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

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and 60 kg. Individual fruits (fingers) can number up

to 300 on a bunch. Fingers of different varieties can

be anywhere from 6 to 60 cm in length and from 50 to

1000 g in weight, but are more usually 15–30 cm long

and weigh 50–200 g. The curved shape of the fruit is

caused by a negative geotropic growth response. Im-

mature bananas are usually green, and when mature

they ripen to a yellow color. Young fruits are some-

what angular, but this disappears with maturity in the

AAA varieties. AAB and ABB varieties may still be

angular at maturity.

0014The fruit is a berry that develops from the inferior

ovary of the female flower. It is parthenocarpic, i.e.,

it develops without the stimulus of pollination. The

ovules shrivel early but can still be recognized as

brown specks in the center of mature fruit. Most

varieties are sterile or have very low fertility. If a

pollen source, such as a wild species, is nearby, some

varieties will set an occasional dark hard seed about

3–5 mm in diameter. These are a hazard to the teeth

of consumers so it is fortunate that seeds are an

extremely rare event.

0015In the growing fruit, the pulp-to-peel ratio of fresh

weight varies from about 1:1 to 4:1, depending upon

variety and maturity at harvest. When the mature

fruit ripens, the pulp-to-peel ratio increases, and this

is thought to be in part as a result of water movement

from the peel to the pulp associated with the hydroly-

sis of starch to osmotically active sugars.

Nutritional Composition

0016Ripe dessert bananas are considered by many to be a

complete food if taken in association with a protein

source such as milk. They are favored as food for

young babies and elderly people because they are

easily digested and are very nutritious. They are ex-

cellent for people with stomach complaints, particu-

larly ulcers, and are ideal for diets with low levels of

cholesterol, fats, and sodium. The potassium concen-

tration is about 350 mg per 100 g of fresh pulp with

trace amounts of sodium (Table 5). Bananas are also

recommended in the treatment of infant diarrhea,

celiac disease, and colitis. They are a good source of

vitamins C and B

(Tables 5 and 6). A major feature is

the high sugar-to-acid ratio (ranging from 100 to 180)

compared with 7–10 for citrus. This is confirmed by

the carbohydrate concentrations shown in Tables 5

and 7. If we assume 20% of the fresh banana pulp is

sugar and 76% water, then 83% of the dried solids

are sugar (Tables 5 and 7). This is why bananas have

recently received much attention from people in sport

because of the high carbohydrate content, capable

of rapidly releasing energy necessary for vigorous

sporting events. The sugars are almost entirely glu-

cose, fructose, and sucrose, in a ratio of 20:15:65.

The high sugar concentration of ripe bananas is

exceeded in fresh fruit only by that of dates, jujube,

tamarind, and carob. (See Celiac (Coeliac) Disease;

Colon: Diseases and Disorders; Exercise: Metabolic

fig0002 Figure 2 (see color plate 1) A wide range of banana varieties

are available in South-east Asian markets. Reproduced from

Bananas and Plantains. Encyclopaedia of Food Science, Food Tech-

nology and Nutrition, Macrae R, Robinson RK and Sadler MJ

(eds), 1993, Academic Press.

Sucker

Pseudostem

Male

bud

Finger

Hand

Bunch

fig0003 Figure 3 Banana plant, bunch, and fruit morphology. Repro-

duced from Bananas and Plantains. Encyclopaedia of Food Sci-

ence, Food Technology and Nutrition, Macrae R, Robinson RK and

Sadler MJ (eds), 1993, Academic Press.

BANANAS AND PLANTAINS 375

Requirements; Infants: Nutritional Requirements.)

See also individual nutrients.

0017 The characteristic aroma of bananas has received

considerable attention, with more than 350 volatile

compounds having been identified. The major con-

stituents appear to be amyl and isoamyl esters of

acetic, propionic, and butyric acids.

0018 The major differences between bananas and plan-

tains are: (1) the lower moisture percentage of the

pulp in green plantains compared with ripe bananas

(Tables 5 and 7); (2) the lower sugar concentration in

ripe plantains compared with ripe bananas; and (3)

plantains are a much richer source of vitamin A than

bananas (Tables 5 and 6). These differences are valid

for the edible product, but are less important if fruits

are compared at the same stage of ripeness. For

example, the moisture percentage can increase from

about 60% in preclimacteric banana fruit to 70%

after ripening and 75–80% at the stage of senescence.

