CITRUS FRUITS | Types on the Market

CITRUS FRUITS/Types on the Market 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 B6: Properties and Determination; Zinc: Physiology

Further Reading Bitsch I (1983) Perspektiven der Alkoholforschung. Erna¨hrungs-Umschau 30: 132–135. Bitsch R (1987) Alkohol und Vitaminstoffwechsel. Erna¨hrungs-Umschau 34: 161–166. Eriksson K, Sinclair JD and Kiianmaa K (eds) (1980) Animal Models in Alcohol Research. London.

Citric Acid Cycle

1329

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: neuropathological observations. Acta Medica Scandinavica Supplementum 717: 47–54. Victor M, Adams RD and Collins GH (1989) The Wernicke–Korsakoff Syndrome, 2nd edn. Philadelphia. Ziegler EM and Filer LJ (eds) (1996) Present Knowledge in Nutrition, 7th edn. Washington, DC: ILSI.

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 Copyright 2003, Elsevier Science Ltd. All Rights Reserved.

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 conditions, production statistics, with the utilization of the main and also lesser known types are discussed.

Classification 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

The 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

0002

1330 CITRUS FRUITS/Types on the Market

0003

0004

fruit crop, also has countless local names and identities throughout the world, often for an identical cultivar. Citrus trees belong to the plant family Rutaceae, subfamily Aurantioideae, which comprises 33 wellknown and described genera and 203 species. In addition, 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. 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

0006

0007

0008

Citrus fruits are principally marketed according to how they are consumed: 1. As fresh or dessert fruits – sweet oranges, mandarins (eaten out of hand), grapefruit, or pummelo (spooned). Juice, slices, segments, rind, and leaves are also used to garnish food. 2. 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 specialized types are also candied, dried, or used for marmalade manufacture. (See Citrus Fruits: Composition and Characterization; Processed and Derived Products of Oranges.)

production. The many known cultivars can be subdivided into three main groups as the acidless or sugar oranges do not contribute to world trade: . Common 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. . Navel 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 Newhall) 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. . Blood 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.

0010

0011

0012

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

Figure 1 (see color plate 25) Navels are the most important sweet, juicy, and seedless orange marketed for fresh fruit consumption.

fig0001

CITRUS FRUITS/Types on the Market

1331

Mandarins 0013

0014

0015

0016

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. . 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. . Common mandarins (C. reticulata Blanco) are a very extensive group of different cultivars widely grown and available in world markets, e.g., Imperial, 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 Seminole). . 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.

Figure 2 (see color plate 26) Limes are normally harvested for fresh marketing when mature but with green or light green to silver-colored rinds.

Tahiti, or Bearss the main cultivar, is normally marketed as a fresh seedless fruit (Figure 2). . Sweet limes (C. limettioides Tan), also known as the Palestine or Indian sweet lime, are insipid and not normally attractive to Western palates.

fig0002

0020

Grapefruit

Grapefruit is one of the newer types (C. paradisi Macfadyen) of citrus. It contains several distinct groups according to the rind or flesh-colored pigments: . Common or white fleshed, with Marsh (seedless) the main cultivar. . Pigmented, where the older cultivars were considered ‘pink’-fleshed (with Thompson and Ruby the main cultivars), while newer selections, mutations 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).

0021

0022

0023

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).

Limes 0018

0019

Limes are also a varied group with a distinctive flavor and aroma, consisting mainly of two broad subgroups: . 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,

Growing Regions and Conditions Production regions are located in a wide range of climatic conditions, including the humid tropics, arid subtropics and intermediate climates. Commercial production tends to be located in two narrow belts in the subtropics and between 20 and 40
latitude north and south of the equator.

