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

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abnormal nodules. Alcoholic cirrhosis is mostly

micronodular in type, with a size of nodules from

1 to 5 mm. Macronodules with a size ranging from

5 to 50 mm may occur, especially in the late phases of

the disease. The loss of normal liver architecture, with

separation of the portal tracts and the central zones of

the liver by septa of fibrotic tissue, results in alter-

ations of the vascular supply and a disturbance of the

intrahepatic blood circulation.

0016 Morbidity and mortality resulting from alcoholic

cirrhosis are related principally to the loss of liver cell

function, to derangements in the vascular system of

the liver, or to both. The onset of cirrhosis is often

insidious and associated with nonspecific symptoms

such as fatigue, anorexia, weight loss, nausea, and

abdominal discomfort. As the disease progresses,

signs of hepatocellular failure became prominent.

The most severe complications are iron overload,

hepatic encephalopathy, and portal hypertension

with ascites and bleeding from esophageal varices.

0017 In association with cirrhosis of the liver, hepatocel-

lular carcinoma may develop. The pathogenesis of the

carcinomatous transformation is still unclear, espe-

cially because these tumor forms may also occur in

noncirrhotic livers.

0018 Ethanol leads to a number of metabolic and struc-

tural alterations in the liver that predispose this organ

to derangements in its functional integrity. These are

as follows: an increase in the ratio of NADH (the

reduced form of nicotinamide adenine dinucleotide,

or NAD) to NAD; interactions of ethanol with lipid

and protein metabolism; stimulation of fibrosis with

deposition of collagen; inhibition of liver cell regener-

ation; humoral and cellular immunological alter-

ations; and excessive production of free radicals and

cytokines. Alcohol induces cell death and inflamma-

tion, which can result in scarring that distorts the

liver’s internal structure and impairs its function.

Acetaldehyde, the first oxidation product of ethanol

metabolism, may exert some toxic effects of its own

in liver tissue; it activates stellate cells directly and

promotes liver scarring in the absence of inflamma-

tion.

0019 All stages of liver injury can be produced in the

baboon fed high-protein and vitamin-supplemented

diets. This evidence suggests that toxic effects of

alcohol, and not malnutrition, are the principal

causes for the development of cirrhosis in chronic

alcoholics. But alcohol abuse establishes only the

conditions for the generation of cirrhotic lesions,

which require the addition of some independent

factors emerging over time.

0020 Abstinence from alcohol is the essential factor for

prevention and treatment of alcoholic cirrhosis. If

irreversible liver damage is already established, some

complications of cirrhosis can be alleviated by nutri-

tional treatment. Portal-systemic encephalopathy, for

example, often responds to an application of amino

acid mixtures, enriched with branched-chain amino

acids, whereas ascites responds favorably to sodium

restriction.

Wernicke’s Encephalopathy and

Korsakoff’s Syndrome

0021Wernicke’s encephalopathy and Korsakoff’s psych-

osis are diseases of the central nervous system (CNS)

secondary to alcoholism. They represent a continuum

of the same neuropathological process and develop in

about 2–3% of alcoholics. Wernicke’s disease is often

followed by Korsakoff’s syndrome. Severe alcoholics

may have both diseases, but some of them show

Korsakoff’s psychosis without preceding Wernicke’s

encephalopathy. Wernicke’s disease is an acute or

chronic encephalopathy with a triad of clinical abnor-

malities: ophthalmoplegia, ataxia, and mental con-

fusion. Korsakoff’s syndrome is a psychosis with

marked abnormalities in cognitive function: the car-

dinal symptoms are anterograde amnesia, disorien-

tation, learning deficits, and confabulations. The

relationship between the two diseases is not entirely

clear. The neuropathological changes seen in autopsy

materials of Wernicke–Korsakoff patients consist of

circumscribed, symmetrical lesions in the diencepha-

lon and brainstem. Most affected are the mammillary

bodies and the dorsomedial nuclei of the thalamus. In

acute cases the lesions are widespread and severe. In

chronic cases the lesions are more restricted and show

great variations in extent and severity within the

affected area. There are corresponding variations of

the clinical symptoms.

