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

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charqui texture, and the shear force increases expo-

nentially with water loss.

Nutritive Value Evaluation

0021 Cured meat products have the disadvantages of the

presence of nitrosamine that is formed during curing.

This compound is a potent carcinogenic component

and has been detected in bacon after frying. On the

other hand, because of the high biological value of

protein, they present a high nutritive value. This is the

case for intermediate-moisture meat such as charqui

meats. Recent experiments with cooked samples have

demonstrated high protein efficiency ratio of 2.07

and net protein utilization of 87.7, which is close to

those of casein: 2.33 and 94.6, respectively.

Carcass reception

Deboning

Brine

20% NaCl

Restack

Washing

Drying under the sun

Charqui ready

Packaging

Marketing

fig0001 Figure 1 Flow diagram showing charqui meat processing with pictures of the steps of deboning, stacking, drying under the sun, and

packaging. Photos courtesy of Industrias Allyson, Santana da Parnaı

ba, Brazil.

1706 CURING

Fermentation

0022 Fermentation is an old technology applied to meat

products that has a preservative activity and also

gives rise to specific products with characteristic

flavors. Initially, the type of microorganism was

naturally selected; today there is an enormous tech-

nological advance with the application of starter cul-

tures. In this way, a quicker and more uniform

product can be obtained. In general, starter can be

be used in two ways: maturation and surface. Lacto-

bacillus, Pediococcus, Micrococcus, and Staphylo-

coccus normally represent maturation starters.

Lactobacillus and Micrococcus are characterized by

the production of lactic acid which brings down the

pH from 5.7–6.2 to as low as 5.3, with some pro-

cesses dropping to pH 4.6: this is important for the

reduction of nitrite to nitrous acid. The presence of

Micrococcus and Staphylococcus is also important

because they are capable of reducing nitrate to nitrite.

In general, fermented meat products can be divided

into two major groups: products using whole-meat

pieces such as country ham products and charqui

meats; and products using small chopped meat (the

most representative quantitatively), as fermented

sausage with various types of salami.

Microbiological Safety

0023It is known that curing processing inhibits the

development of deteriorating bacteria. It follows the

application of the so-called hurdle technology theory,

that involves the application of sequential hurdles.

Thus, nitrite would inhibit several kinds of bacteria,

but Gram-positive bacteria, i.e., Lactobacillus and

Micrococcaceae, are more resistant and play a rele-

vant role in fermentation. Therefore nitrite has the

important function of selecting microflora in particu-

lar in fermented sausages. The most important role,

though, is to inhibit the development of Clostridium

botulinum. Salt quantity and the resultant water

activity inhibit the bacterial outgrowth, including

the enterogenic Staphylococcus aureus.

Denatured metmyoglobin

Brown

∆

Reduced

ReducedOxidized

Nitric oxide

Oxymyoglobin

Bright red

Hemin

Oxidation

Hemo + Globin

Myoglobin

Purple red

Nitric oxide myoglobin

Bright pink

Nitrosohemochrome − stable pink

∆

pH > 5

pH < 5

−O

Metmyoglobin

Brown

Nitrosylmetmyoglobin

Brown

fig0002 Figure 2 (see color plate 41) Changes in the pigment heme during curing and respective color and iron state.

CURING 1707

Public Health Concern for Cured Meats

0024 Nitrosamine as a carcinogenic agent is a worldwide

concern, therefore its quantity is limited for curing.

The amount of 120 p.p.m. is permitted to process

bacon in USA, although 40–80 p.p.m. of residual

nitrite level is sufficient to inhibit C. botulinum

spore outgrowth. In Europe an estimated maximum

level of 150 p.p.m. for sodium nitrite is permitted for

cured meat. This quantity varies depending on the

type of products and also on the processing tech-

nique. Sodium nitrate is not allowed in bacon and is

only permitted to be used in dry-cured meat whilst

nitrite is applied in the wet-curing processes. In South

America, a level of 200 p.p.m. is allowed for cured

meat products and 50 p.p.m. for cured charqui meats.

See also: Antioxidants: Natural Antioxidants; Synthetic

Antioxidants; Fermented Foods: Fermented Meat

Products; Nitrosamines; Phosphorus: Properties and

Determination

Further Reading

Campbell-Platt G (1995) Fermented meats – a world per-

spective. In: Campbell-Platt G and Cook PE (eds) Fer-

mented Meats, pp. 39–52. London: Chapman & Hall.

