphism to prove useful in genetic

analysis. However, the last few years have witnessed

a dramatic rise in the sophistication and applicability

of a range of DNA-based molecular markers.

0042The rapid development of genomics technologies,

particularly those based on the polymerase chain re-

action, has enabled significant progress to be made

recently in both genetic mapping and the identifica-

tion of diagnostic molecular markers that can facili-

tate breeding and selection of specific characters. The

marker systems of choice are now amplified fragment

length polymorphisms (AFLPs), simple sequence

repeats (SSRs) and single nucleotide polymorphisms

(SNPs). Major advances have been made in the map-

ping of specific fruit genomes, notably apple but also

Rubus, Ribes and Vaccinium, and in the development

of markers linked to both single gene traits, such as

some pest resistances, and more complex quantitative

traits, particularly those relating to fruit quality. The

use of these markers in fruit breeding programmes

will increase in future and should greatly assist the

speed, focus and productivity of fruit germplasm

improvement.

See also: Fruits of Temperate Climates: Commercial and

Dietary Importance; Fruits of the Ericacae; Factors

Affecting Quality; Improvement and Maintenance of Fruit

Germplasm; Fruits of Tropical Climates: Commercial

and Dietary Importance; Fruits of the Sapindaceae; Fruits

of the Sapotaceae; Lesser-known Fruits of Africa; Fruits of

Central and South America; Lesser-known Fruits of Asia;

Nucleic Acids: Physiology

Further Reading

Abbott AJ and Atkin RK (eds) (1987) Improving Vegeta-

tively Propagated Crops. London: Academic Press.

Anon. (1998) The State of the World’s Plant Genetic

Resources for Food and Agriculture. Rome: Food and

Agriculture Organization of the United Nations.

Benson EE (ed.) (1999) Plant Conservation Biotechnology.

London: Taylor & Francis.

Eck P (1990) The American Cranberry. New Brunswick,

NJ: Rutgers University Press.

FRUITS OF TEMPERATE CLIMATES/Improvement and Maintenance of Fruit Germplasm 2779

Janick J and Moore JN (eds) (1996) Fruit Breeding (3.

vols.). New York: John Wiley.

Millam S and Spoor W (1999) Biotechnology and crop

improvement. In: Simmonds NW and Smartt J (eds)

PrinciplesofCrop Improvement, 2nd edn, pp. 285–306.

London: Blackwell Science.

Moore JN and Janick J (eds) (1983) Methods in Fruit

Breeding. W. Lafayette, In: Purdue University Press.

Roache FA (1985) Cultivated Fruits of Britain. Their Origin

and History. Oxford: Blackwell Scientific.

Smartt J and Simmonds NW (1995) Evolution of Crop

Plants, 2nd edn. Harlow, UK: Longmans.

Stalker HT and Chapman C (eds) (1989) Scientific Manage-

ment of Germplasm: Characterization, Evaluation and

Enhancement. Rome: International Board for Plant

Genetic Resources.

FRUITS OF TROPICAL CLIMATES

Contents

Commercial and Dietary Importance

Fruits of the Sapindaceae

Fruits of the Sapotaceae

Lesser-known Fruits of Africa

Fruits of Central and South America

Lesser-known Fruits of Asia

Commercial and Dietary

Importance

S J R Underhill, Horticulture Postharvest Group,

Hamilton, Queensland, Australia

This article is reproduced from Encyclopaedia of Food Science,

Background

0001 Tropical fruit are a botanically diverse group of fruit

indigenous to tropical regions. Their representatives

come from numerous families, including Anacardia-

ceae (mango, hog plum, imbu), Sapindaceae (rambu-

tan, taun, lychee, longan), Passifloraceae (passion

fruit), Bromeliaceae (pineapple) and Annonaceae

(custard apple, soursop, sugar apple). Traditionally,

tropical fruit were consumed locally, either grown in

a subsistence-style agricultural structure or gathered

from the wild. (See Mangoes; Pineapples.)

0002 Increasing production, a more efficient transpor-

tation system, and refrigerated storage have led to

increased global consumption in recent years. Con-

siderable quantities of tropical fruit are now exported

each year to European, Japanese, and American

markets. The vast majority of this production is con-

sumed fresh, although processing industries have also

been established. In an increasingly health-conscious

population, tropical fruit are seen as an appropriate

source of nutrition, added variety and exotic appeal.

Production

0003Tropical fruit production is a large, rapidly expanding

industry (Table 1). Bananas and pineapples, particu-

larly from the Philippines, China, Mexico, and Brazil,

represent the majority of world trade in tropical fruit.

