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

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Toxicity

0010 Sago palm is known to be poisonous and sago separ-

ation includes careful processes to remove these

toxins, before they are edible. Intake of sago before

proper processing to remove toxins can cause

vomiting, liver damage, and even death. Recent evi-

dence indicates that the toxins have neurotoxic effects

and now it is considered to be a slow poison.

0011 It is remarkable that many indigenous people in

different parts of the world have quite independently

adopted different processing techniques. Fleshy seeds,

leaves, unprocessed flour from stem pith, and pollen

grains are considered to be toxic to livestock and to

the population who live in proximity to these plants,

and this has created interest in the pharmaceutical

industry. The general symptoms of Cycas toxicity

include diarrhea, headache, dizziness, vomiting, and

mortality. The major toxic principle in sago palm

poisoning is a glycoside named cycasin and other

toxic glycosides include macrozamin, neocycasin,

and an amino acid b-methylamino-l-alanine (BMAA).

The active component of the glycosides is methy-

lazoxyglycoside (MAM), which is formed by the

cleavage of cycasin (glycosides) with the help of an

enzyme, found in microbes in the gut. MAM is

known to be hepatotoxic and carcinogenic. It causes

apoptosis (programmed cell death) in the brain, thus

reflecting a link between cycad ingestion and devel-

opment of neurodegenerative disorders. BMAA is a

nonprotein amino acid and its chemical structure

shows similarities with beta-N-oxalylamino-l-ala-

nine (BOAA), the neurotoxin from Lathyrus sativus.

There are reports of incidence of amyotrophic lateral

sclerosis (ALS) and parkinsonism dementia (PD) after

Cycas ingestion. Cycasin and its aglycone MAM

impair both rodent and human b-cell function,

which may lead to the death of pancreatic islet cells,

a very high prevalence of glucose intolerance, and

diabetes mellitus.

Utilization of Sago Palm

Stem

0012 Stem starch has been widely used as a food source.

Pith and cortical cells contain a large amount of

starch and yield sago grains and hence the plant is

known as the sago palm. It has been estimated that a

mature stem (i.e., beginning to flower) of about 1 m

yields about 2 kg of sago. Cycas starch is a constituent

of poor people’s food and is used in times of food

scarcity.

0013 To separate the sago, the trunk of the plant is split

and its pith-like center is chopped and ground into

powder and the starch is removed. Before sago separ-

ation there is repeated washing, settling, and discard-

ing of the water to eliminate the toxins. Ingestion of

sago before proper washing leads to vomiting and

dizziness. In Japan, the seeds and stems are often

used to prepare wine. In Africa, to prepare bread

from cycads, the central pith of the stem is taken in

animal skin and buried in the ground for about 40–42

days until it is partially fermented. This fermented

stem is ground up with water and is shaped into

bread and baked. Crushed bark and seeds or mega-

sporophyls, when mixed with coconut oil, are used in

South. India as a poultice for sores and wounds. Since

it contains a toxic glycoside, its constant use is said to

cause intestinal disorders and it is considered to be

genotoxic. Fiber obtained from the stems is used to

make cloth and rope.

Leaves

0014The strong and leathery leaves keep their fresh green

color long after being cut off from the plant and hence

they are used as a nursery stock for funeral wreaths

and church festivals under the name palm branches.

The leaves are also used to decorate marriages

and festivals. Leaves are used to make brooms and

baskets, and to thatch huts. Leaf is also a source of

fiber in the manufacture of cloth, ropes, and twines.

Young fleshy leaves are used as vegetables. Consump-

tion of leaves without proper detoxification is harm-

ful and prolonged ingestion of leaves is toxic.

Roots

0015The roots are a source of sago and in Africa it is

believed that burying the roots by a house could

protect from lightning.

Seeds

0016Mature palms produce seeds in the female cones.