In addition, there are major inconsistencies in the

literature regarding the conversion of starch to sugar

in plantains, with some references indicating only

traces of starch in the ripe fruit. Some of the differ-

ences are probably due to different ripening condi-

tions and the stage of ripeness selected for

measurement. (See Ripening of Fruit.)

Fresh Fruit Handling and Storage

0019Handling procedures vary substantially in the differ-

ent banana-producing countries and depend upon

whether fruit is to be exported. This discussion is

based largely on procedures adopted in commercial

plantings producing fruit for export because it

provides an understanding of the factors involved.

0020Bananas travel best and receive a minimum of

mechanical damage while they are in a hard, green

condition. It is necessary to transport the fruits to the

marketplace in this hard, green state so that they can

be uniformly ripened with ethylene gas (1000 mg l

1

)

in humidified rooms at 15–18



C. This greatly facili-

tates marketing. Fruits can take from a few days to

3 weeks to reach the marketplace, and so must have

sufficient greenlife (the period after harvest for which

the fruit stays in a hard green condition) to survive

this journey. No postharvest treatment can improve

upon the inherent greenlife, but treatments can

reduce its rate of decline. In general, the earlier the

harvest in the life of the fruit, the greater is the fruit

greenlife, but any gain in greenlife must be balanced

against the loss in bunch weight (5–10% per week).

A bunch that would ripen in the field 5 months after it

emerged may be harvested and ripened satisfactorily

as early as about 10 weeks (pulp-to-peel ratio of 1:1),

when the fingers are still quite thin. A key to profit-

able banana growing is to maximize yield without

premature ripening occurring. Other considerations

tbl0005 Table 5 Compositional data per 100 g edible portion of plantains (unripe) and bananas (ripe)

Proximate analysis (g) Mineral content (mg) Vitamin content

Components Plantain Banana Minerals Plantain Banana Vitamins Plantain Banana

Water 67.5 75.1 Sodium 4 1 Retinol (mg) 0 0

Sugars 5.7 20.9 Potassium 500 400 Carotene (mg) 360 21

Starch 23.7 2.3 Calcium 9 6 Vitamin D (mg) 0 0

Dietary fiber 2.3 3.1 Magnesium 37 34 Thiamin (mg) 0.10 0.04

Total nitrogen 0.18 0.19 Phosphorus 36 28 Riboflavin (mg) 0.05 0.06

Protein 1.1 1.2 Iron 0.5 0.3 Nicotinic acid (mg) 0.7 0.7

Fat 0.3 0.3 Copper 0.08 0.1 Ascorbic acid (mg) 15.0 11

Zinc 0.1 0.2 Vitamin E (mg) 0.20 0.27

Chlorine 80 79 Vitamin B

(mg) 0.30 0.29

Vitamin B

(mg) 0 0

Folate (mg) 22 14

Pantothenate (mg) 0.26 0.36

Source: Holland B, Welch AA, Unwin ID, Buss DH, Paul AA and Southgate DAT (1991) McCance and Widdowson’s The Composition of Foods, Fifth revised

and extended edition. London: The Royal Society of Chemistry and Ministry of Agriculture, Fisheries and Food.

tbl0006 Table 6 Nutrient content of the fruit pulp of banana varieties

Percentage of US RDA

per 100 g

Nutrient Gros Michel

Cavendish

Horn Plantain

Vitamin A 3.8 5.1 61.6

Ascorbic acid 13.3 20.0 26.7

Vitamin B

25.0

Thiamin 3.3 2.6 2.9

Riboflavin 3.8 5.3 5.9

Nicotinic acid 4.7 4.8 4.0

US recommended dietary allowance.

Source: USDA (1963) Composition of Foods. Agriculture Handbook 8.

Washington, DC: US Government Printing Office.

Source: Anonymous (1959) Bananas: Versatile in Health or Illness. Boston:

United Fruit.

NA, not available.

376 BANANAS AND PLANTAINS

are that greater fruit maturity leads to a higher pro-

portion of edible pulp and possibly an increase in fruit

flavor. In practice, maturity standards are varied, so

that more mature bunches are harvested for nearer

markets and less mature ones for more distant

markets.