Collectively, these countries produced over 12 10

of bananas and 3 10

t of pineapples in 1988. Al-

though world production figures continue to rise,

other fruit, such as mango, papaya, and lychee, are

becoming increasingly popular. The subtropical

regions of the world, particularly Colombia, Florida,

tbl0001Table 1 Tropical fruit production for fresh consumption in

selected growing regions in 1988

Banana

(10

Mango

(10

Pineapple

(10

Papaya

(10

Lychee

(10

Australia 159 12 154 2

Bangladesh 690 160 150

Brazil 5139 400 1016 1600

China 2350 430 95 62

Colombia 1300 230 44

India 9450 790 339 92

Indonesia 1860 410 350 270

Kenya 148 191

Malaysia 490 199

Mexico 1080 780 293 630

Philippines 3645 378 2250

Thailand 1606 1771 84

From Anonymous (1989) Fruit and Tropical Product. London:

Commonwealth Secretariat Publications.

2780 FRUITS OF TROPICAL CLIMATES/Commercial and Dietary Importance

South Africa, Vietnam, Panama, and Mexico, have

rapidly expanded their tropical fruit production over

the last 20 years. In many of these countries, tropical

fruit have become an important source of export

revenue. (See Bananas and Plantains.)

0004 Historically, fruit production was highly regional-

ized within the tropics. However, much of the current

horticultural production is now removed from the

place of origin of the particular species. For example,

91 860 t of lychee were produced by India in 1987,

substantially more than the fruit’s native China pro-

duction of 61 820 t. Granadilla (Passiflora quadran-

gularis), native to the Americas, is now widely grown

throughout the world.

History

0005 The increasing horticultural status of tropical fruit

comes from their progressive importation into the

more temperate regions of the world. This ‘Western-

ization’ of tropical fruit has become prominent over

the last 100 years. Its origins extend back to the early

1550s with the transportation of pineapples from

South America, and the shipment of bananas across

the Caribbean in the 1770s. Many of these journeys

have been immortalized in the history books: the

expedition sponsored by King George III and Sir

Joseph Banks to transport breadfruit (Artocarpus alti-

lis) to the West Indies, and the ensuing ‘mutiny on the

Bounty,’ is a good example. Although this early

distribution was fundamental to the subsequent de-

velopment of tropical horticultural production, most

of these fruit were already widely used by the local

population. With transportation by air, it is now pos-

sible to move large quantities of tropical fruit any-

where in the world in a matter of days. Increased

production and better cultivars will further aid the

development of the fresh fruit industries in the future.

Economic Status

0006 To assess their commercial importance, tropical fruits

need to be divided into three arbitrary groups. Thus,

familiar, well-established fruit, such as banana (Musa

spp.) and pineapple, represent the majority of current

tropical fruit production (Tables 1 and 2). In 1987,

the European Community (EC) imported 238 936 t of

pineapples, with France (66 304 t), Italy (43 644 t),

and Germany (38 877 t) the main markets. Recent

importation figures for the USA (1988) are around

100 000 t of pineapples, 2 873 000 t of banana, and

108 000 t of plantains.

0007 Mango and papaya dominate the second group and

are characterized by rapid industry growth. In the

5 years from 1983 to 1987, imports of papaya into

the EEC rose from 1358 to 5074 t. The UK imported

1556 t of papaya in 1989 alone. These fruit are be-

coming more widely grown in subtropical regions,

such as Jamaica, India, Mexico, Puerto Rico, Israel,

the USA and Brazil. (See Papayas.)

0008The final group is made up of the lesser-known

exotic fruits, such as lychee, durian (Durio zibethi-

nus), rambutan (Nephelium lappaceum), pulasan

(N. mutabile), mangosteen (Garcinia mangostana

L.), black sapote (Diospyros digyna), jackfruit (Arto-

carpus heterophyllus Lam.), carambola (Averrhoa ca-

rambola), and abiu (Pouteria caimito). These fruit are

still relatively unknown in the northern hemisphere,

with total imports into the EC around 9000 t in 1988.

0009Tropical fruit not only represent an important

source of income for many countries but also have a

valuable social and cultural significance. It is from

their diversity of uses that the true socioeconomic

value of these fruits becomes evident.

Fresh Consumption

0010The consumption of tropical fruit is greatest in their

place of origin. The average Western European and

Northern American consumes about 10 kg of citrus

and banana per year. In parts of Africa, plantains may

be consumed at the rate of 400 kg per person per year.

Similar consumption rates exist for breadfruit in

the West Indies. In their place of origin, these fruit

represent a cheap and relatively plentiful food source.

Historically, much of this production was easily

tbl0002Table 2 Tropical fruit imported by Japan in 1988

Fruit Quantity (t) Exporter

Banana 760 409 Philippines 79%, Taiwan 11%,

Ecuador 9%, Colombia 1%

(China and Malaysia <1%)

Pineapple 138 156 Philippines 94%, Taiwan 5%

(Thailand, Indonesia, Hawaii,

China, Malaysia and Australia

<1 % )

Papaya 5 240 Hawaii 100% (Fiji <1%)

Mango 5 291 Philippines 79%, Mexico 18%,

Thailand 1%, Taiwan 1%

(Colombia, Fiji, Venezuela

and USA <1%)

Lychee 1 149 Taiwan 100%

Durian 104 Thailand 95%, Indonesia 3%,

Philippines 2% (Singapore and

Sri Lanka <1%)

Passion fruit 15 New Zealand 79%, USA 19%,

Colombia 2% (Fiji <1%)

Pitaya

(Hylocereus

undatus B.)