A large plant may yield over 1000 seeds. Mature

seeds are large and orange-red in color. The seeds

attract animals, birds, rodents, and fruit-eating

bats, which help seed dispersal. Intake of these

seeds by domestic animals is toxic and leads to

vomiting, dizziness, salivation, paralysis, and even

death, but in wild animals, it is found to be non-

toxic. To separate the sago, mature seeds are split

open and the kernel is collected and sun-dried for

1 or 2 days. After thorough drying, the toxins are

eliminated from the seeds by immersing it in water

for 3–6 h: the water is stirred well and the foamy

water is drained off. This washing process is

repeated at least seven times for the total removal

of toxins. Thereafter it is dried in sunlight and

ground to prepare flour. Sago flour is pure white

SAGO PALM 5037

in color and is similar to that of wheat or rice flour.

Natives prepare bread, steam cakes, several indigen-

ous dishes/sweets, and even wines. Preparations

from the sago palm flour are considered to be an

effective medicine to cure hemorrhoids (piles). It is

also observed that pregnant women demand sago

palm seed flour preparations as part of their preg-

nancy cravings, particularly if they were in the habit

of consuming sago during their childhood days.

Young seeds on boiling yield a decoction which is

often used as a purgative.

Pollen Grains

0017 Pollen grains formed inside the microsporophyls are

considered to have medicinal properties. In India

‘quacks’ claim it as a folk medicine which has several

health benefits, obtained from ‘kailasam’ (the place of

Lord Shiva). It has been reported that pollen is heavily

laden with cycasin and BMAA and is toxic.

Metroxylon Sagu

0018 Metroxylon sagu is a true palm belonging to the order

Arecales, family Palmae, and subfamily Calamoideae.

It is commonly grown in wild swampy areas of Ma-

laysia, Indonesia, and New Guinea. This palm grows

between 10



N and 10



S latitudes and up to an eleva-

tion ranging from 700 to 1000 m. It is also found

growing in dry lands. In certain regions of the

world, this palm is a provider of staple food. Its

tremendous utility favored its distribution from its

place of origin to far-off distant places, including

South-east Asia. It attains a natural height of 15 m.

The stem is straight, stout, and without branches and

has a unique crown of large pinnate leaves. The roots

are unbranched and go straight down to the soil. Sago

palm grows quickly and it dominates in tropical

peat swamp rainforests, where other crop plants do

not thrive. Sago palm is a kind of semiwild species but

not a well-established crop plant. In the wild and in

cultivation, sago palm is mostly propagated vegeta-

tively through its suckers.

0019 Sago palm is tolerant of highly acidic conditions

(low pH) coupled with high concentration of metals

in the soil like aluminum, iron, and manganese,

which inhibit the growth of other plant species. It

has the ability to grow abundantly in heavy clay

soils, which inhibits the growth of other plant species.

In wild conditions, a cluster of sago palms can be

seen. Each sago cluster consists of several mature

plants and suckers. People used to harvest the mature

trunk, leaving the immature ones and suckers. Thus,

there is a possibility for the continuous harvesting of

mature palms at intervals, thereby sustaining sago

production.

0020Individual suckers at first grow into a rosette of

leaves. Then it produces a stout trunk. Sago palm

reaches sexual maturity at about 12–15 years. It is a

monocarpic plant – it flowers only once in its life and

then dies. Insects help to pollinate the flowers. The

fruits take about 1½–2 years to mature. Just before

the onset of flowering, the palm is harvested to obtain

maximum yield. During this stage, the palm converts

its stored nutrients into starch, which accumulates in

the trunk.

0021Edible starch is extracted from the pith-like center

of sago palm when the tree is about 12 years old.

During harvesting, the entire trunk is cut into pieces.

The marrow of the stem is then chopped out as finely

as possible and its starch is then washed out and

separated from the cellulose. Starch separated from

the stem is dried to yield sago meal.

0022Productivity of sago palm is four times that of

paddy (Oryza sativa). A single sago palm yields

about 150–300 kg sago. This starch is an important

item in the diet in some parts of Eastern Asia. It is

used in various food items and also to stiffen cloth

material in the textile industry. Desiccated products

made from sago starch can be stored for exceptionally

long periods. Sago starch has a multitude of uses.