0021 Maximum greenlife for a particular finger diameter

(grade) at harvest is achieved by manipulating the

plant and environment to obtain the maximum pos-

sible rate of fruit filling. Finger diameter, bunch age,

and degree of fruit fullness (loss of angularity) are

used as criteria for harvest. The combination of age-

grade control for determining time of harvest insures

the production of high-quality fruit with sufficient

greenlife at harvest. To minimize the risk of prema-

ture ripening after harvest, it is important to keep the

fruit as cool as possible (but above 13



C to prevent

chilling injury) and not to expose it unnecessarily to

light.

0022 Banana bunches are harvested by hand and usu-

ally carried on the shoulder to nearby cableways

(Figure 4) or tractor-drawn, padded trailers. The

plastic sleeve, known as a bunch cover, that is applied

to the young bunch to improve fruit quality is retained

to minimize mechanical damage during handling. In

the packing shed, the bunch cover is removed, the

bunches are dehanded, usually into tanks of water,

and then fruit is sorted, graded, divided into clusters

of 4–10 fingers, weighed, labeled, and packed into

fiberboard cartons containing plastic liners. Fungicide

may be applied in a separate operation before the

fruit is packed. Cartons hold from 12 to 18 kg

of fruit. The packed fruit is sent by refrigerated trans-

port to the marketplace and usually involves transport

by rail, road, and sea. The transport system is highly

integrated and regular (at least weekly) so that fruit of

uniform maturity is marketed. This has the effect of

avoiding the need for storage beyond the shipment

period. (See Fungicides.)

0023Bananas are usually consumed within 3–4 weeks

from the day of harvest, with no long-term commer-

cial storage possible, as for citrus and pome fruits. It is

possible to delay the onset of ripening by a few weeks

by the use of modified atmosphere storage with high

carbon dioxide (5%) and low oxygen (2%) and with

ethylene scrubbers, such as potassium permanganate,

but because banana fruit is available year round there

is usually no advantage in doing this. However, in

places where the expensive technology of refrigeration

is not available, this technique may be valuable for

marketing fruit in distant markets.

0024Once the fruit ripens, the period over which it may

be eaten, its shelf-life, is relatively short. It is usually

of the order of 2–10 days depending upon variety and

ambient temperature. The extremely perishable

nature of banana is associated with its high rate of

metabolism – the rate of respiration during the cli-

macteric is 100–180 ml of oxygen per kg of fruit per h

and 40–60 ml kg

1

whilst green. This is higher

than apples and pears, which have a respiration rate

of 6–40 ml of oxygen per hour at similar tempera-

tures. Lower temperatures will reduce the metabolic

rate. A reduction of 10



C usually halves the rate.

Chilling injury occurs when the fruit is kept for a

long period below 13



fig0004 Figure 4 (see color plate 2) Bananas for export are usually

transported to the packing shed by cableways to minimize skin

blemishes due to mechanical damage. Reproduced from

Bananas and Plantains. Encyclopaedia of Food Science, Food Tech-

nology and Nutrition, Macrae R, Robinson RK and Sadler MJ

(eds), 1993, Academic Press.

tbl0007 Table 7 Proximate analysis (g per 100 g) of banana and plantain

Banana Plantain

Edible portion Oven-dried solids Edible portion Oven-dried solids

Water 75.7 66.4

Carbohydrate 22.2 91.4 31.2 92.8

Protein 1.1 4.5 1.1 3.3

Fat 0.2 0.8 0.4 1.2

Ash 0.8 3.3 0.9 2.7

Source: USDA (1963) Composition of Foods. Agriculture Handbook 8. Washington, DC: US Government Printing Office.

BANANAS AND PLANTAINS 377

Fruit Utilization

0025 Almost half of the bananas and plantains produced

are eaten raw as a dessert fruit; the other half is

cooked, usually by frying, boiling, roasting, or

baking. Virtually all varieties of bananas and plan-

tains may be either eaten raw when ripe, or cooked

when either green or ripe. Cultural preferences

govern the choices made.

0026 Bananas can be processed in various ways so that

they may be stored and utilized for other purposes.

Fruits that are unmarketable because of small size or

some peel blemishes are suitable for processing.

0027 Banana pure

e is the most important processed

product made from the pulp of ripe fruit. The pure

is canned and used as an ingredient in dairy desserts,

bakery items, drinks, processed foods, and sauces,

and as a part of special diets in hospitals and nursing

homes. Ripe bananas are also sliced and canned in an

acidified syrup and are used in desserts, fruit salads,

cocktail drinks, and bakery items.