22 Colombia 100% (Mexico <1%)

From Kitagawa H, Matsui T, Kawada K and Agravante JU (1990) Japan as a

market of tropical fruit. Acta Horticultural 269: 41–45.

FRUITS OF TROPICAL CLIMATES/Commercial and Dietary Importance 2781

obtained with relatively little horticultural input.

Owing to this large local consumption, it is difficult

to assess accurately the true economic value for many

tropical fruit, particularly the more exotic types. Pro-

duction is never fully documented in official records,

and in many cases, import–export quantities of trop-

ical fruit are unknown. In Java, for example, 90% of

fruit consumed is grown in the home garden. The

heavy reliance on subsistence farming makes assess-

ment even more difficult. (See Citrus Fruits: Types on

the Market.)

0011 The processing of tropical fruit has also developed

into large industries (Table 3). Fruit have been canned,

dried, frozen, or juiced, and marketed either as an

individual product or in combination with other fruit

types. Canned pineapple is probably the most obvious

example. In 1990, over 920 000 t of canned pineapple

were produced worldwide. Many of the South-east

Asian countries, particularly Thailand, have already

developed significant processing industries specializ-

ing in the exotic tropicals such as canned lychee

and longan, dried mango, and frozen durian. Japan,

the USA, and Europe are showing increasing interest

in the processing of these more exotic fruit types,

particularly mango, passion fruit, and soursop.

Although quality is currently highly variable, it is

through these products that many people first experi-

ence tropical fruit.

Other Uses

0012 The commercial value of tropical fruit is generally

equated to their consumption as either a fresh

or cooked product. There is, however, a strong de-

pendence on products derived from these fruits.

In Africa, large quantities of a weak beer are

brewed from banana, representing an important

nutritional source. Cashew apple (Anacardium

occidentale), soursop (Annona muricata), and tamar-

ind (Tamarindus indica) are all important sources

of alcoholic and nonalcoholic beverages in many

countries.

0013Tropical fruits have been extensively adopted in local

medicine and religious practices. Bananas are widely

favored as a treatment for stomach complaints, par-

ticularly ulcers. Tamarind extract is used as the basis of

laxatives for bile disorders and in the treatment of

fevers. For the more indulgent, carambola has been

suggested in the treatment of hangovers.

0014Much of the medicinal use of tropical fruits is

restricted to folk medicine. There are, however,

reports in Western medicine of tropical fruit being

successfully administered. In 1977, a London hospital

reported the control of a postoperative infection in a

kidney transplant patient using strips of papaya flesh,

where conventional techniques were ineffective.

The strong anti-Gram-negative bacterial response of

papaya has now been widely documented. Much can

be learnt from local folk medicine, and it is likely that

with more research, other beneficial chemical com-

pounds will be isolated.

0015Tropical fruit also have a strong cultural signifi-

cance. In the Hindu religion, the banana plant is

considered a symbol of fertility, and fruit are placed

at the doorstep of the dwelling of newly married

couples. In South China, bananas are also sometimes

planted in the corner of rice fields as a symbol of

prosperity for the coming harvest.

Toxicity

0016Many tropical fruit contain potentially toxic com-

ponents. In most cases, these are restricted to the

nonedible portions – mainly the seed, peel, and

latex – and do not pose any real health risk. Many

of these products have been widely utilized by the

native population in local medicine. Durian seeds

are known to induce breathing problems, and an

extract made from langsat (Lansium domesticum)

skin has been used as a hunting poison. The real

danger occurs when these so-called nonedible com-

ponents are inadvertently consumed along with the

pulp. For example, jaboticaba (Myrciaria cauliflora)

skin, which has carcinogenic properties when

ingested over a long period, may be accidentally con-

sumed in the same manner as one would eat grape

skins. (See Carcinogens: Carcinogenic Substances in

Food: Mechanisms.)

0017Where ingestion of the pulp itself causes problems,

it is usually attributed to the consumption of large

quantities. A mild degree of toxicity in mamey fruit

(Mammea americana) has been known to occur. It has

been reported to cause digestive problems in the

Caribbean Islands, and extracts fed to dogs have

proven fatal. The akee (Blighia sapida) and sunsapote

(Licania platypus) are other such fruit with known

toxic properties.

tbl0003 Table 3 Production of processed pineapple from selected

countries

Canned (10

t) Juiced (10

Australia 40 29

Malaysia 46 1

Philippines 216 83

South Africa 63 10

Thailand 380 44

USA 133

From Anonymous (1989) Fruit and Tropical Product. London:

Commonwealth Secretariat Publications.