0022Extreme deficiency of thiamin, induced by malnu-

trition and interaction of ethanol with thiamin ab-

sorption and metabolism, is regarded as the primary

cause of this syndrome. Patients with Wernicke’s dis-

ease often have a high energy intake, consisting

mainly of ethanol and/or carbohydrates, without suf-

ficient protein and vitamins. Beyond that a direct

toxic effect of alcohol on the brain has also been

implicated. The Wernicke–Korsakoff’s disease is not

confined to alcoholism, but is also present in other

conditions associated with thiamin malnutrition, e.g.,

hyperemesis gravidarum, Hodgkin’s lymphoma, car-

cinoma of the stomach, and anorexia nervosa. Thia-

min application can reverse Wernicke’s syndrome in

many but not all patients, at least when administered

early in the course of the disease. In contrast, Korsak-

off’s patients often show poor response to thiamin

therapy. Additional factors, of as yet unknown origin,

seem to be necessary for the full development of

1326 CIRRHOSIS AND DISORDERS OF HIGH ALCOHOL CONSUMPTION

Korsakoff’s psychosis. There is evidence to suggest

that a genetic predisposition is involved in the eti-

ology of the Wernicke–Korsakoff syndrome.

0023 In some patients a variant form of transketolase

with a low affinity for its coenzyme thiamin pyro-

phosphate has been diagnosed. This isoenzyme re-

quires much larger amounts of thiamin to function

than the normal enzyme. Some authors suggest that a

variant transketolase and thiamin deficiency together

contribute to the pathogenesis of the brain damage of

the Wernicke–Korsakoff syndrome. In other studies

this hypothesis has not been confirmed. (See Anorexia

Nervosa.)

Alcoholic Polyneuropathy, and Beriberi in

Alcoholics

0024 Symmetric and predominantly distal polyneuropathy

is probably the most common sequela of chronic

alcohol abuse. It occurs in about 20% of all alcohol-

ics. First symptoms include paresthesia, dysesthesia

and pain sensations affecting primarily the lower ex-

tremities, accompanied by reduced or absent reflex

activity. These symptoms are usually followed in the

more advanced stages of the disease by marked motor

impairments, such as weakness and atrophy of the

anterior tibial muscles. Electrophysiological slow-

down of the sensory and motor conduction velocities

of the peripheral nerves, as well as myopathic changes,

are usually observed. The predominant pathological

abnormalities are distal pronounced axonal degen-

erations, mainly of the large fibers with a gradient

of changes toward the extremities (‘dying-back de-

generation’). Segmental demyelination appears as a

secondary phenomenon. Alcoholic polyneuropathy

is clinically indistinguishable from beriberi (‘dry

beriberi’) neuropathy. As in the Wernicke–Korsakoff

syndrome, thiamin deficiency is regarded as the pri-

mary cause. Besides that, a long-lasting low protein-

energy supply seems to be one of the main pathogenic

factors for the development of the typical lesions of

peripheric nerves. In addition, insufficient intake

or absorption of pyridoxine, folates, B

and other

B vitamins contributes to the development of the

disease, and direct toxic effects of ethanol and its

metabolites are involved in the destruction of nerve

ultrastructure and function. Recovery from alcoholic

peripheral neuropathy is slow and often incom-

plete. The most important therapeutic factors are

abstinence from alcohol and improvement of the

overall nutritional status. Additional supplementa-

tion with high doses of B-complex vitamins is ne-

cessary. With this therapeutic schedule a slow

diminution of symptoms may be expected in many

but not all cases.

Pancreatitis

0025The association between alcohol consumption and

pancreatitis is well recognized. In general, about

60–90% of all cases of chronic pancreatitis are alco-

hol-related. As with alcoholic cirrhosis, there has

been an increasing prevalence of alcoholic pancrea-

titis in industrialized countries in the last 30 years.

This disease often develops without obvious clinical

symptoms. However, in autopsies of patients with a

history of alcoholism, marked pancreatic lesions are

frequently observed. Patients with severe or compli-

cated forms of this disease may rapidly develop

marked generalized malnutrition. (See Gallbladder.)

0026A favored hypothesis regarding the mechanism of

action of chronic alcohol consumption on the pan-

creas is the observation that ethanol increases the

protein content of pancreatic juice, with a concomi-

tant decrease in water and electrolytes. This induces

a precipitation of protein plugs within the pancre-

atic ducts, followed by retraction and calcification,

resulting in pancreatic stones, atrophy of the duct

epithelium, and proliferation of the connective tissue.