0028 Chips are made by deep-frying thin slices of unripe

fruit, with the optional addition of various flavorings,

and sold as a snackfood like potato crisps. Ripe

banana may be dried (known as banana figs in

some regions) and is said to store satisfactorily for

over 10 years without the addition of preservatives.

This would presumably be due to the high sugar

content, which is in excess of 50%. The ripe fruit is

ideal for ice-blocks (water ices, ice lollies), when

peeled and frozen, with the optional addition of top-

pings such as chocolate and chopped nuts. It is an

excellent base for icecreams because of its creamy

consistency.

0029 The other major processed products are flour made

from dried unripe fruit, and essence which is ex-

tracted from the pulp of ripe fruit. When ripe fruit is

fermented it makes a low-alcohol beer. Beer manufac-

ture is confined to East Africa, with consumption

being as much as 1.2 l per person per day in Rwanda.

Less important processed products include a clarified

juice, powder, jams, flakes, freeze-dried slices,

ketchup ‘filler’, vinegar, and wine. Unripe bananas

have been used to make starch, but none is currently

produced.

0030 Green banana fruit, pseudostems, and foliage are

suitable as animal feed. They provide a source of

energy and require supplementation with a protein

source. Bananas are only economical as a source of

animal feed when the livestock are nearby, because

of the high cost of transport. The corms, shoots, and

male buds find widespread use as an animal food in

Asia and Africa.

Conclusion

0031Bananas have become the major fresh fruit consumed

around the world, even in the temperate zone where

they are not grown, despite the fact that they cannot

be stored for more than a few weeks. This has been

possible because they can be produced all year round,

are competitively priced, come packed in an hygienic,

easily opened peel, are extremely convenient to eat in

virtually all situations and, as William Forsyth put it,

‘The suave melting texture of a fully ripe banana

combined with its distinctive mellow flavour makes

a delicious combination.’

See also: Celiac (Coeliac) Disease; Colon: Diseases and

Disorders; Exercise: Metabolic Requirements; Fruits of

Tropical Climates: Commercial and Dietary Importance;

Fungicides; Infants: Nutritional Requirements;

Ripening of Fruit

Further Reading

Champion J (1963) Le Bananier. Paris: Maisonneuve et

Larose.

Forsyth WGC (1980) Banana and plantain. In: Nagy S and

Shaw PE (eds) Tropical and Subtropical Fruit, pp. 258–

278. Westport, Connecticut: AVI.

Gowen S (1995) Bananas and Plantains. London: Chapman

& Hall.

Hassan A and Pantastico EB (eds) (1990) Banana – Fruit

Development, Postharvest Physiology, Handling and

Marketing in ASEAN. Jakarta: ASEAN-COFAF.

Israeli Y and Blumenfeld A (1985) Musa. In: Halevy A (ed)

CRC Handbook of Flowering, pp. 390–409. Boca

Raton, Florida: CRC Press.

Jones DR (ed) (1999) Diseases of Banana, Abaca and Enset.

Wallingford: CAB International.

Marriott J (1980) Bananas – physiology and biochemistry

of storage and ripening for optimum quality. CRC Crit-

ical Reviews in Food Science and Nutrition 13: 41–88.

Soto M (1985) Bananos: Cultivo y Comercializacio

n. Costa

Rica: Litogratia e Imprenta LIL.

Stover RH and Simmonds NW (1987) Bananas, 3rd edn.

London: Longman.

Turner DW (1997) Bananas and plantains. In: Mitra SK

(ed) Postharvest Physiology and Storage of Tropical

and Subtropical Fruits, pp. 47–83. Wallingford: CAB

International.

Von Loesecke HW (1950) Bananas. New York: Inter-

science.

378 BANANAS AND PLANTAINS

BARLEY

A W MacGregor, Canadian Grain Commission,

Winnipeg, Manitoba, Canada

Introduction

0001 Barley is one of the major cereal crops in the world.

This article reviews its origin, botany, distribution,

chemical composition, and uses as food and feed.

Utilization of barley in the malting and fermentation

industries (brewing, distilling, alcohol production) is

covered in other articles.

Botany

0002 Barley is a member of the grass family Gramineae,

the subfamily Festucoideae, the tribe Hordeae and the

genus Hordeum. Cultivated barleys belong to the

subspecies vulgare, whereas the wild forms of barley

belong to the subspecies spontaneum. The basic

chromosome number of the genus Hordeum is 7,

and all cultivated barleys are self-fertilizing, diploid

annuals (2n ¼ 14).