2782 FRUITS OF TROPICAL CLIMATES/Commercial and Dietary Importance

Limitations to Economic Development

Cultivar Selection

0018 The commercialization of tropical fruit has been

limited in the past by little plant breeding and the

existence of a wide range of cultivar types. Mango,

for example, is one of 14 species of the genus Mangi-

fera, all of which produce edible fruit. Within the

species M. indica, there are numerous distinct

cultivars. In India alone, there are over 500 named

cultivars. Each cultivar may differ in fruit quality,

storage life, environmental growth requirements,

and disease and insect susceptibility.

0019 Cultivar selection and breeding are essential if the

full potential of tropical fruit is to be achieved.

Tropical tree fruit breeding is presently both labor-

intensive and time-consuming. These limitations may

be reduced with the recent advancements in plant

biotechnology.

Storage

0020 As more tropical fruit are transported around the

world, there is an increasing reliance on storage.

Unlike temperate fruit, most tropical fruits are diffi-

cult to store. They deteriorate rapidly after harvest

and are highly susceptible to pathogen attack. If fruit

are stored under ambient conditions, they become

inedible within days. Even under optimal conditions,

storage life is rarely longer than a few weeks. In the

past, this has tended to limit the commercial success

of many tropical fruit. In the production areas, rapid

local consumption tends to reduce losses, but signifi-

cant postharvest spoilage still occurs. The develop-

ment of adequate storage and handling technology is

necessary if the tropical fruit industries are to con-

tinue to expand. Although considerable postharvest

research is under way worldwide, great reliance is still

placed on expensive air transport to reduce transpor-

tation time. (See Spoilage: Bacterial Spoilage; Storage

Stability: Mechanisms of Degradation.)

0021 The accessibility of fruit is also an important criter-

ion in economic success. Many tropical fruits fail to

establish a market niche because of irregular, highly

seasonal supply, compounded by a short shelf-life.

These problems will become less significant as more

countries produce tropical fruit and our postharvest

technology develops.

Nutritional Value

0022 The consumption of tropical fruit, like temperate

fruit, acts to supplement the diet (Table 4). Although

tropical fruit are generally a poor source of proteins

and lipids, they provide notable amounts of amino

acids (tryptophan, methionine, lysine), ascorbic acid

(and other organic acids such as malic and tartaric

acid), carotenes, vitamin E, carbohydrates, and fiber

(hemicelluloses, cellulose and pectic substances, as

well as more complex polymers such as lignin). Low

concentrations (per 100 g) of various mineral elem-

ents, such as calcium (8–125 mg), iron (0.4–1.6 mg),

potassium (84–170 mg), sodium (3–28 mg), and

phosphorus (24–64 mg), have been reported. (Refer

to individual nutrients.)

0023Tropical fruit with a high starch content, such as

plantains and breadfruit, comprise an entirely differ-

ent dietary niche. These fruit contribute a significant

portion of the daily carbohydrate intake. They are

widely consumed and have a similar nutrient compos-

ition to potato. Compared to the European potato,

they actually have a higher carbohydrate content.

0024Nutritionally, tropical fruit consumption is of

greatest importance to populations of the tropical

regions. Not only is daily intake of these fruit and

their products relatively high, but general dietary

habits and total food consumption may be quite

poor. This is particularly relevant in the less affluent

societies. In Uganda, for example, the laborers’ basic

rations are based on bananas. In the subtropical and

temperate regions, consumption is generally limited

to particular social groups. An interesting study of

local fruit consumption in Beijing identified the infant

component of the population as a significant con-

sumer group (based on daily intake).

Factors Affecting Nutritional Value

0025The nutritional value of tropical fruit is highly vari-

able. During fruit ripening, storage and subsequent

preparation, the nutritional characteristics of the

product may be dramatically altered. Other factors,

such as the cultivar type, growing region and maturity

at harvest, will have a further impact.

Fruit Maturity and Ripeness

0026The nutritional characteristics of tropical fruit

depend on their physiological maturity. During mat-

uration and ripening, fruit undergo numerous bio-

chemical changes, which may affect nutritional

status (Table 5). Starch is hydrolyzed into sugars,

organic acids are produced, and ash, minerals, and

water content are all increased. Fruit maturity be-

comes an important consideration as many tropical

fruit are traditionally consumed at an immature state.

Even when fruit are consumed ripe, considerable

variability may still exist. The sugar content of pine-

apples, for instance, increases from 4 to 15% during

the last 2 weeks of the ripening process. (See Ripening

of Fruit.)