Sago is widely used to produce sago pearls. Sago

pearls can be boiled, either alone or mixed with

other foods, and consumed directly as a carbohydrate

source. Sago is also widely used, together with rice,

corn, and potatoes, in the manufacture of noodles in

Malaysia. It is also used for the production of mono-

sodium glutamate, soft drinks, and various syrups.

The other uses of sago include the manufacture of

biodegradable plastics, ethanol, and citric acid. Sago

meal is very digestible and hence it can be used to feed

livestock, pigs, and even poultry.

0023In addition to the production of starch from the

stem, the large and strong leaves are useful. Leaves

are best for roof thatching, and for making bags,

baskets, and cages. Leaves contain long fibers (1.69–

3.59 mm) which have a high cellulose content. Hence,

it is also useful for papermaking.

0024The sago beetle is one pest which attacks the sago

palm. It bores into the trunks of the palms and lays its

eggs inside. But the natives consume the larvae of

these sago beetles as a highly esteemed delicacy.

They consume it either raw or in cooked form.

Thus, the pest attack has proved a boon to the local

population. Unfortunately, however, apes and wild

boars tend to damage palms at the young stage by

digging up and eating young palms during the sucker

stage.

See also: Alcohol: Properties and Determination; Amino

Acids: Properties and Occurrence; Bread: Breadmaking

5038 SAGO PALM

Processes; Flour: Analysis of Wheat Flours; Liver:

Structure and Function; Protein: Food Sources; Starch:

Sources and Processing; Toxins in Food – Naturally

Occurring; Wines: Production of Table Wines

Further Reading

Brandis D (1984) Indian Trees. London: Archibals Con-

stable.

Chamberlain CJ (1919) The Living Cycads. New York:

Hafner (Reprinted 1969).

Durlach J, Bac P, Durlach A, Bara M and Guiet-Bara A

(1997) Are age related neurodegenerative diseases linked

with various types of magnesium depletion? Magnes

Research 10(4): 339–353.

Eizirik DL and Kisby GE (1995) Cycad toxin-induced

damage of rodent and human pancreatic beta-cells. Bio-

chemistry and Pharmacology 31: 355–365.

Giddy C (1984) Cycads of South Africa, 2nd edn. Cape

Town: C. Struik.

Gobe GC (1994) Apoptosis in brain and gut tissue of mice

fed a seed preparation of the cycad Lepidozamia per-

offskyana. Biochemistry and Biophysical Research

Community 30: 327–333.

Macmillan HF (1994) Tropical Planting and Gardening.

Jodhpur, India: Scientific Publishers.

Pan M, Mabry TJ, Beagle JM and Mamiya BM (1997)

Nonprotein amino acids from Cycas revoluta. Phyto-

chemistry 45(3): 517–519.

Parker SP (1992) Encyclopedia of Science and Technology,

7th edn. New York: McGraw-Hill.

Watt JM and Breyer-Brandwijk MG (1962) The Medical

and Poisonous Plants of Southern and Eastern Africa,

2nd edn. Edinburgh and London: E & S Livingstone.

Whitten Tony and Whitten J (1996) Indonesian Heritage:

Plants. Singapore: Didier Miller.

Yoshimura K and Sagawa N (1918) The chemical constitu-

ents in Cycas revoluta, Thunb. 1. Nippon Kagaku Zasshi

[Chemical Society of Japan] 39: 1116–1121. Abstracted

in: Chemical Abstracts 13: 758–759.

SALAD CROPS

Contents

Dietary Importance

Leaf-types

Other Types of Salad Crops

Root, Bulb, and Tuber Crops

Dietary Importance

K Gupta and M K Rana, CCS Haryana Agricultural

University, Haryana, India

Introduction

0001 Vegetables that are normally consumed raw or un-

cooked are known as salad crops. They are seasonal,

attractive in appearance, and are valued for their

appetizing succulence, bulk, and nutritional import-

ance in human diet. Advances in education and com-

munication now mean that people have become

health-conscious and aware of quality of food for

their better health. Salad is becoming a popular add-

ition in the routine food habits of masses of people all

over the world. Salad vegetables consumed raw

supply more nutrients compared to cooked ones. All

salad vegetables are highly perishable in nature, and

their natural fresh form, which is preferred by quality-

conscious consumers, is rapidly lost. However, with

improved packaging technology, refrigerated trans-

portation systems, and advanced storage facilities,

the demand for salad vegetables, especially celery,

lettuce, and many others, is increasing day by day.