0024

1332 CITRUS FRUITS/Types on the Market

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

0025

0026

Citrus type

Totalproduction ( 103 t) %

Exports ( 103 t) %

Processed ( 103 t) %

Main producing countries

Oranges Mandarins Lemons and limes Grapefruit Total world

53 644 65 14 463 18 9 446 11 4 614 6 82 166

4 327 2 191 1 362 1 135 9 015

22 784 82 1 206 5 1 991 7 1 682 6 27 664 34

Brazil, USA, Mexico, Spain, China China, Spain, Japan, Brazil, Korea Argentina, Mexico, Brazil, Spain, Egypt USA, Israel, Cuba, China, Argentina Brazil, USA, China, Spain, Mexico

48 24 15 13 11

Citrus grows best in cooler, frost-free, Mediterranean-type climates, provided that the soils are suitable and rainfall is at least 1200 mm, distributed evenly throughout the year, or supplemented by irrigation. Climate can significantly affect yield, fruit quality, and tree health. In particular, minimum temperatures and degrees of frost restrict commercial production within many countries of the world. 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. Highquality 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 America, Asia, Europe (Mediterranean), and Oceania. The world’s citrus production has been gradually increasing through a 3-year average of 87 980  103 t in 1995–1998, to a slightly smaller total crop of 82 166  103 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  103 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. The largest growing areas are located in the northern hemisphere, where 68% of world production occurs, and include the important Mediterranean region with 20%, e.g., Spain, Egypt, Italy and the USA, China, and Mexico, whereas the southern hemisphere (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  103 t in 1998–1999 would mainly occur in the subcontinent (especially India) and Asia. Some 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. In 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  103 t were processed, or 34% of total citrus production

0028

0029

0030

CITRUS FRUITS/Types on the Market

1333

Greece South Africa Morocco Japan Turkey Italy Argentina Egypt Mexico Spain China USA Brazil Rest of World 0

5000

10 000

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).

Lemons/limes 11%

Utilization of Lesser-Known Citrus Types

Grapefruit 6%

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.

Some 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.

0031

Bergamot (C. bergamia Risso)

This 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.

0032

Calamondin (C. madurensis Loureiro)

This resembles the mandarin and is grown extensively in the Orient, China, Taiwan, Japan, and the Philippines (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.

0033

Citrons (C. medica L.) fig0006

Figure 6 Juicing of oranges into various products is an important market in many countries. Fresh juice and citrus drinks are normally sold in consumer convenience packs.

(Table 1), whereas Brazil is reported to have processed 73% of their total orange production in 1989–1999, and the USA 88%.

Like 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,

0034

1334 CITRUS FRUITS/Types on the Market Sour oranges (C. aurantium L.)

Also known as bitter oranges, sour oranges are normally used for processing (marmalade or rind oil to flavor soft drinks and liqueurs). Most cultivars can be classified into three groups:

fig0007

Figure 7 Fresh or dried Kaffir lime leaves are an important garnish in many Asian recipes. (Market packaged dried leaves (L) and freshly picked leaves showing their distinctive shape (R) ).

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 Thailand, 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

0037

0038

0039

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: . Nagami or oval kumquat (F. margarita [Lour.] Swing) . Marumi or round kumquat (F. japonica [Thumb.] Swing) . 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, acidless 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.

. Common, bitter, or sour oranges, of which the Seville (rough or smoothed skinned) is the most important. . The bittersweet orange is a subgroup of the above common sour orange but has a lower acidity and better flavor. . Variant bitter oranges or Bouquetiers are an important perfumery cultivar.

0041

0042

0043

0044

Conclusion Many 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, cordials 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

Further Reading Cottin R (coordinator) (1997) Citrus of the World A Citrus Directory. San Giuliano, France: SRA INRA-CIRAD. FAO (1999) Citrus Fruit Fresh and Processed, Annual Statistics, Tables 1–10 and 16–20. Rome: Food and Agriculture Organization. Reuther W, Webber HJ and Batchelor LD (eds) (1967) The Citrus Industry, vol. 1. Berkley, CA: University of California. Saunt J (1990) Citrus Varieties of the World. Norwich, UK: Sinclair International. Sinclair WB (1984) The Biochemistry and Physiology of the Lemon and other Citrus Fruits, pp. 711–718. Berkley, CA: University of California. Swingle WT and Reece PC (1967) The Botany of Citrus and its Wild Relatives. In: Reuther W, Webber HJ and Batchelor LD (eds), vol. 1. The Citrus Industry. Berkley, CA: University of California.