The consequences are stenosis or dilatations of the

ducts, cysts and pseudocysts, and progressive dis-

appearance of the pancreatic exocrine tissue which

is replaced by fibrosis. Pathologically, the gland is

edematous and hemorrhagic. Besides chronic over-

consumption of alcohol, both a high-fat, high-protein

diet and, paradoxically, malnutrition have been im-

plicated in the pathogenesis of the disorder.

0027Alcoholic pancreatitis tends to be recurrent and

progressive and to result in pancreatic exocrine insuf-

ficiency. Some 1–2% of alcoholics suffer from an

acute form. This complication can be quite severe,

with violent epigastric pain, nausea, and vomiting.

Cases of sudden death from acute attacks have been

reported.

0028Even heavy drinking does not modify the risk for

pancreatic cancer. Several epidemiologic studies do

not support an association between alcohol consump-

tion and incidence of pancreatic cancer.

Effect of Chronic Alcohol Consumption on

the Brain

0029Ethanol – in common with other centrally acting

agents – rapidly diffuses across the blood–brain bar-

rier and equilibrates in brain tissue. Its concentration

depends upon the plasma concentration, vasculariza-

tion, local blood flow, and water content of the con-

cerned brain area. Chronic ethanol consumption is

associated with a variety of deficits in brain function

over a wide range of doses and is often followed by

clinically obvious brain damage.

CIRRHOSIS AND DISORDERS OF HIGH ALCOHOL CONSUMPTION 1327

Alcoholic Dementia

0030 Alcoholics often suffer from disorders in cognitive

processes, varying from a relatively slight memory

reduction to deep dementia. The deficits in cognitive

function are similar to those seen in patients with

Alzheimer’s disease or multiinfarct dementia. His-

topathologically, the brain structures that are pos-

sibly involved do not show any lesion or atrophy,

but there is considerable evidence that alcoholic de-

mentia may potentially result from progressive loss of

some neurons, synapses, and/or their associated re-

ceptors. Prolonged abstinence has a considerable re-

ducing effect on dementia symptoms, but in most

subjects the reversibility is only partial. Alcoholic

dementia seems to be a severe form of Korsakoff’s

syndrome.

Alcohol Tolerance and Dependence

0031 Functional tolerance and physical dependence are

inexorably linked phenomena reflecting adaptive

changes in the brain which compensate for the inhib-

ition of functions by ethanol. Functional tolerance

means a decrease in the sensitivity of the CNS pro-

duced by chronic alcohol intake. Physical dependence

means hyperexcitability of the CNS following alcohol

withdrawal after adaptation. The molecular mechan-

isms underlying both phenomena are as yet unknown.

Possibly the effects are primarily related to changes in

the microorganization and physical state of brain

membranes.

Brain Shrinkage

0032 Cerebral shrinkage seems to be one of the most fre-

quent brain lesions induced by chronic alcohol con-

sumption. It can be demonstrated by computerized

tomography (CT) scanning in patients with alcohol-

ism and even in ‘social drinkers.’ Cerebral shrinkage

relates to a loss of white matter rather than of gray

matter. In alcoholics the shrinking results in a lower

brain weight compared to age- and sex-matched con-

trols. After cessation of alcohol drinking cerebral

shrinkage is often partially reversed.

Cerebellar Atrophy

0033 Many alcoholics show cerebellar atrophy with pro-

gressive ataxia of stance and gait and, occasionally,

an impairment of speech and ocular motility. This

cerebellar degeneration is characterized by great

uniformity of the clinical and pathological manifest-

ations. In the majority of cases the disorder develops

over several weeks or months, followed by years of

stability. The pathological changes consist of degener-

ation of neuronal elements of the cerebellar cortex,

particularly of the Purkinje cells. The dendritic

networks of these cells show alterations in length

parameters under the influence of ethanol in rats.

Topographically, the lesions of the cerebellum are

restricted to the anterior and superior vermis and to

the hemispheres.

0034Although cerebellar atrophy is most frequently en-

countered in chronic alcoholic patients, it has also

been reported in old people and in malnourished

individuals, who allegedly did not drink. It has been

postulated that alcohol and the aging process super-

imposed upon malnutrition may be responsible for

the damage caused to the cerebellum.