0003 The spike or head of barley consists of a series of

spikelets that are attached – in sets of three – at nodes

to alternating sides of the rachis. Each spikelet con-

tains a floret. In six-rowed barley (Figure 1a), each

floret is fertile and develops into a kernel, leading to

the formation of six rows of kernels. Only the central

kernel in each triplet is symmetrical; the lateral

kernels are twisted to varying degrees. Therefore,

two-thirds of the kernels in a sample of six-rowed

barley will be nonsymmetrical. In two-rowed barley,

the lateral florets are not fertile, so that only the

central floret in each triplet develops into a kernel

(Figure 1b), leading to the formation of two rows of

symmetrical kernels in the mature spike. All culti-

vated barleys are either two- or six-rowed, but some

six-rowed cultivars appear to have only four rows of

kernels; thus, reference is sometimes made to four-

rowed barleys, although these are really six-rowed

barleys.

0004 The barley kernel consists of many different tissues;

some of these are shown in Figure 2. Outer layers of

the kernel and the area between the embryo and the

starchy endosperm are shown in detail in Figure 2a

and b. In botanical terms, the barley seed is that part

of the kernel enclosed by the testa. Hence, the testa is

often referred to as the seed coat. Surrounding the

testa and fused tightly to it is the pericarp, the outer

tissue of the grain or caryopsis. Since a caryopsis is a

fruit, barley is a fruit containing a seed. The hull or

husk completely surrounds the grain and adheres

tightly to the pericarp in most barley cultivars. In

some cultivars, however, the so-called naked or hull-

less types, the hull is loosely attached to the grain and

is removed during threshing. (See Wheat: Grain

Structure of Wheat and Wheat-based Products.)

Origin, Adaptation, and Production

0005Neither the place of origin nor the progenitor of

cultivated barley is known with certainty. There

is archeological evidence that from about 7000 bc

barley was cultivated in the fertile crescent of the

Middle East. This area includes present-day Israel,

Jordan, Syria, and Iran. There is evidence also that

barley may have been cultivated even earlier than that

in the Nile Valley of Egypt, but considerably later in

India and China. It is probable, but by no means

certain, that two-rowed Hordeum spontaneum is

the ancestor of cultivated barley, but this subspecies

Spike

Spikelets

(a) (b)

fig0001Figure 1 Barley spikes and spikelets. (a) Six-rowed barley.

(b) Two-rowed barley. Reproduced from Barley, Encyclopaedia

of Food Science, Food Technology and Nutrition, Macrae R, Robin-

son RK and Sadler MJ (eds), 1993, Academic Press.

BARLEY 379

may be an intermediate between the actual barley

progenitor and cultivated barley. Six-rowed forms of

barley are thought to have developed from early two-

rowed forms through mutation and hybridization.

0006 Barley is a widely adapted crop and grows under a

wider range of environmental conditions than any

other cereal. It appears to require fewer heat units

than other cereals to reach physiological maturity and

can therefore be grown successfully at higher lati-

tudes and altitudes than other cereal crops. Barley is

relatively tolerant to drought and to alkaline and salt

conditions but grows best in temperate regions of the

world where growing seasons are long, cool, and

moderately dry.

0007 Winter barley is less cold-tolerant than either

winter wheat or winter rye. Nevertheless, in some

countries with temperate climates, such as the UK,

most of the barley is grown during winter. In coun-

tries such as Australia and Spain, which experience

hot summers, a significant proportion of the barley

is grown during the winter. Conversely, the harsh

winters of North America preclude the growing of

winter barley, except for some areas in the southern

USA.

0008 Over the past 10 years, world-wide production of

barley has averaged 51.0 10

t(Table 1). This

places barley fourth after wheat, maize, and rice in

terms of total annual production. In 2000, barley

accounted for 8.4% of the world’s total cereal pro-

duction. The former USSR is the largest producer of

barley, but it is all consumed internally. Canada, the

USA, and Australia each produce much smaller quan-

tities but they, as well as members of the EU, are

major barley exporters. (See Cereals: Contribution

to the Diet.)

Composition

0009The major constituent of barley kernels is starch,

which is present in the endosperm in the form of

discrete granules (Figure 2) and represents, on aver-

age, 60–64% of the weight of the kernel (Table 2).