Cassens RG, Greaser ML, Ito T and Lee M (1979) Reac-

tions of nitrite in meat. Food Technology 17: 46–62, 93.

Chang SF, Huang TC and Pearson AM (1996) Control of

the dehydration process in production of intermediate-

moisture meat products: a review. Advance in Food

Nutrition and Research 39: 71–161.

Flores J and Toldra

F (1993) Curing. In: Macrae R, Robin-

son RK and Sadler MJ (eds) Encyclopaedia of Food

Science, Food Technology and Nutrition, pp. 1277–

1282. London: Academic Press.

Leistner L (1995) Stable and safe fermented sausages world-

wide. In: Campbell-Platt G and Cook PE (eds) Fer-

mented Meats, pp. 160–175. London: Chapman & Hall.

Sebranek JG and Cassens RG (1973) Nitrosamines: a

review. Journal of Milk and Food Technology 36: 76–91.

CURRANTS AND GOOSEBERRIES

N Heiberg, The Norwegian Crop Research Institute,

Leikanger, Norway

F Maage, Agricultural University of Norway, Aas,

Norway

Background

0001 The domestication of currants and gooseberries has

taken place within the last 400 or 500 years. Horti-

culturally, these fruits are not major crops, but they

are widely grown in northern European regions. The

crop is mainly used in the production of juices,

jams, and jellies. Blackcurrant has strong color and

aromatic taste, and is an excellent source of ascorbic

acid. Long before vitamins were known, people used

blackcurrants for medical purposes, mostly as a hot

drink against the common cold.

Global Distribution

0002 The genus Ribes of the Saxifragaceae family, consists

of about 150 species of currant and gooseberry,

mainly distributed in the northern temperate regions

of Europe and North America. Of the edible types,

the main commercially grown species are black-

currant (Ribes nigrum L.) red- and whitecurrants

(R. rubrum L., R. sativum Syme, and R. petraeum

Wulf.), and the gooseberry (R. grossularia L.).

Commercial Importance

0003The majority of currants and gooseberries are pro-

duced in Europe (Table 1) with Germany, Russia, and

tbl0001Table 1 World production of Ribes fruit (10

kg)

1988 1998

Austria 29 19

France 9 10

Germany 173 136

Netherlands 1 2

Scandinavia 24 24

UK 21 10

Western Europe 263 208

Czechoslovakia 35

Czech Republic 20

Hungary 18 12

Poland 165 175

Slovakia 4

Eastern Europe 218 211

USSR 100

Russian Federation 204

Ukraine 18

New Zealand 2 4

World 583 650

From Food and Agriculture Organization (FAO) production year books.

1708 CURRANTS AND GOOSEBERRIES

Poland as the main producers. Blackcurrants account

for more than half of the total world production; this

species is dominant in the UK, Scandinavia, and New

Zealand, and is gaining importance in other coun-

tries. About a quarter of Ribes production is goose-

berry, but the production of this fruit is decreasing in

most countries. Germany, the UK, Poland, Czech

Republic, and Russia are the major gooseberry-

producing countries. Countries with a high propor-

tion of redcurrant compared with blackcurrants are

Germany, Belgium, The Netherlands, and Austria.

Currants and gooseberries are at present of little com-

mercial significance in North America, as they are

alternative hosts of white blister rust (Cronartium

ribicola Fisch.), but there is increasing interest in

Ribes fruits in the USA, and some legislative controls

on their cultivation are changing.

0004 Machine harvesting is prevalent in industrial pro-

duction of blackcurrants. The machines may be used

for redcurrants as well but work less satisfactorily for

gooseberries.

0005 Besides commercial production, currants and

gooseberry are important home garden crops in many

countries. They tolerate both low summer and winter

temperatures and therefore may be grown far to the

north, where few other fruits can be cultivated.