Fetal Alcohol Syndrome

0035Prenatal exposure to alcohol produces various mor-

phological, physiological, and behavioral abnormal-

ities in the newborn, termed fetal alcohol syndrome

(FAS). It has been observed in 1 in every 1000 chil-

dren born to alcoholic mothers, and is the most

common known cause of mental retardation. The

Fetal Alcohol Study Group of the Research Society

on Alcoholism has defined three criteria for the diag-

nosis of FAS:

0036growth retardation

0037abnormalities of the CNS

0038abnormal facial features

0039The mechanisms by which alcohol produces these

effects are not yet fully elucidated. Possibly ethanol

affects NMDA and g-aminobutyric acid receptors in

the developing brain, leading to neuron death. The

minimum level of alcohol consumed during preg-

nancy that causes FAS has not been established.

Animal models have demonstrated conclusively that

ethanol can cross the placenta and is teratogenic in

several species. The effect is dose-dependent and the

type of malformation observed depends upon the

stage of development when the exposure occurred.

Besides the toxic effects of ethanol, another potential

cause of FAS is maternal and/or fetal malnutrition

induced by impaired placental transfer of essential

nutrients.

0040Among the neuroanatomical alterations observed

in humans and animal models with FAS are decreased

brain weight, delays in dendritic development, de-

creased numbers of pyramidal neurons in the hippo-

campus, and sprouting in the dentate gyrus. The

clinical symptoms of the CNS dysfunction are

mental retardation, hyperactivity, and learning dis-

abilities. Despite nutritional rehabilitation, the phys-

ical and mental development of the children remains

impaired. To date, a safe intake of alcohol for preg-

nant women has not been established. (See Preg-

nancy: Safe Diet.)

1328 CIRRHOSIS AND DISORDERS OF HIGH ALCOHOL CONSUMPTION

See also: Alcohol: Metabolism, Beneficial Effects, and

Toxicology; Alcohol Consumption; Anorexia Nervosa;

Calcium: Physiology; Cholecalciferol: Physiology;

Cobalamins: Physiology; Folic Acid: Physiology;

Gallbladder; Liver: Nutritional Management of Liver and

Biliary Disorders; Magnesium; Pregnancy: Safe Diet;

Retinol: Physiology; Thiamin: Physiology; Vitamin B

Properties and Determination; Zinc: Physiology

Further Reading

Bitsch I (1983) Perspektiven der Alkoholforschung. Erna¨h-

rungs-Umschau 30: 132–135.

Bitsch R (1987) Alkohol und Vitaminstoffwechsel. Erna¨h-

rungs-Umschau 34: 161–166.

Eriksson K, Sinclair JD and Kiianmaa K (eds) (1980)

Animal Models in Alcohol Research. London.

Hall PM (ed) (1995) Alcoholic Liver Disease: Pathology

and Pathogenesis, 2nd edn. London.

Kalant H, Khanna JM and Israel Y (1991) Advances in

Biomedical Alcohol Research. Oxford.

Lindros KO, Ylikahri R and Kiianmaa K (1987) Advances

in Biomedical Alcohol Research. Oxford.

National Institute on Alcohol Abuse and Alcoholism (1999)

Rockville, Alcohol Alert No 42, 46.

Shils ME, Olson JA and Shike M (eds) (1999) Modern

Nutrition in Health and Disease, 9th edn. Baltimore:

Lippincott, Williams & Wilkins.

Torvik A (1987) Brain lesions in alcoholics: neuropatholo-

gical observations. Acta Medica Scandinavica Supple-

mentum 717: 47–54.

Victor M, Adams RD and Collins GH (1989) The Wer-

nicke–Korsakoff Syndrome, 2nd edn. Philadelphia.

Ziegler EM and Filer LJ (eds) (1996) Present Knowledge in

Nutrition, 7th edn. Washington, DC: ILSI.

Citric Acid Cycle See Tricarboxylic Acid Cycle; Oxidative Phosphorylation

CITRUS FRUITS

Contents

Types on the Market

Composition and Characterization

Oranges

Processed and Derived Products of Oranges

Lemons

Grapefruits

Limes

Mandarins

Types on the Market

J Forsyth, Formerly of New South Wales Agriculture,

Orange, NSW, Australia

J Damiani, Australian Citrus Growers Inc., Mildura,

Victoria, Australia

Background

0001 Citrus is the main fruit tree crop grown throughout

the world. It is made up of many species that vary in

importance due to different uses, markets, growing

conditions, and climatic zones. The large production

has significance in local and world trade for both

fresh and processed products. Brief details on the

classification of the species, growing regions and con-

ditions, production statistics, with the utilization of

the main and also lesser known types are discussed.