FRUITS OF TROPICAL CLIMATES/Commercial and Dietary Importance 2783

tbl0004 Table 4 Composition of selected tropical fruit (per 100 g of edible portion)

Botanicalname Common name Food

energy

(kcal)

Moisture

(%)

Protein

(g)

Fat

(g)

To t a l

carbohydrate

(g)

Fiber

(g)

Ash

(g)

Calcium

(mg)

Phosphorus

(mg)

Iron

(mg)

Vitamin A

(mg)

Thiamin

(mg)

Riboflavin

(mg)

Nicotinic

acid

(mg)

Ascorbic

acid

(mg)

Achras zapota Sapodilla, chico 94 75.0 0.5 1.1 23.0 1.6 0.4 24 10 1.0 10 0.01 0.01 0.2 15

Ananas comosus Pineapple 52 85.4 0.4 0.2 13.7 0.4 0.3 18 8 0.5 15 0.08 0.04 0.2 61

Annona cherimola Cherimoya 82 76.6 1.1 0.2 21.3 1.9 0.8 34 35 0.6 0 0.09 0.13 0.9 17

A. muricata Soursop,

guanabana

60 83.1 1.0 0.4 14.9 1.1 0.6 24 28 0.5 5 0.07 0.05 0.9 26

Artocarpus communis Breadfruit 81 77.3 1.3 0.5 20.1 1.8 0.8 27 33 1.9 Trace 0.10 0.06 0.7 29

A. heterophyllus Jakfruit 98 72.0 1.3 0.3 25.4 1.0 1.0 22 38 0.03 0.06 0.4 8

Averrhoa carambola Carambola 36 90.0 0.5 0.3 8.8 0.6 0.4 5 18 0.4 90 0.04 0.02 0.3 35

Calocarpus mammosum Mamey sapote 121 65.6 1.7 0.4 31.1 2.0 1.2 40 28 1.0 115 0.01 0.02 2.0 22

Carica papaya Papaya (ripe) 32 90.7 0.5 0.1 8.3 0.6 0.4 20 13 0.4 110 0.03 0.04 0.3 46

Casimiroa edulis White sapote 65 82.0 1.4 0.4 15.7 1.7 0.5 8 18 0.2 15 0.04 0.07 0.5 23

Chrysophyllum cainito Star-apple,

caimito (ripe)

68 82.8 0.8 1.6 14.5 1.0 0.3 21 17 0.8 5 0.04 0.03 1.0 11

Citrus grandis Pummelo 34 90.3 0.6 0.2 8.5 0.8 0.4 26 26 0.5 0 0.04 0.02 0.02 35

Diospyros digyna Black sapote 66 82.0 0.7 1.2 15.0 1.6 1.1 18 26 1.2 40 0.02 0.03 0.2 29

Durio zibethinus Durian, civet 67 81.1 2.2 0.8 14.8 1.6 1.1 8 38 0.7 10 0.35 0.20 0.7 24

Eugenia dombeyi Grumichama 53 85.3 0.6 0.3 13.4 0.6 0.4 40 14 0.5 20 0.04 0.03 0.3 19

Garcinia mangostana Mangosteen 60 84.9 0.5 0.1 14.3 10 20

Litchi chinensis Lychee 60 83.1 0.8 1.0 15.7 0.1 0.3 5 31 1.1 0 0.02 0.03 0.9 72

Lucuma caimito Abiu 140 60.6 1.4 0.4 36.3 0.9 0.9 22 41 1.0 130 0.02 0.02 3.4 49

Mangifera indica Mango (ripe) 59 83.5 0.5 0.2 15.4 0.8 0.4 12 12 0.8 630 0.05 0.06 0.4 53

Musa paradisiaca Plantain (mature) 122 65.6 1.0 0.3 32.3 0.5 0.8 8 34 0.8 175 0.06 0.04 0.06 20

M. sapientum Common banana

(mature)

110 68.8 1.2 0.2 29.0 0.4 0.8 7 28 0.5 65 0.04 0.04 0.7 15

Myrciaria cauliflora Jaboticaba 46 87.1 0.1 0.0 12.6 0.1 0.2 6 9 0.5 0 0.02 0.02 0.2 23

Passiflora ligularis Sweet granadilla 94 76.3 2.4 2.8 17.3 4.2 1.2 10 64 0.9 5 0.00 0.11 1.6 20

Rheedia madruno Madrono 46 87.2 0.6 0.1 11.9 1.0 0.2 12 22 0.4 0 0.06 0.04 0.3 6

Sandoricum koetjape Santol 46 87.0 0.8 0.1 11.8 0.1 0.3 4 17 0.4 0 0.05 0.03 0.7 86

Syzygium malaccense Malay apple 32 90.9 0.6 0.1 8.0 0.7 0.4 6 16 0.4 Trace 0.03 0.03 0.3 13

From Wilson D and Wilson I (1988) Tropical fruit food composition table. Rare Fruit Council of Australia Newsletter 51: 5–9.

Preparation

0027 Although the majority of tropical fruit are consumed

fresh, there are many cases where consumption is

only after some form of preparation. Cooking of the

whole fruit, or a paste, is very common for many

tropical fruit. This process may be necessary, as

some fruit are purgative if eaten raw. The nutritional

status of the fruit is dramatically affected as a result.