0045

CITRUS FRUITS/Composition and Characterization Young RH (1986) Fresh Citrus Cultivars. In: Wardowski WF, Nagy S and Grierson W (eds), pp. 110–125. Fresh Citrus Fruits. Westpoint, CT: AVI Publishing. USDA (1999) World Fresh Citrus Situation. In: World Horticultural Trade and US Export Opportunities, Circular Series FHORTH, pp. 18–32. USA: Foreign Agricultural Service.

Composition and Characterization L Izquierdo, Formerly of Consejo Superior de Investigaciones Cientı´ ficas, Valencia, Spain J M Sendra, Instituto de Agroquı´ mica y Technologı´ a de Alimentos, Valencia, Spain This article is reproduced from Encyclopaedia of Food Science, Food Technology and Nutrition, Copyright 1993, Academic Press.

Introduction 0001

0002

0003

0004

Citrus fruits are one of the largest fruit crops in the world. About 30% of citrus fruits is processed to obtain various products, mainly juice. Similarly, the citrus industry is also the second largest fruitprocessing industry, surpassed again by the grape industry, which mainly produces wine. Neither orange juice nor wine can be considered essential foods but they do have an important role in our lives. Although citrus fruits have been consumed since ancient times, citrus processing, as it is known today, was not possible until thermal treatment (to inactivate enzymes and microorganisms) and concentration processes were commercially available. Since then, the citrus industry has developed rapidly, becoming prominent among food industries. Although consumption of fresh citrus fruits is popular in all producing countries, processed products must still be considered almost as luxury products. Breakfast with orange juice is only common in developed countries. Thus, citrus industries process value-added products whose quality, nutritional characteristics, and purity are appreciated. Since these three aspects are closely related to composition, the analysis of citrus constituents is a frequent subject of research work, supported by governments and industries. This article covers the most important aspects of citrus fruit composition, its relationship to nutritional value, and its importance for product authentication. Several books have been published on these subjects and the Further reading section lists some of them as well as published composition tables.

1335

Constituents The genus Citrus has many species and the differences among them are of great interest to specialists. However, from a general point of view, the similarities are greater than the differences, which is not surprising when considering species of the same genus. The economic importance also differs among species and compositional studies of the main species are more frequent. Thus, data from Citrus sinensis (sweet orange) are more extensive than from C. reticulata (tangerine), C. limon (lemon), or C. paradisi (grapefruit), and data from these species are more comprehensive than from other Citrus species. Within each species some varieties are better known than others. Valencia orange is the best-studied sweet orange, since it is the most important variety for juice extraction, the main citrus product. Thus, most information given here will refer to the juice rather than to the fruit, since juice, accounting for about half of the total weight of an orange, is the most important part of the fruit, and is the part of the fruit mainly consumed by humans. Orange peel constitutes most of the other half of the fruit, but peel is of much less importance than juice. Although some byproducts (cattle feed, molasses) are obtained from peel, it is more a question of removing residues and avoiding pollution than of economic interest. Only peel oil (obtained before or during juice obtention) and pectins (obtained only from suitable species and varieties) are important peel products for human consumption, perfumery, and cosmetics. Our knowledge of the chemical composition of juice and fruits is being continuously improved. The efficiency of instrumental methods of analysis allows the rapid identification of more and more minor constituents. But the basic major constituents have been well known since the application to citrus research of classical methods of analysis, which are still of interest for some rapid determinations. Both types of methods will be considered in this article, but it must be pointed out that analysis is a dynamic discipline and methods (mainly instrumental) are continuously being improved. Many of those which seem almost perfect today will look old-fashioned tomorrow. Citrus fruit parts are represented schematically in Figure 1, and the approximate constitution of oranges is shown in Table 1. Juice vesicles, located in the endocarp, contain the juice, which constitutes about 50% of the total weight of a typical orange fruit. The peel is formed by the flavedo (epicarp and outer mesocarp) and the albedo (inner mesocarp). Flavedo and albedo account, respectively, for about 10 and

0005

0006

0007

0008