Classification

0002The taxonomic classification of the Citrus species is

complex and diverse, and not universally agreed

upon, but those used by Swingle and Reece will be

followed in this article. Citrus, as a social and cultural

CITRUS FRUITS/Types on the Market 1329

fruit crop, also has countless local names and iden-

tities throughout the world, often for an identical

cultivar.

0003 Citrus trees belong to the plant family Rutaceae,

subfamily Aurantioideae, which comprises 33 well-

known and described genera and 203 species. In add-

ition, many natural and man-made hybrids also exist

that have resulted in new edible cultivars. Many

genera contain unusual or remote relatives of citrus

with nonedible fruit, but of ornamental value like

Merrillia and Murraya, or have genetic importance

in breeding programs like Poncirus and Severinia.

0004 True citrus fruit trees, which have a berry fruit

called a hesperidium, belong to six genera: Citrus,

Fortunella, Poncirus, Microcitrus, Eremocitrus,and

Clymenia. Only the Citrus and Fortunella genera

have fresh fruit cultivars of commercial importance.

Both these genera are evergreen and unifoliate, and

the genus Citrus provides nearly all of the commercial

cultivars grown throughout the world.

Main Types on the Market

0005 Citrus fruits are principally marketed according to

how they are consumed:

0006 As fresh or dessert fruits – sweet oranges, manda-

rins (eaten out of hand), grapefruit, or pummelo

(spooned). Juice, slices, segments, rind, and leaves

are also used to garnish food.

0007 As processed products – juice (fresh, chilled,

frozen, canned, blended, or concentrated), syrups

and cordials, segments and rind oil, or essence.

After the juice is extracted, there remain residues

that can be a source material from which over 300

valuable byproducts can be produced. Some spe-

cialized types are also candied, dried, or used for

marmalade manufacture. (See Citrus Fruits: Com-

position and Characterization; Processed and De-

rived Products of Oranges.)

0008 The main types of fresh citrus fruits on the export

or main local markets, and also used for processing,

are normally broadly grouped as oranges, mandarins,

lemons and limes, and grapefruit. There is also a wide

range of other minor or lesser known species and

types that may have regional or local significance.

Some of these are mentioned in a later section. The

following brief comments are made on the main citrus

types, as listed in available statistics and found on

world markets.

Sweet Oranges

0009 The sweet orange types (Citrus sinensis [L.] Osbeck)

are the most widely grown citrus fruits throughout

the world and provide the greatest fruit marketing

production. The many known cultivars can be sub-

divided into three main groups as the acidless or sugar

oranges do not contribute to world trade:

0010Common oranges (also known as blond or white

oranges). The Valencia is the main cultivar grown,

with harvesting from spring to autumn, depending

on local climates. The fruit is dual purpose and

suitable for both eating as fresh fruit or processing,

while seedless types are also grown, e.g., Delta and

Midknight. Other common oranges are often seedy

and mainly suitable for processing, e.g., Pera,

Hamlin, and Pineapple.

0011Navel oranges are also widely grown as winter

seedless eating fruit (Figure 1). The Washington

navel with numerous clones or selections is the

most important cultivar, while there are many

others navels (over 50 distinct varieties or clones)

available that spread the maturity period from

early (like Fukumoto, Navelina, Leng, and New-

hall) to late (Lane and Navelate), and to what are

now being called ‘summer navels,’ following the

location of many new very late maturing cultivars

in Australia, e.g., Powell, Chislett, and Barnfield. A

new pink/red fleshed navel – Cara Cara – is also

creating marketing interest.

0012Blood or pigmented oranges have been popular in

Mediterranean countries for their distinctive flavor

and both rind, flesh, and juice pigments, e.g.,

Tarocco, Sanguinello, and Moro.

fig0001Figure 1 (see color plate 25) Navels are the most important

sweet, juicy, and seedless orange marketed for fresh fruit

consumption.