Starch consists of two high-molecular-weight poly-

mers of glucose: amylose and amylopectin. Amylose

is composed of long chains of glucose residues linked

by a-(1,!4) bonds with a few side-chains joined to

the main chains through a-(1,!6) bonds. Amylopec-

tin contains much shorter unit chains of a(1,!4)-

linked glucose residues that are inter-linked through

a-(1,!6) bonds. In other words, amylose is lightly

branched, and amylopectin is heavily branched. In

general, barley starch contains about 75% amylopec-

tin and 25% amylose. However, starch from ‘waxy’

barley cultivars contains 95–100% amylopectin, and

starch from high-amylose barley cultivars may con-

tain more than 40% amylose. These starches have

different functional properties, but they have not yet

been utilized widely in the food industry.

0010The major component of endosperm cell walls is the

polysaccharide, (1,!3), (1,!4)-b-d-glucan, which

Endosperm Testa

Husk

(a)

Aleurone Pericarp

Endosperm

Depleted layer

(b)

Embryo

Scutellum Endosperm

fig0002 Figure 2 Diagram of a longitudinal section of a barley kernel.

(a) Outer layers of kernel. (b) Junction between the embryo and

endosperm. Reproduced from Barley, Encyclopaedia of Food Sci-

ence, Food Technology and Nutrition, Macrae R, Robinson RK and

Sadler MJ (eds), 1993, Academic Press.

tbl0001Table 1 World production of barley

Country Average production (1991^2000)

(thousandmetric tonnes)

Former USSR 39 935

Canada 12 870

Germany 12 397

France 9 551

Spain 8 537

USA 8 131

Turkey 7 150

UK 6 918

Australia 5 568

China 3 867

Denmark 3 859

Kazakstan 3 681

Poland 3 344

Other 25 551

Total 151 349

From Canadian Grains Council Statistical Handbook (2001). Winnipeg:

Canada Grains Council.

380 BARLEY

forms highly viscous, aqueous solutions. These high

viscosities may cause filtration problems during

brewing and digestive problems when untreated

barley is fed to chickens. Conversely, there

is substantial evidence that ingestion of b-glucan

can lead to lowered levels of serum cholesterol and

of glucose and insulin responses. These are all

beneficial responses. Arabinoxylans, which are poly-

mers of xylose and arabinose, are present, in both

soluble and insoluble forms, mainly in the cell

walls of endosperm and aleurone tissues. They absorb

many times their own weight of water and also

form viscous solutions in water. Small amounts of

cellulose are present in the outer tissues of barley

kernels.

0011 Only small amounts of the simple sugars, glucose

and fructose, are present in the kernel; the major

sugars are sucrose and raffinose, which are present

mainly in the embryo. Varying amounts of fructosans,

which are fructosyl polymers of sucrose, are also

present in the mature kernel.

0012 Barley contains a large number of proteins, which

can be separated into four major groups on the basis

of solubility. Albumins and globulins (15–30% of

barley protein) are soluble in water and salt solutions,

respectively; hordeins (35–50% of barley protein),

the major storage proteins in barley, are soluble in

aqueous alcohol solutions; glutelins (15–20% of

barley protein), a mixture of storage and structural

proteins, are soluble in alkali. Although aleurone cells

are rich in protein, mainly globulins, most of the

barley protein is in the endosperm, especially in

the subaleurone region.

0013 About 70% of barley lipid is present in the endo-

sperm, 20% is in the embryo, and the remainder is in

the outer layers of the kernel.

0014 Minerals such as magnesium, sulfur, sodium, po-

tassium, zinc, and calcium are concentrated in the

outer layers of the kernel. Phosphorus is present,

mainly, as phytic acid in the aleurone. Refer to Indi-

vidual nutrients (See Cereals: Dietary Importance.)

Uses

Animal Feed

0015The largest use of barley, world-wide, is as animal

feed, especially for cattle and pigs. Barley provides a

good balance of high energy, because of its starch

content, and reasonable protein quality and content.

Hulled barley is less desirable than other cereal

grains, such as maize, for chicken feed formulations

because of its relatively high fiber content. There is

increasing interest in developing hull-less barleys for

feeding to pigs.

Malting, Brewing, and Distilling

0016The proportion of the total barley production used

for malting varies widely among countries, but

world-wide utilization is about 15% of total produc-

tion. This aspect of barley utilization is discussed

more fully in another entry. (See Beers: Wort Produc-

tion; Malt: Malt Types and Products; Chemistry of

Malting.)