Blackcurrant Cultivars

0006 Old cultivars such as Roodknop and Øjebyn are still

grown in Europe, but the ‘Ben’ cultivars from the UK

have been commercially successful in many countries

and their hectarage is increasing. Ben Lomond has

been dominant so far, but in most countries, there is

a swing towards newer cultivars like Ben Alder and

Ben Tirran. The main cultivar in New Zealand has

been Magnus, but north European cultivars such as

Ben Ard and Ben Rua are becoming more widespread

there. In the expanding Polish hectarage, Titania,

Roodknop, Ben Lomond, and Ben Nevis are popular

besides the traditionally grown Øjebyn. Russia has a

large range of cultivars adapted to the climatic condi-

tions in the different regions. Breeders are working on

blackcurrants in several countries, and new cultivars

are released yearly.

Red- and Whitecurrant Cultivars

0007 The major red cultivars grown in Europe are Jonk-

heer van Tets, Red Dutch, Rondom, and Stanza. Red

Dutch is winterhardy and is widely grown in the

most northern areas. For the fresh fruit and dessert

markets, Red Lake and Jonkheer van Tets have

been popular because of their good eating quality.

However, more recent cultivars from Holland,

Rovada, Rolan, Rosetta, and Rotet, and Junifer

from France, are gaining in popularity. White Dutch

and White Versailles are most widespread among the

whitecurrant cultivars. The whitecurrants lack red

pigments and are in fact a color form of redcurrants.

Gooseberry Cultivars

0008In the nineteenth century, gooseberry was a popular

fruit in home gardens in Europe, especially in the UK,

and amateur breeders raised hundreds of cultivars.

Selection was mainly for fruit size. However, the

appearance of American gooseberry mildew (Sphaero-

theca morsu

vae) in 1905 soon drastically reduced the

acreages of gooseberry, as the large-fruited types all

proved more or less susceptible.

0009Mildew-resistant cultivars have been released, but

so far, they have been inferior to the old types in terms

of both fruit size and quality. One that is gaining

popularity is Invicta from the UK. Among the old,

nonresistant cultivars, the green-fruited cultivar

Whitesmith and the red-fruited Whinham’s Industry

are still grown. New cultivars such as Greenfinch and

Pax from the UK, and Rixanta, Rokula, Reflamba,

and Rolanda from Germany have been widely tested.

Other

Ribes

Cultivars

0010Artificial hybridization between R. nigrum, R. divar-

icatum,andR. grossularia has given rise to the new

species Ribes nidigrolaria. The fruit quality is some-

where between blackcurrant and gooseberry. Josta,

the first cultivar to be released from Germany, is

planted mostly in home gardens.

Morphology and Anatomy of the Fruit

0011The fruits of currants and gooseberry are true berries

with the seeds enclosed in a fleshy pericarp. The

berries are born in clusters, with every single fruit

adjoined to the main strig by a short stem. The fruits

ripen in order along the strig, the fruit closest to the

branch first and the terminal last. The fruit closest to

the branch is largest, and the fruit in the end of the

strig is smallest. Gooseberry fruits develop singly or in

small clusters with two or three fruits, the distal fruit

often being smaller than the others. The fruits on the

plant are harvested at the same time, often mechanic-

ally. At harvest, the stem follow the fruit, and in the

tbl0002Table 2 Fruit characteristics of currants and gooseberry

Characteristics Blackcurrant Redcurrant Gooseberry

Number of fruits per strig 5–10 6–14 1–3

Fruit weight (g) 0.7–1.4 0.4–0.9 1.5–15.0

Number of seeds per fruit 30–50 5–11 10–45

Weight per seed (mg) 1–2 6–8 4–6

From Maage F (unpublished).

CURRANTS AND GOOSEBERRIES 1709

distal end, the rest of the flower is found. Table 2 lists

the range of variation concerning fruit characteristics.

Gooseberry has the largest fruits with a great variation

between cultivars, redcurrant being the smallest. Red-

currants have the lowest number of seeds and the

largest seeds of the berries. The skin of some goose-

berry cultivars is hairy, whereas the skin of currants is

always hairless.

0012The pigments of the blackcurrant fruit are located

in the skin, the flesh remaining green. The pigment of

redcurrants and gooseberries, however, is also present

to some extent in the fruit flesh. Unlike currants, the

cultivars of gooseberry cover the whole range of fruit

colors, from dark to light red, through various shades

of green, yellow, and almost white. Blackcurrants

have a dark purple color, whereas redcurrants are

pure red. The white currants are lacking antho-

cyanins and have a light yellow–greenish color.