1330 CITRUS FRUITS/Types on the Market

Mandarins

0013 Mandarins are also referred to as ‘tangerines’ in some

countries. The mandarin group and related hybrids

is very diverse (with over 100 cultivars), but can

be classified into a number of main groups, some of

which contain a large number of subgroups. This fruit

is more seasonal, with each cultivar maturing and

suitable for harvesting only over a short period of

time, e.g., 6–8 weeks. Some are now available for

the main types that can supply fresh fruit from very

early to very late maturity. Mandarins production is

increasing with a consumer trend towards easier to

peel, segment, and seedless lunch/eaten out of hand

fruit, while limited quantities are processed into juice

or canned segments.

0014 Satsuma mandarins (C. unshiu Marcovitch) are

also known as ‘Unshiu mikan’ in Japan and

China. This is an important expanding seedless

group that includes Clausellina, Miho, Miyagawa

and Okitsu.

0015 Common mandarins (C. reticulata Blanco) are a

very extensive group of different cultivars widely

grown and available in world markets, e.g., Im-

perial, Nova, Ponkan, Sunburst, and Fortune.

The group also includes the seedless clementines

(like Marisol, Clemenules, and Hernandina), and

two hybrid groups, e.g., tangors, which are hybrids

of the mandarin and orange (like Murcott and

Ellendale), and tangelos, hybrids of the mandarin

and grapefruit or pummelo (Minneola and Sem-

inole).

0016 Mediterranean mandarin (C. deliciosa Tenore) is

also known as ‘Willowleaf’ and includes Avana

clones.

Lemons

0017 The lemon (C. limon [L.] Burm. f.) is an important

fresh fruit group in world markets. Even though they

are not eaten fresh, they are widely used for their acid

juice content and slices, and for processing. The main

cultivars are dual purpose and include Eureka,

Lisbon, Meyer (a hybrid), Fino, and Verna. A minor

related group of sweet or acidless cultivars and

hybrids also exists.

Limes

0018 Limes are also a varied group with a distinctive flavor

and aroma, consisting mainly of two broad sub-

groups:

0019 Acid limes are small fruited (C. aurantifolia Swing)

with West Indian, Mexican, or Key lime as the

main cultivar, and often also processed into cordial;

the large fruited (C. latifolia Tan) with Persian,

Tahiti, or Bearss the main cultivar, is normally

marketed as a fresh seedless fruit (Figure 2).

0020Sweet limes (C. limettioides Tan), also known as

the Palestine or Indian sweet lime, are insipid and

not normally attractive to Western palates.

Grapefruit

0021Grapefruit is one of the newer types (C. paradisi

Macfadyen) of citrus. It contains several distinct

groups according to the rind or flesh-colored pig-

ments:

0022Common or white fleshed, with Marsh (seedless)

the main cultivar.

0023Pigmented, where the older cultivars were con-

sidered ‘pink’-fleshed (with Thompson and Ruby

the main cultivars), while newer selections, muta-

tions or cultivars bred in the USA are now classified

as ‘red’-fleshed, due to the deeper pigmentation in

both the rind and flesh while also being seedless.

From this group, Star Ruby, Flame, and Rio Red are

becoming important in world markets (Figure 3).

A recent breeding program in California, where an

acidless pummelo was crossed with a white seedy

grapefruit, has resulted in the selection and release

of two new low-acid seedless grapefruit type cultivars

– Melogold and Oroblanco (also called ‘Sweetie’ in

Israel and some other countries).

Growing Regions and Conditions

0024Production regions are located in a wide range of

climatic conditions, including the humid tropics,

arid subtropics and intermediate climates. Commer-

cial production tends to be located in two narrow

belts in the subtropics and between 20 and 40



latitude north and south of the equator.

fig0002Figure 2 (see color plate 26) Limes are normally harvested for

fresh marketing when mature but with green or light green to

silver-colored rinds.

CITRUS FRUITS/Types on the Market 1331

0025 Citrus grows best in cooler, frost-free, Mediterra-

nean-type climates, provided that the soils are suit-

able and rainfall is at least 1200 mm, distributed

evenly throughout the year, or supplemented by irri-

gation. Climate can significantly affect yield, fruit

quality, and tree health. In particular, minimum tem-

peratures and degrees of frost restrict commercial

production within many countries of the world.