Fresh green plantains, for example, have an energy

count of 378–613 J (90–146 cal) per 100 g of edible

portion, compared to 1508 J (359 cal) as a dried

product and 323 J (77 cal) after cooking.

Cultivar Type and Growing Region

0028 Many cultivar types have distinct nutritional charac-

teristics. Although commonly equated to flavor, color,

and taste, differences in ascorbic acid, protein, amino

acid, and carotene levels are regularly reported. The

growing region is also known to have an effect. Cher-

imoyas produced in Ecuador have 17 mg of ascorbic

acid (per 100 g), whereas a similar cultivar grown in

nearby Colombia has just 5 mg of ascorbic acid.

See also: Bananas and Plantains; Carcinogens:

Carcinogenic Substances in Food: Mechanisms; Citrus

Fruits: Types on the Market; Mangoes; Papayas;

Pineapples; Ripening of Fruit; Spoilage: Bacterial

Spoilage; Storage Stability: Mechanisms of Degradation

Further Reading

Almeyda N and Martin FW (1977) Cultivation of Neg-

lected Tropical Fruits with Promise. Washington, DC:

United States Department of Agriculture, Agricultural

Research Service.

Anonymous (1989) Fruit and Tropical Product. London:

Commonwealth Secretariat Publications.

Collins JL (1960) The Pineapple. New York: Interscience.

Hulme AC (1971) The Biochemistry of Fruits and their

Products. London: Academic Press.

Kitagawa H, Matsui T, Kawada K and Agravante JU (1990)

Japan as a market of tropical fruit. Acta Horticulturae

269: 41–45.

Lindsay P and Cull B (1982) Fruit Growing in Warm

Climates. New South Wales: Reed Books.

Loesecke HW (1960) Effect of harvesting and handling

practices on composition of unprocessed food. In: Harris

RS and Loesecke HW (eds) Nutritional Evaluation of

Food Processing, pp. 58–91. New York: John Wiley.

Menzel CM, Watson BJ and Simpson DR (1988) The lychee

in Australia. Queensland Agricultural Journal 114:

19–27.

Miller CD, Bazore K and Bartow M (1957) Fruits of

Hawaii. Honolulu: University of Hawaii Press.

Mukherjee SK (1971) Origin of mango (Mangifera indica).

Economic Botany 26: 260.

Oliviera JFS (1974) The nutritional value of some foods

consumed on San Tome Island. Ecology of Food and

Nutrition 3: 237.

Page P (1984) Tropical Tree Fruits for Australia, Informa-

tion Series Q 183018. Brisbane: Queensland Depart-

ment of Primary Industries.

Purseglove JW (1974) Tropical Crops: Dicotyledons.

London: Longman.

Samson JA (1980) Tropical Fruits. New York: Longman.

Wills RBH, Lee TH, Graham D, McGlasson WB and Hall

EG (1982) Postharvest: An Introduction to the Physi-

ology and Handling of Fruits and Vegetables. Sydney:

New South Wales University Press.

Wilson D and Wilson I (1988) Tropical fruit food compos-

ition table. Rare Fruit Council of Australia Newsletter

51: 5–9.

tbl0005 Table 5 Changes in the nutritional status of banana during ripening (expressed as a percentage of fresh weight)

Constituents Days after harvest

0357911

Water 74.4 75.6 75.4 75.9 76.4 77.4

Protein (N 6.25) 0.86 0.89 0.88 0.81 0.86 0.86

Crude fat 0.10 0.23 0.31 0.47 0.35 0.17

Reducing sugars (as invert) 0.24 2.81 7.24 10.73 12.98 15.31

Nonreducing sugars (as sucrose) 0.62 4.85 6.52 6.12 3.89 2.60

Total sugars 0.86 7.66 13.76 16.85 16.87 17.91

Starch 20.65 12.85 6.00 2.93 1.73 1.21

Protopectin (as calcium pectate) 0.53 0.56 0.31 0.34 0.21 0.22

Pectin (as calcium pectate) 0.27 0.36 0.34 0.37 0.40

Ash 0.74 0.79 0.79 0.76 0.72 0.74

Total acid (as citric) 0.18 0.25 0.32 0.29 0.26 0.23

From Loesecke HW (1960) Effect of harvesting and handling practices on composition of unprocessed food. In: Harris RS and Loesecke HW (eds)

Nutritional Evaluation of Food Processing, pp. 58–91. New York: John Wiley.

FRUITS OF TROPICAL CLIMATES/Commercial and Dietary Importance 2785

Fruits of the Sapindaceae

C M Menzel, Maroochy Research Station, Nambour,

Queensland, Australia

Introduction

0001 The Sapindaceae (or soapberry) family contains more

than 1000 species from 125 genera, mostly trees and

shrubs, but rarely herbs, and with a wide distribution

in the tropics and warm subtropics. The majority of

species are native to Asia, although there are a few in

South America, Africa and Australia.