Human Food

0017Less than 5% of total barley production is used for

human food in most developed countries, but in some

countries in the Far East, Middle East, and North

Africa, barley products form an important part of

the diet. The most common products are blocked,

pot and pearl barley, barley flakes, and barley flour.

Blocked barley is prepared by lightly scarifying the

grain between abrasive disks to remove the husk.

More severe treatment (pearling) results in removal

of the outer kernel layers and rounding of the grain to

produce pot barley, which amounts to about 65% of

the starting material. Extensive pearling leads to re-

moval of the outer endosperm layers and the embryo

to leave pearled barley, which is only about 35% of

the original barley. These products are used in soups,

breakfast cereals, and stews, as tea or coffee substi-

tutes after roasting, and as rice extenders. They can

also be milled into flour and used in baby foods,

porridge, and some baked goods when blended with

wheat flour. Barley may be puffed by heating it under

pressure to gelatinize the starch and then releasing the

pressure suddenly. The loss in pressure allows rapid

expansion of the water vapor and significant puffing

of the grain. Barley flakes are made by cooking the

barley, rolling the hot, moist product between heavy

rollers, and drying the flakes to about 10.5% mois-

ture content. (See Cereals: Breakfast Cereal.)

tbl0002 Table 2 Barley composition

Component Content (%, dry weight)

Starch 60–64

Arabinoxylans 4.4–7.8

b-Glucans 3.6–6.1

Cellulose 1.4–5.0

Simple carbohydrates (glucose,

fructose, sucrose, maltose)

0.41–2.9

Oligosaccharides (raffinose,

fructosans)

0.16–1.8

Proteins 8–15

Lipids 2–3

Minerals 2–3

Barley also contains small quantities of the B-complex vitamins, including

thiamin (B

), riboflavin (B

), nicotinic acid, pyridoxine (B

) and pantothenic

acid, biotin, folic acid, and vitamin E.

BARLEY 381

0018 Nutrients are not distributed uniformly throughout

the barley kernel. Vitamins, minerals and lipids are

concentrated in the outer layers and embryo of the

grain, and peripheral regions of the endosperm have

significantly more protein than central regions.

During pearling, therefore, the nutritive value of the

product decreases as the outer layers of the kernel are

removed. Pearl barley, for example, is nutritionally

inferior to pot barley because it does not contain the

embryo or any of the nutritionally rich outer layers of

the kernel. Hull-less barley may offer some advan-

tages over hulled barley in the food industry.

0019 Sound, bright, uniformly plump kernels with a high

test weight (> 60 kg hl

1

) are preferred for all barley

uses. In general, barley cultivars possessing yellow

aleurones are also preferred. There is a small, decreas-

ing demand for malts prepared from blue-aleurone

barley.

Storage

0020 The end-use quality of grain stored under high mois-

ture conditions deteriorates through loss of viability

and attack by insects and microorganisms. The

temperature recommended for safe storage depends

on the moisture content of the grain. Dry grain (12–

13% moisture) can be stored safely at 17



C, but

grain at higher moisture contents deteriorates and

should be dried with cool, dry air before storage.

Barley intended for malting should not be dried

at temperatures over 45



C because the germination

potential of the grain may be damaged. For food and

feed uses, however, temperatures up to 60



C may be

used without impairing quality of the grain. Ideally,

barley should be stored at about 12% moisture and at



C or less. Grain may be treated with insecticides

and pesticides, but some of these may leave unaccept-

able residues on the grain. It is possible to store grain

under anaerobic or low oxygen conditions (e.g.,

under carbon dioxide or nitrogen), thus slowing

down or inhibiting the development of microorgan-

isms and insects. Such treatment does not impair

the germination potential of the grain, nor does it

leave residues on the grain. (See Cereals: Handling

of Grain for Storage; Bulk Storage of Grain.)

See also: Beers: Wort Production; Cereals: Contribution to

the Diet; Bulk Storage of Grain; Handling of Grain for

Storage; Breakfast Cereals; Dietary Importance; Malt:

Malt Types and Products; Chemistry of Malting; Protein:

Food Sources; Starch: Structure, Properties, and

Determination; Trace Elements; Vitamins: Overview;

Wheat: Grain Structure of Wheat and Wheat-based

Products