Types of Plant in the Salad Category

0002Since there is a vast number of salad vegetables grown

and consumed in various parts of the world, it is

essential that these must be so grouped that informa-

tion on them can be accessed readily. They may be

classified according to botanical traits, season of

growth, edible part of the plant used, and suitability

of the soil reaction for their successful cultivation

(Tables 1–3.) However, as salad vegetables are con-

sumed fresh, it may be pertinent to classify them

particularly on the basis of edible portions consumed

(Table 2).

SALAD CROPS/Dietary Importance 5039

Nutritional and Dietary Significance

0003 Salad vegetables, categorized as protective foods, are

rich in the macro- and micronutrients and fiber that

play a significant role in the maintenance of human

health. In contrast, salad vegetables are relatively

inexpensive. They are quite popular, easy to grow,

ship well, and have a long period of harvest but

short storage life. They are important for neutralizing

the acids produced in the stomach during the course

of digestion of meat, cheese, and other fatty foods.

They are of value as roughage that helps to prevent

constipation. A certain amount of bulky food is ne-

cessary for good health. Most salad vegetables, par-

ticularly the leaf types, such as celery, cabbage,

Chinese cabbage, lettuce, parsley, and spinach, are

characterized by a high water content and a relatively

high percentage of cellulose or fiber because of their

succulence and large bulk. The leafy and root salad

crops ordinarily help in the digestion of highly con-

centrated foods (Tables 4–7.).

0004 The carbohydrates of vegetables comprise starch

and sugars, mainly sucrose, glucose, and fructose,

which are easily available to the body and constitute

the main source of energy. Vegetables also provide

unsaturated lipids containing essential fatty acids

such as linoleic, linolenic, and arachidonic acid, which

are required for normal growth and maintenance of

the body. Salad vegetables provide a variety of pro-

teins to the human body.

0005Salad crops ranking highest in vitamin A are carrot,

turnip greens, spinach, mustard, and dandelion

(Tables 5–7.). Measured in levels of vitamins and

minerals, artichokes rank seventh among the top

vegetables. Spinach, kale, and collard contain high

levels of vitamins and minerals, particularly vitamin

A, calcium, phosphorus, and iron. A single serving

meets the daily requirement of vitamin A and C and

13% of the total calcium requirement of an adult.

0006Beet crops and carrots are considered primarily as a

source of carbohydrates, especially sugars. Carrot

roots contribute a significant proportion of the daily

requirement for vitamin A in US diets for adults, and

in addition to vitamins and minerals they provide

important dietary fiber.

0007Likewise, celery is also a good source of calcium,

phosphorus, and iron, and is rich in carotene, the

precursor of vitamin A, and in riboflavin, niacin,

and thiamin. One hundred grams of celery contain

protein 6.3 g, minerals 2.1 g, carbohydrates 1.6 g, and

fiber 1.4 g.

0008The nutritive value of cactus is comparable to those

of other popular fruits. They are rich in sugars (su-

crose 0.2%, glucose 7.0%, fructose 4.8% of fresh fruit

mass); vitamin C 22 mg; minerals (calcium 27.6 mg,

magnesium 27.2 mg, sodium 0.8 mg potassium

tbl0001 Table 1 Names of salad crops in nine languages

English Danish Dutch French German Italian Portuguese Spanish Swedish

Artichoke Artiskok Artisjok Artichauft Artischocke Carciofo Alcachofra Alcachofa Kronartskocks