Chemical and Nutritional Composition

0013The energy in fruits of currants and gooseberries

comes mainly from carbohydrates (Table 3). Only a

small part comes from protein and fat. Fructose and

glucose are the main sugars, with roughly equal

amounts of each (Table 4). Sucrose is present, but to

a lesser extent. Gooseberries contain small amounts

of sorbitol, whereas only traces of sorbitol are present

in currants. A characteristic feature of the fruits is the

high content of acids. Citric acid is predominant in

currants, whereas citric acid and malic acid are

present in almost equal quantities in gooseberries.

0014Ascorbic acid (vitamin C) has probably received

more attention than any other constituent of

blackcurrants. Less than 50 g of the fruit meets the

tbl0003 Table 3 Chemical composition (per kilogram of fresh fruit) of

currants and gooseberry

Nutrient Blackcurrant Redcurrant Gooseberry

Water (g) 815 845 880

Carbohydrates (g) 128 96 78

Protein(g) 13 12 8

Fat (g) 2 2 2

Fiber (g) 43 39 22

Pectin (g) 8 7 5

Total sugar (g) 85 57 56

Energy (kJ) 2600 2050 1650

Energy (kcal) 621 490 395

Sodium (mg) 17 14 15

Potassium (mg) 3100 2300 1600

Manganese (mg) 3 2 10

Magnesium (mg) 190 140 115

Calcium (mg) 550 380 250

Iron (mg) 13 9 6

Phosphorus (mg) 480 330 250

Copper (mg) 1 1 2

Zinc (mg) 3 2 2

Ash (mg) 7200 6400 4800

Ascorbic acid (mg) 1600 650 440

Thiamin (mg) 0.5 0.4 0.4

Riboflavin (mg) 0.4 0.3 0.2

Pyridoxine (mg) 1.2 0.5

Nictinic acid (mg) 2.8 2.5 2.5

Pantothenic acid (mg) 4.0 6.0 2.3

b-Carotene (mg) 1.2 0.6 1.5

Vitamin B

0.8 0.5 0.2

Folic acid (mg) 0.2 0.1 0.2

From Green A (1971) Soft fruits. In: Hulme AC (ed.) Biochemistry of Fruits

and their Products, vol. 2, pp. 375–410. London: Academic Press; Herrmann

K (1997a) Inhaltsstoffe der Johannisbeeren. Die industrielle Obst- und

Gem

severwertung 82(1): 14–20; Herrmann K (1997b) Inhaltsstoffe der

Stachelbeeren. DieindustrielleObst-undGem

severwertung 82(2): 34–36;

Kuusi T (1970) Uber die chemische Zusammensetzung und Kennzahlen

einiger finnischer einheimischer Beeren. Fl

ssiges Obst. 37: 188–190,

253–263; Souci SW and Bosch H (1978) Lebensmittel-Tabellen f

rdie

N'hrwertberechnung. Stuttgart: Wissenschaftliche Verlagsgesellschaft.

tbl0004 Table 4 Some organic characteristics in fruit juice (per kilogram of fresh juice) of Ribes: mean values and variation

Characteristic Blackcurrant Redcurrant Gooseberry

Soluble solids (g) 160 (120–200) 105 (80–145) 128 (80–170)

Glucose (g) 35 (30–45) 26 (7–35) 38 (16–52)

Fructose (g) 38 (34–46) 26 (18–31) 42 (21–52)

Sucrose (g) 13 (8–20) 4 (1–6) 12 (2–28)

Total sugar (g) 86 (74–105) 57 (32–68) 92 (48–112)

Titratable acids

(g) 39 (22–56) 24 (17–36) 23 (12–32)

Citric acid (g) 42 (32–55) 25 (15–38) 12 (8–14)

Malic acid (g) 6 (3–10) 5 (1–18) 14 (6–21)

pH 2.87 (2.68–3.18) 3.04 (2.86–3.20) 3.00 (2.79–3.06)

Acid content measured using equivalent weight of citric acid.