0002 Many species are important timber trees or are

used as soap substitutes, sources of drugs, beverages,

or nuts. However, it is the attractive, eye-catching

fruit of the subfamily Nepheleae that are of greater

economic interest, especially those that are popular

throughout the Orient: lychee or litchi (Litchi

chinensis), longan (Dinnocarpus longan), rambutan

(Nephelium lappaceum) and pulasan (Nephelium

mutabile). Lychee is more widely grown than the

other species, and is the most important member of

the Nepheleae. The four species are similar in

growth and fruiting habit, but differ in fruit morph-

ology and climatic adaptation. Lychee is regarded as

one of the kings of fruits and has a very long history in

China. The fruit are very attractive with a bright red

skin covered by angular or conical protuberances.

Longan fruit resemble lychee fruit but are smaller,

smoother and yellow–tan to brown in color. The

fruit are also milder in flavor and less acidic. About

a third of people in China and Thailand rate the taste

of longan equal to that of lychee or better. Canned

longans are also more acceptable than canned lychee.

Rambutan and pulasan fruit are similar to lychee,

usually with red skin. However, long hairs or spin-

terns replace the protuberances. Rambutan and pula-

san are strictly tropical, cropping only in warm,

wet lowland tropical areas. In contrast, lychee and

longan bear well in the warm subtropics or at eleva-

tion in the tropics.

Origin, Distribution and Commercial

Importance

0003 The lychee originated in southern China and possibly

in northern Vietnam and the Malay Peninsula, and

wild lychee trees can still be found growing in

several rainforest areas in these locations. The wild

lychee is similar morphologically to cultivated lychee

in China, in particular the Jin Feng types. The fruit

are edible, but the aril or flesh is relatively thin and

sour.

0004The Litchi genus contains two other subspecies

that have not been commercialized, L. chinensis ssp.

philippinensis (kumingi), which developed in the

Philippines and Papua New Guinea at high elevation

(Luzon, Sibuyan, Samar, and Mindanao), and L. chi-

nensis ssp. javensis, which has been recorded in the

Malay Peninsula and Indonesia. Philippines lychee

has long oval-shaped fruit with long thorn-like protu-

berances. Fruit split in the middle when ripe, and

the aril only partly covers the seed and is not edible.

L. chinensis ssp. javensis is a rare specimen in Chinese

gardens in West Java and Indo-China, and has

fruit similar to the cultivated lychee, but the aril is

thinner. It is reported to flower and fruit well

under wet tropical conditions. Many of the Malayan

specimens of Litchi belong to ssp. chinensis not ssp.

javensis.

0005The longan (D. longana ssp. longan var. langon)

originated either in subtropical China and Vietnam or

in the area between Myanmar and India, and wild

trees have been found growing amongst the rainfor-

ests on Hainan Island, near northern Vietnam. There

are six species in the genus Dianocarpus, all from

tropical and subtropical Asia, and Australia but

longan is the only one grown for its edible fruit. D.

longan spp. malesianus (mata kuching) produces fruit

of a similar size to longan. Fruit have a tough skin

that is pale dull yellow with dark raised specks. The

aril, which envelops a big seed, is whitish, translucent

and sweet and in good forms nearly 0.5 cm thick,

although it is usually much thinner. Trees grow wild

in Malaysia, Borneo, Sumatra, and the Celebes.

0006Rambutan and pulasan are thought to be native to

west Malaysia and Sumatra, although trees that have

escaped from cultivation blur the original distribu-

tion. They are close relatives of the lychee, and are

equally desirable fruit, but are not as well known. The

fruit are very similar to each other and may some-

times be confused. Trees are smaller in pulasan, leaf-

lets narrower, and branches more open, and there are

fewer fruit in a cluster. The fruit skin is thicker, and

the spinterns or tubercles very much shorter. Trees are

also reported to be less productive. Other species of

Nephelium with edible arils that are occasionally

consumed include N. eriopetalum (lotong), N. glab-

rum (redan), N. philippense (bulala), and N. excro-

spermoides (aluao).

0007The lychee was introduced in the tropical and sub-

tropical world from China from the end of the seven-

teenth century and is now grown within 15–35



latitude in most countries. The distribution of lychee

to the rest of the world has been slow, possibly be-

cause of the need for propagation by air-layering and

the narrow ecological range of most cultivars. The

most important production areas today are China

2786 FRUITS OF TROPICAL CLIMATES/Fruits of the Sapindaceae

(1 300 000 t), Vietnam (50 000 t), India (430 000 t),

Pakistan, Thailand (80 000 t), Indonesia, Madagascar

(35 000 t), South Africa (9500 t), Mexico, and Aus-

tralia (5000 t). In China, lychee is mainly grown in

three southern provinces: Guangdong, Guangxi, and

Fujian.