0026 Some cultivars have been bred or selected that

extend production into marginally cooler climates,

e.g., satsuma mandarins in Japan and China. Limes

and pummelos grow well in tropical areas, where the

normal rind color of oranges does not develop. High-

quality grapefruit tend to be grown in hot desert

areas.

Production Statistics

0027 Commercial citrus production has been recorded by

the FAO in over 100 different countries and through

out six regions – Africa, North America, South Amer-

ica, Asia, Europe (Mediterranean), and Oceania.

The world’s citrus production has been gradually in-

creasing through a 3-year average of 87 980 10

in 1995–1998, to a slightly smaller total crop of

82 166 10

t in 1998–1999, as shown in Table 1.

The production for the main types for 1998–1999

is shown in Figure 4. ‘Other’ citrus types totaled

only 5124 10

t, with the majority recorded in

Asia. The 4-year 1995–1999 production trends and

percentage of the main citrus types grown are shown

in Figure 5.

0028The largest growing areas are located in the

northern hemisphere, where 68% of world produc-

tion occurs, and include the important Mediterranean

region with 20%, e.g., Spain, Egypt, Italy and the

USA, China, and Mexico, whereas the southern hemi-

sphere (32%) includes the largest producer in the

world – Brazil, together with Argentina and South

Africa. Nonspecified areas of citrus production with

just over 16 000 10

t in 1998–1999 would mainly

occur in the subcontinent (especially India) and Asia.

0029Some regions like Japan, China, India, Mexico, and

Asia have important local or domestic markets for

their fresh citrus fruits, whereas others like Spain,

USA, South Africa, Morocco, Turkey, and Argentina

depend on exports as a major outlet for much of their

production. Table 1 indicates total world fresh fruit

exports of 11% in 1998–1999 for the main citrus

types and with FAO recording 92 countries exporting

some citrus.

0030In the two largest producing countries (Brazil and

the USA), there has been an increasing trend for a

large percentage of the production to be processed

into frozen concentrated orange juice for storage

and/or export throughout the world. The processing

of some citrus production in Spain, Argentina,

and Italy is also an important fresh juice market

(Figure 6). Overall, in 1998–1999, 27 664 10

were processed, or 34% of total citrus production

fig0003 Figure 3 (see color plate 28) A range of internal pigments are now available in grapefruit, with consumer interest in the newer red

fleshed cultivars (left to right: Marsh, Thompson, Rio Red, Flame, and Star Ruby).

tbl0001 Table 1 Fresh citrus crop production and utilization (with respective percentages), and the main producing countries of each for the

major types produced throughout the world in 1998–1999

Citrus type Totalproduction (10

t) % Exports (10

t) % Processed (10

t) % Main producing countries

Oranges 53 644 65 4 327 48 22 784 82 Brazil, USA, Mexico, Spain, China

Mandarins 14 463 18 2 191 24 1 206 5 China, Spain, Japan, Brazil, Korea

Lemons and limes 9 446 11 1 362 15 1 991 7 Argentina, Mexico, Brazil, Spain, Egypt

Grapefruit 4 614 6 1 135 13 1 682 6 USA, Israel, Cuba, China, Argentina

Total world 82 166 9 015 11 27 664 34 Brazil, USA, China, Spain, Mexico

1332 CITRUS FRUITS/Types on the Market

(Table 1), whereas Brazil is reported to have pro-

cessed 73% of their total orange production in

1989–1999, and the USA 88%.

Utilization of Lesser-Known Citrus Types

0031Some minor and lesser-known citrus fruit types

that have fresh or processing uses and have some

market importance in different countries or regions

of the world are listed in alphabetical order. In

many situations, local names exist for some of these

types.

Bergamot (

C. bergamia

Risso)

0032This appears to be a variant of the sour orange and is

mainly grown for its unique aromatic rind oil or

essence in the coastal region of Calabria, a province

of Italy. This essence is widely used in the food trade

and in confectionery, and as an aroma for liqueurs,

teas, sweets, and candied fruit.

Calamondin (

C. madurensis

Loureiro)

0033This resembles the mandarin and is grown extensively

in the Orient, China, Taiwan, Japan, and the Philip-

pines (where it is known as the ‘Calamonding’ or

‘Kalamansi’). The fresh fruit is sour but is widely

used for processing and as an ornamental tree.

Citrons (

C. medica

L.)