From Dietrich H, Kru

ger E, Patz C-D and Scho

pplein E (2000) Characterisierung von Schwartzen Johannisbeersorten im Hinblick auf die Saft- und

Nektarherstellung. Obst-, Gem

se- und Kartoffelverarbeitung 85(2): 86–98; Heiberg N, Ma

ge F and Haffner K (1992) Chemical composition of ten

blackcurrant (Ribes nigrum L.) cultivars. Acta Agriculturae Scandinavica, Section B, Soil and Plant Sci. 42: 251–254; Herrmann K (1997) Inhaltsstoffe der

Johannisbeeren. Die industrielle Obst- und Gem

severwertung 82(1): 14–20; Herrmann K (1997) Inhaltsstoffe der Stachelbeeren. Die industrielle Obst- und

Gem

severwertung 82(2): 34–36; Ma

ge F (1993) Vegetative, generative and quality characteristics of four blackcurrant (Ribes nigrum L.) cultivars.

Norwegian Journal of Agricultural Sciences 7: 327–332.

1710 CURRANTS AND GOOSEBERRIES

recommended daily requirement of ascorbic acid.

However, considerable variation exists between culti-

vars. Other vitamins are also present in the fruits, and

the content of minerals is also worth mentioning,

especially the high content of potassium.

0015 Attention is now being focused on naturally occur-

ring antioxidants. Besides ascorbic acids, currants,

especially blackcurrants, contain many substances

that have an antioxidant activity. Blackcurrants pos-

sess a high flavonoid content compared with other soft

fruits. The most important group of the flavonoids is

the anthocyanins. The anthocyanins are the dominant

pigments, and blackcurrants contain from 1250 to

2000 mg per kilogram of fresh weight. The anthocya-

nins of blackcurrant are mainly cyanidin and delphi-

nidin 3-glucosides and 3-rutinosides. In redcurrant,

six different cyanidin glycosides have been isolated.

Most red European gooseberry cultivars contain only

cyanidin 3-glucoside and 3-rutoniside. Another im-

portant group of flavonoids is the flavonols, of

which glycosides of kaemferol, quercetin and myrici-

tin are present in currants and gooseberries.

0016 The characteristic aromatic compounds of black-

currant are present in the whole plant. Several studies

have been carried out to identify the aromatic compon-

ents of blackcurrants, and a wide range of volatile

components have been identified, but the exact chem-

ical nature of the specific aroma in blackcurrants is

unknown.

0017The degree of ripening has a great influence on the

quality characteristics. The color intensity, content of

dry matter, soluble solids, and sugars increase with

ripening, whereas the viscosity and content of ascor-

bic acids decrease. The content of titratable acids

reaches its peak about 2 weeks before harvest and

changes little during ripening. The development of

some quality factors is shown in Figure 1.

0018The seeds of currants and gooseberry contain

about 20% fat, of which 5–20% is g-linolenic acid,

with the highest content occurring in blackcurrant.

Handling and Storage

0019The strong flavor and the high acidity of currants,

especially blackcurrants, make them less attractive

for fresh consumption. However, in Europe, there is

a market for fresh fruits, especially red currants, which

are used for desserts and decoration purposes. With a

combination of out-of-season production and storage

under controlled-atmosphere conditions, growers are

able to market fresh fruits most of the year. Goose-

berries have a milder flavor, and a considerable part of

the crop is used for dessert purposes. Gooseberries are

sold both as unripe, green fruits and as ripe fruits.

0020For fresh consumption, the Ribes fruits are still

picked by hand, because harvesting machines reduce

the postharvest quality. The currants are picked on

strigs, whereas gooseberries are sold as single fruits.

The berries should be picked in a dry condition, as

they spoil quickly if gathered and packed when wet.

0021Compared with many other soft fruits, currants

and gooseberries keep reasonably well, but without

cooling, the fruits decay rapidly after harvest. The

weight loss may reach 2–3% within 24 h without

cooling. The fruits are usually cooled to 0–5



C im-

mediately after harvest. Forced-air cooling is recom-

mended. At low temperatures, the blackcurrants have

a shelf-life of 2–6 days and redcurrants 2–4 weeks,

dependent on maturity stage. Picking the berries

slightly unripe increases the shelf-life. The fruits

should be kept cooled during transportation and

marketing. To increase the shelf-life, the fruits must

be stored in a controlled atmosphere, in which it is

possible to store blackcurrants for 3–4 weeks, goose-

berries for 6–8 weeks, and redcurrants for 8–14 weeks.