Asparagus Asparges Asperge Asperge Spargel Asparago Aspargo Espa

rrago Sparris

Broccoli Broccoli Broccoli Chou-brocoli Brokkoli Cavolo

broccolo

Brocolos Bre

col Broccoli

Brussels

sprouts

Rosenkal Spruitbool Chou de

Bruxelles

Rosen kohl Cavolo di

Bruxelles

Couve de

Bruxelas

Col de

Bruselas

Brysselkal

Cabbage Kal Kool Chou Kohl Cavolo Couve Col repollo Kal

Celery Selleri Selderij Ce

leri Sellerie Sedano da

erbucci

Aipo Apio Selleri

Celeriac Knoldselleri Knolselderiji celeri-rave Knollensellerie Sedano rapa aipo de cabega Apio-nabo Rotselleri

Chinese

cabbage

Kinesisk kal Chinese kool Chou de

Chine

China kohl Cavolo

cinese

Couve da China Col de China Sallad kal

Endive Endivie Andijuie Chicore

frise

Endivie Indivia Chicoria Escarola Endiviesallet

Kale Gronkal Groene kool Chou vert Grunkohl Cavolo a

foglia

riccia

Couve galega

frisada

Sin cabeza Gronbal

Kohlrabi Knude kal Koolrabi Chou-rave Kohlrabi Cavolo-rapa Couve-rabano Colirabano Kalrabbi

Lettuce Salat Sla Laitue Salat Pattuga Alface Lechuga Sallad

Parsley Persille Peterselie Persil Petersilie Prezzemola

comune

Salsa frisada Perejil Persitja

Parsnip Pastinak Pastinaak Panais Pastsinake Pastinaca Pastinaca Pastinaca Pasternacka

Rhubarb Rabarber Rabarber Rhubarbe Rhabarber Rabarbaro Ruibarbo Ruibarbo Rabarber

Rutabaga Kalrabi Kool raap Chou-navet Kohlrube Navone Rutabaga Colinabo Kal rot

Spinach Spinat Spinazie Epinard Spinat Spinaci Espinafre Espinaca Spenat

Adapted from Stadhouders PJ (ed.) (1990) Elsevier’s Dictionary of Horticultural and Agricultural Plant Production. New York: Elsevier Science.

5040 SALAD CROPS/Dietary Importance

161 mg, phosphorus 15.4 mg, iron 1.5 mg 100 g

1

edible part) and amino acids.

0009 Chicory, chives, endive, kale, mustard, parsley

leaves, spinach, spring onions, and turnip greens are

excellent sources of vitamins A and C. Vitamin A

ranges from 2500 to 14 000 IU and vitamin C

from 30 to 180 mg per 100 g of the edible part

(Table 7). The plain-leaf endive (escarole) and the

dandelion (leaves) are highly rich in vitamin A

(14 000 IU) and contain vitamin C 100 and 35 mg

100 g

1

edible plant part, respectively. Sprouting

broccoli is most nutritious amongst the cole crops,

especially for calcium, iron, vitamins, and protein. As

regards quality, kohlrabi is similar to red cabbage but

superior to turnip and rutabaga as it has less bitter

principle.

0010Parsley and watercress are good sources of iron,

calcium, vitamins A and C, and riboflavin. Spinach,

tbl0002 Table 2 Botanical names, common names, and edible plant parts of vegetables/salad crops

Common name Botanical name Family Edible plant part

Monocotyledony

Onion family

Chive Allium schoenoprasum L. Alliaceae Leaf

Chinese chive Allium tuberosum Rottler ex. Sprengel Alliaceae Leaf and immature flower

Lily family

Asparagus Asparagus officinalis L. Liliaceae Shoot

Carpetweed family

New Zealand spinach Tetragonia tetragoniodes (Pall.) O Kuntze Aizoaceae Tender shoot and leaf