0008 The longan reached Thailand in the late nineteenth

century and Hong Kong, Hawaii, Florida, and Aus-

tralia by the early to mid-twentieth century. However,

despite its wide environmental adaptation, longan is

commercialized only in China (500 000), Thailand

(240 000 t), and Vietnam (365 000 t). Longans are

rated 12th in order of total production for tropical

fruits in Thailand, with an average of 4–6 times more

longans produced than lychees.

0009 Rambutan and pulasan are widely distributed

in the humid tropics of South-east Asia. The largest

commercial plantings of rambutan occur in

Malaysia (80 000 t), Indonesia (148 000 t), Thailand

(430 000 t), and the Philippines (20 000 t). In Malay-

sia, rambutan is the most important fruit crop,

whereas in Thailand and Java, rambutan ranks third

after mango and tangerine. In the Philippines, rambu-

tan was introduced from Indonesia only in this cen-

tury and is not listed in the 20 main tree fruits. The

pulasan is widely grown in the western part of Java,

with smaller plantings in other parts of Indonesia,

Malaysia, and Thailand.

0010 Lychees and longans are well known and popular

fruit in most Asian countries, and significant quan-

tities are traded each season. The Hong Kong and

Singapore markets are well serviced and highly com-

petitive, and have very high standards for imported

produce. Consumers know and prefer large highly

colored sweet fruit with small seeds and firm flesh.

0011 Hong Kong and Singapore are the main markets

for lychees in South-east Asia, with the fruit coming

from China, Taiwan, Vietnam, and Thailand. Most

of the fruit enter between June and July. The total

market is about 20 000 t. Prices range from A$1 to

A$11 per kilogram, depending on the fruit quality

and supply. In 1994, Thailand exported 6828 t, but

mostly as canned fruit (5834 t).

0012 Thailand exports up to 50% of its longan crop in

some seasons, and longans are the most important

export fruit crop. In 1994, for instance, it exported

46 123 t to Hong Kong, China, Singapore, Malaysia,

Indonesia, and the USA, mostly as fresh fruit

(32 628 t), but also dried (3335 t), frozen (140 t), and

canned (10 020 t). Prices for fresh fruit in Asian

markets fluctuate considerably during the season.

Early fruit may fetch A$3–5 per kilogram, but as

supplies increase, the price drops to A$0.40–1.00 per

kilogram. Average prices during the season are about

A$1.50 per kilogram. Singapore consumers pay more

for Thai fruit because they are normally larger and

sweeter than those from China and Taiwan. Retail

prices for longan are about half those for lychees.

0013Lychees share in the growth of exotics in western

Europe. Exotics are seen as a bright spot in fruit

wholesaling, with increased turnover and higher

prices compared with temperate fruits. The UK,

France, and Germany import about 15–20 000 t of

lychee, mainly from Madagascar and South Africa,

with smaller quantities from Reunion, Mauritius, and

Israel. Fruit are normally available from November

to early March, with peak supplies during mid-

December to late January. Prices range from A$4 to

A$10 per kilogram.

0014Exports of rambutan are considerably reduced

compared with lychee and longan. Most of the pro-

duction is sold in the domestic markets. Thailand

and Malaysia export about 5000 t, mainly to Singa-

pore and Hong Kong. The export of rambutans does

not play a major role in terms of foreign exchange

earnings.

Description of Fruit

0015Lychee fruit are small (3.0–5.0 cm diameter) and vari-

able in shape from round to egg- or heart-shaped. The

skin color is bright red, dull red, purple–red or pink-

ish red, depending on cultivar. Some cultivars also

have distinctive yellow blotches on the skin. The

skin has protuberances on each segment that can be

smooth, sharp-pointed, or hair-like and sharp.

0016The fleshy edible portion of the fruit is called an aril

and is an outgrowth of the seed stalk. It grows as the

fruit develops until it completely covers the seed,

although in a few cultivars, the aril may not com-

pletely envelope the seed, especially during periods

of drought. Such cultivars have a low flesh recovery

and are poor marketing types, especially in Asian

markets. The aril is white and translucent and has

the consistency and flavor of a prime muscat grape.

Cultivars vary greatly with respect to texture, aroma,

and flavor of the aril.

0017Each fruit normally contains one chestnut brown

to dark brown, ovoid to oblong seed about

1.0–3.3 cm long and 0.6–1.2 cm wide. In some culti-

vars, a high proportion of seeds may be abortive. The

abortive seeds are small and shrivelled and are known

as ‘chicken tongue’ seeds. Fruit with abortive seeds

are preferred, and often attract a higher price, for

although they are somewhat smaller than fruit with

normal seeds, they usually contain a higher propor-

tion of flesh. The proportion of small or shrivelled

seeds is an important characteristic of a cultivar, and

varies from season to season and orchard to orchard.

Fruit with chicken tongue seed are more susceptible

FRUITS OF TROPICAL CLIMATES/Fruits of the Sapindaceae 2787