Industrial Uses

0022The most important products of blackcurrant are

different types of juices and syrups. Most of the UK

crop is used to produce the proprietary brand name

drink ‘Ribena.’ Owing to the special aromatic taste,

and the high content of ascorbic acid, blackcurrant

products are popular in northern Europe and are

8.0

−28 −21−14 −7

+7+14+21 −28 −21−14 −7

+7+14+21

10.0

12.0

14.0

16.0

18.0

2.0

3.0

4.0

5.0

0.1

0.2

0.3

0.4

0.5

0.6

8.0

10.0

12.0

14.0

16.0

18.0

2.0

3.0

4.0

5.0

0.1

0.2

0.3

0.4

0.5

0.6

Sampling date

Soluble solids (%) Titratable acids (%) Optical density at 520 nm

Blackcurrants Redcurrants

1% juice 5% juice

fig0001 Figure 1 Changes in fruit quality components in black- and

redcurrants from 28 days before to 21 days after normal harvest

time (titratable acid expressed in terms of citric acid). From Ma

F and Heiberg N (unpublished).

CURRANTS AND GOOSEBERRIES 1711

commonly regarded as healthy preparations. The

fruits are also used for jams and jellies, and are

suitable for flavoring other foods, such as yogurt,

icecream, and other diary products, and in bakery

products such as pies.

0023 Red currants are mainly grown for juice and jelly

processing, often mixed with other fruits with lower

acidity, and are used as a component in mixed juice,

where they add a stronger character to the product.

0024 Gooseberry is mainly used for jam and canned

products and, to some extent, for juice production.

All three fruits are used for berry wine production,

alone or in combinations with other raw materials.

Blackcurrants are also used for sweet liqueurs, such as

‘Cre

me de cassis’ in France.

0025 Blackcurrant is rich in polyphenolic color prod-

ucts, and the g-linolenic fatty acid produced from

blackcurrant seeds is used as a health preparation.

Manufacture of the oil is based on press cake from

blackcurrant juice processing. In blackcurrant, other

parts of the plants are also of commercial interest.

The leaves may be used for tea, and bud extracts have

been used as a flavor component in other foods and as

an ingredient in some fragrances.

See also: Ascorbic Acid: Properties and Determination;

Colorants (Colourants): Properties and Determination of

Natural Pigments; Tannins and Polyphenols

Further Reading

Agar T, Streif J and Bangerth F (1991) Changes in some

quality characteristics of red and blackcurrants stored

under CA and high CO

conditions. Gartenbauwis-

senschaft 56(4): 141–148.

Batzer U and Helm HU (1999) Lagerung von Beerenobst.

Erwerbsobstbau 41: 51–55.

Brennan R (1996) Currants and gooseberries. In: Janick J

and Moore JN (eds) Fruit Breeding Vine and Small Fruit,

vol. 2, pp. 191–297. New York: John Wiley.

Dietrich H, Kru

ger E, Patz C-D and Scho

pplein E (2000)

Characterisierung von Schwartzen Johannisbeersorten

im Hinblick auf die Saft- und Nektarherstellung. Obst-,

Gemu

se- und Kartoffelverarbeitung 85(2): 86–98.

Green A (1971) Soft fruits. In: Hulme AC (ed.) Biochemis-

try of Fruits and their Products, vol. 2, pp. 375–410.

London: Academic Press.

Heiberg N (1986) Quality components of blackcurrant

(Ribes nigrum L.) fruits as related to degree of ripeness

and cultivar. Meldinger fra Norges landbrukshøgskole

65(24): 25

Heiberg N and Ma

ge F (1991) Evaluation of ten black-

currant cultivars. Norwegian Journal of Agricultural

Sciences 5: 277–282.

Heiberg N, Ma

ge F and Haffner K (1992) Chemical com-

position of ten blackcurrant (Ribes nigrum L.) cultivars.

Acta Agriculturae Scandinavica, Section B, Soil and

Plant Science 42: 251–254.

Herrmann K (1997a) Inhaltsstoffe der Johannisbeeren. Die

industrielle Obst- und Gemu

severwertung 82(1): 14–20.

Herrmann K (1997b) Inhaltsstoffe der Stachelbeeren. Die

industrielle Obst- und Gemu

severwertung 82(2): 34–36.