0034Like the other members of the acid group of lemons

and limes, these also have two classes, the acid and

the sweet, each with several cultivars. Citron are

principally used for candied peel, but the etrog citron

is also used in Jewish religious ceremonies. The

Fingered Citron or Buddha’s Hand, has an unusual

appearance, with a distinctive and pervasive aroma,

fig0006 Figure 6 Juicing of oranges into various products is an import-

ant market in many countries. Fresh juice and citrus drinks are

normally sold in consumer convenience packs.

Greece

South Africa

Morocco

Japan

Turkey

Italy

Argentina

Egypt

Mexico

Spain

China

USA

Brazil

Rest of World

0 100005000 15 000 20 000 25 000

'000 tonnes

fig0004 Figure 4 World citrus production, 1998–1999 for major producers and the rest of the world (which includes Cuba, Israel, Australia,

Venezuela, South Korea, Lebanon, Uruguay and Cyprus).

Grapefruit

Lemons/limes

11%

Mandarins

17%

Oranges

66%

fig0005 Figure 5 (see color plate 27) Average production percentages

for the main citrus types grown in the world between 1995 and

1996 and between 1998 and 1999.

CITRUS FRUITS/Types on the Market 1333

and is also used in religious ceremonies, perfuming

rooms, and clothing for its medicinal values, and

serves to highlight fruit-bowl arrangements.

Kaffir Lime (

C. hystrix

DC)

0035 This belongs to the subgenus Papeda and is not a true

‘lime,’ but as the Kaffir lime is widely grown in Thai-

land, Philippines, Malaysia, Indonesia, and generally

throughout Asia. It has unusual looking leaves

(having a large winged petiole, see Figure 7) that are

used (fresh or dried) with the fruit rind (as the fruit is

normally not eaten) as a seasoning, flavoring, and

garnishing in Asian food or recipes.

Kumquats (

Fortunella

spp.)

0036 Also known as ‘cumquats,’ these are the smallest of

the true citrus fruits. They can be eaten as fresh fruit

or marmalade, or can be brandied. Several distinct

cultivars that bear edible fruits are known:

0037 Nagami or oval kumquat (F. margarita [Lour.]

Swing)

0038 Marumi or round kumquat (F. japonica [Thumb.]

Swing)

0039 Meiwa or large round kumquat (F. crassifolia

Swing).

Several minor kumquats are also grown mainly for

ornamental purposes, e.g., Hong Kong (F. hindsii

Swing) and Malayan (F. polyandra Tan).

Pummelo (

C. grandis

[L.] Osbeck)

0040 This is also known as ‘shaddock’ or ‘pomelo’ and

is the largest of the citrus fruits. Because pummelo

hybridizes very readily, this has resulted in acid, acid-

less or sweet, pigmented or nonpigmented flesh, seedy

or seedless cultivars being grown. This citrus type is

common in some Asian countries, e.g., Thailand,

China, and Indonesia, but is not common in Western

countries or in world markets. It is usually eaten as a

spooned desert fruit.

Sour oranges (

C. aurantium

L.)

0041Also known as bitter oranges, sour oranges are nor-

mally used for processing (marmalade or rind oil to

flavor soft drinks and liqueurs). Most cultivars can be

classified into three groups:

0042Common, bitter, or sour oranges, of which the

Seville (rough or smoothed skinned) is the most

important.

0043The bittersweet orange is a subgroup of the above

common sour orange but has a lower acidity and

better flavor.

0044Variant bitter oranges or Bouquetiers are an

important perfumery cultivar.

Conclusion

0045Many types of citrus fruits and processed products

are now widely available throughout the world from

local production or importation to supplement local

supplies or in non-producing countries. Citrus is

mainly consumed as fresh fruit, with their distinctive

refreshing appeal and flavor, while also being a

healthy, enjoyable, convenient and nutritious food.

The fruit is also an excellent source of vitamins,

minerals, dietary fiber and still low in kilojoules.

Some fruit are used extensively to garnish food,

while many processed products especially juices, cor-

dials and marmalades are also widely available and

consumed.

See also: Ascorbic Acid: Properties and Determination;

Physiology; Citrus Fruits: Composition and

Characterization; Processed and Derived Products of

Oranges; Jams and Preserves: Methods of Manufacture;

Chemistry of Manufacture