Kuusi T (1970) Uber die chemische Zusammensetzung und

Kennzahlen einiger finnischer einheimischer Beeren.

Flu

ssiges Obst 37: 188–190, 253–263.

ge F (1993) Vegetative, generative and quality charac-

teristics of four blackcurrant (Ribes nigrum L.) cultivars.

Norwegian Journal of Agricultural Sciences 7: 327–332.

CYCLAMATES

J F Lawrence, Sir F.G. Banting Research Centre,

Ottawa, Ontario, Canada

Introduction

0001 ‘Cyclamate’ is the term given to the artificial sweet-

ener cyclamic acid (cyclohexylsulfamic acid) and its

calcium or sodium salts (see Figure 1). Cyclamate was

discovered in 1937 at the University of Illinois,

following the accidental contamination of a cigarette

with a derivative of cyclohexylamine. In 1940,

DuPont obtained a patent for its production, and in

1950, it was available to consumers. Consumption of

cyclamates increased steadily from that time up to

about 1969, when it was banned in the USA and

other countries due to safety concerns related to its

potential carcinogenicity. However, recent studies

have contradicted the earlier work, and cyclamate

continues to be used in many countries (see section

on ‘Metabolism and Safety’). Cyclamate is not

metabolized by the human body, so it contributes no

energy to the diet and is considered a nonnutritive

sweetener.

NH SO

−

fig0001Figure 1 Structure of cyclamate (sodium salt).

1712 CYCLAMATES

Sweetness

0002 In comparison with other intense sweeteners, cycla-

mate is perhaps the least sweet, being only 30–80 times

as sweet as sucrose in actual food uses, depending upon

concentration, pH, flavoring agents and other ingredi-

ents that may constitute a part of the food product.

Aspartame, by comparison, is about 200 times sweeter

than sucrose, whereas saccharin is about 300 times

sweeter. In high concentrations, cyclamate has an un-

pleasant aftertaste. However, at low concentrations, it

has some bitterness-masking ability that makes it at-

tractive for use in pharmaceutical products. During the

1960s, cyclamate–saccharin combinations became

very popular. At ratios of 10:1 (cyclamate:saccharin)

on a weight basis, the combination resulted in a pleas-

ant sweetness, minimizing the somewhat disagreeable

aftertastes of both sweeteners individually. The syner-

gistic effect of saccharin in combination with cycla-

mate increased the sweetening power of the mixture

compared with the individual sweeteners.

Production, Physical, and Chemical

Properties

0003 Cyclamate and its calcium or sodium salts are white

crystalline powders with intensely sweet tastes. Cyc-

lamate has a melting point of about 169–170



C. It is

soluble in water up to a concentration of about 1 g in

7.5 ml, whereas the calcium and sodium salts are

slightly more soluble, to the extent of about 1 g in

4 ml of water. Cyclamate is rather acidic (the pH

of a 10% aqueous solution being 0.8–1.6), whereas

similar solutions of the calcium and sodium salts are

neutral (pH 5.5–7.5). Cyclamate is relatively heat-

stable, microbiologically inert, and nonhygroscopic.

0004Cyclamate is synthesized by sulfonation of cyclo-

hexylamine with chlorosulfonic acid in chloroform

followed by treatment with barium hydroxide and

sulfuric acid. Variations of this reaction scheme

followed by treatment with sodium or calcium

hydroxides yield the salts of cyclamate. Commercial

production of cyclamate reached a peak in the USA

in 1968, when an estimated 7400 tonnes were

tbl0001Table 1 Cyclamate use levels in diet food products

Diet food Cyclamatelevel

Table top sweeteners 25 mg g

1

Milk beverages 0.8 mg ml

1

Beverages and beverage bases 4 mg ml

1

prepared drink

Gelatin, puddings, filling 27 mg ml

1

Salad dressings 1.6 mg ml

1

Jellies, jams, preserves 30 mg ml

1

Sweet sauces, toppings, syrups 30 mg ml

1

Chewing gum 20 mg per stick

Hard confectionery 5 mg g

1

Baked goods, baking mixes 2.6 mg g

1

NHSO

All species

Monkey

Rabbit

Human

Aminocyclohexanols

H NHOH

N-Hydroxycyclohexylamine trans-Cyclohexan-1,2-diol

Cyclohexanol

Human

Dog

Rabbit

Guinea-pig

Monkey

Rat

Monkey

Guinea-pig

Rabbit

Rat

Human

Rat

Rabbit

Guinea-pig

Cyclamate Cyclohexylamine

Cyclohexanone

fig0002 Figure 2 Schematic of the metabolic routes for cyclamate in several mammalian species.

CYCLAMATES 1713

produced. Commercial production dropped dramat-

ically after bans on its use in foods came into effect in

many countries around 1970.

Food Uses

0005 Cyclamate is not permitted as a food additive in a

number of developed countries, including Canada

and the USA. Prior to 1970, cyclamate was used in a

variety of diet food products. In 1969, 70% of the

usage of cyclamate was in beverages, whereas 15%

was in dietetic foods and 15% in table top products.

Table 1 lists some of its past applications and

approximate concentration levels. Like saccharin,

cyclamate is rather stable to heat and moisture, and

thus it was suited to sweetening a wide variety of food

products. It found wide use as a sweetener in combin-

ation with saccharin, as mentioned above.

Metabolism and Safety

0006 Figure 2 shows a schematic of the overall metabolism

of cyclamate in a number of mammalian species. In

humans, orally administered cyclamate is rapidly

excreted via both the urine and feces. More than

98% of the dose is excreted within 1–2 days. Studies

with rats and dogs have shown that small amounts of

cyclamate can be distributed to all tissues (except the

brain), although accumulation is negligible.

0007 Conversion of cyclamate to cyclohexylamine in

human subjects was first reported by Japanese

researchers in 1966. Very small amounts of cyclo-

hexylamine (0.7% of the administered dose) were

found in the urine. This finding stimulated a large

number of feeding studies in humans and animals. It

appears that Enterococci organisms in the intestine

convert cyclamate to cyclohexylamine. Cyclohexyla-

mine may be converted to other metabolites as shown

in Figure 2. The metabolism of cyclamate to cyclohex-

ylamine and other products is dependent on the indi-

vidual concerned. In one study involving 1000 human

subjects, 10–30% of the subjects converted ingested

cyclamate to cyclohexylamine mostly in the range of

< 0.1–8% of the administered dose. However, some

individuals converted up to 60% of the cyclamate.

0008 Cyclamate was banned from use in many countries

because the results of some rat-feeding studies showed

the substance to cause bladder tumors. Many scien-

tists questioned the results of the original studies, and

this led to many follow-up studies in a variety of

animal species. Of note are the results of a 22-year

feeding study in monkeys carried out by the National

Institutes of Health in the USA that showed that

neither cyclamate (nor saccharin) demonstrated

any evidence of carcinogenic effects. The prevailing

opinion today is that neither cyclamate nor cyclo-

hexylamine is likely to be carcinogenic to humans,

especially at the levels recommended for diet foods

(see Table 1). The main reason now that cyclamate is

not permitted is that during the follow-up feeding

studies to evaluate its carcinogenicity, it was observed

that cyclohexylamine, the main metabolite of cycla-

mate, caused irreversible testicular atrophy in rats.

Further research is required to study this effect in

detail. The Food and Agriculture Organization/

World Health Organization has determined an ac-

ceptable daily intake (ADI) value (the maximum

amount that could be consumed daily for a lifetime

without appreciable risk) for cyclamate to be 11 mg

per kilogram of body weight. However, in the UK, a

temporary maximum ADI of only 1.5 mg per kilo-

gram of body weight has been established until the

results of further research are known.

Analysis

0009Methods for the determination of cyclamate in foods

are not as simple or as straightforward as for those

sweeteners such as acesulfam-K, aspartame, and

saccharin, which strongly absorb ultraviolet light.

The latter can be measured by direct means (usually

high-performance liquid chromatography) without

recourse to chemical derivatization.

0010The most common analytical methods for cycla-

mate involve chemical conversion to cyclohexylamine

followed by determination of the amine by gas chro-

matography with flame ionization detection. Several

methods employing high-performance liquid chroma-

tography have been evaluated, which offer potential

for cyclamate determination without the need to

convert to cyclohexylamine or other product. These

employ direct conductivity detection, indirect ultra-

violet absorption detection, or postcolumn ion-pair

extraction detection.