Dicotyledony

Carrot family

Chervil Anthriscus cerefolium (L.) Hoffm Apiaceae Leaf

Celery Apium graveolens L. var. dulce (Mill.) Pers Apiaceae Petiole leaf

Celeriac Apium graveolens L. var. rapaceum (Mill.) Gaud. Apiaceae Root, leaf

Fennel Foeniculum vulgare var. azoricum (Miller) Thell. Apiaceae Leaf

Florence fennel Foeniculum vulgare var. dulce Fiori Apiaceae Leaf base

Parsnip Pastinaca sativa L. Apiaceae Root, leaf

Parsley Petroselinum crispum (Mill.) nym. var. Crispum Apiaceae Leaf

Turnip-rooted parsley Petroselinum crispum (Mill.) nym. Tuberosum Apiaceae Root, leaf

Italian parsley Petroselinum crispum (Mill.) Nym. var. neapolitanum Apiaceae Leaf

Sunflower family

Endive Cichorium endiva L. Asteraceae Leaf

Chicory Cichorium intybus L. Asteraceae Leaf

Indian lettuce Lactuca indica L. Asteraceae Leaf

Asparagus lettuce Lactuca sativa L. var. asparagina Bailey Asteraceae Stem

Head lettuce Lactuca sativa L. var. capitata L. Asteraceae Leaf

Romaine lettuce Lactuca sativa L. var. longifolia Lam. Asteraceae Leaf

Dandelion Taraxacum officinale Wiggers Asteraceae Leaf, root

Mustard family

Curled mustard Brassica juncea (L.) Czernj. and Coss. var. crispi folia Brassicaceae Leaf

Small leaf mustard Brassica juncea (L.) Czernj. and Coss. var. foliosa Brassicaceae Leaf

Gemmiferous mustard Brassica juncea (L.) Czernj. and Coss. var. gemmifera Brassicaceae Stem and axillary bud

Involute mustard Brassica juncea (L.) Czernj. and Coss. var. insoluta Brassicaceae Leaf

Wide petiole mustard Brassica juncea (L.) Czernj. and Coss. var. patipa Li. Brassicaceae Leaf

Rutabaga Brassica napus L. var. napobrassica (L.) Reichb. Brassicaceae Root and leaf

Chinese kale Brassica oleracea L. var. alboglabra Bailey Brassicaceae Young flower stalk and leaf

White cabbage Brassica oleracea L. var. capitata L. Brassicaceae Leaf

Portuguese cabbage Brassica oleracea L. var. costala DC Brassicaceae Leaf and Inflorescence

Brussels sprouts Brassica oleracea L. var. gemmifera Zenk. Brassicaceae Axillary bud

Konlrabi Brassica oleracea L. var. gongylodes L. Brassicaceae Enlarged stem

Broccoli Brassica oleracea L. var. italica Plenck Brassicaceae Immature flower stalk

Spinach Brassica perviridis Bailey Brassicaceae Leaf

Chinese cabbage Brassica rapa L. var. pekinensis (Lour.) Olsson Brassicaceae Leaf

Garden cress Lepidium sativum L. Brassicaceae Leaf

Water cress Nasturtium officinale R. Br. Brassicaceae Leaf

Buckwheat family

Rhubarb Rheum rhabarbarum L. Polygonaceae Petiole

Valerian family

Italian corn salad Valerianella eriocarpa Desv. Polygonaceae Leaf

European corn salad Valerianella locusta (L.) Laterrade em. Betcke Polygonaceae Leaf

SALAD CROPS/Dietary Importance 5041

amongst the highly nutritious salad vegetables, is the

best source of vitamin A, providing 8100 IU

100 g

1

edible part. This amount also provides vita-

min C 51 mg and calcium 93 mg. Spinach is also a

good source of iron, phosphorus, and potassium,

with 3.1, 51, and 470 mg 100 g

1

edible plant

part, respectively. The quality of spinach is related

to its bright green color, tenderness, and flavor.

0011Turnip greens are considered valuable in the

diet primarily because of vitamin A and C contents

and the minerals calcium and iron. Leafy green

and yellow salad vegetables are important sources of

vitamin A and vitamin C, and contain appreciable

quantities of thiamin, niacin, and folic acid.

Industrial Use

0012The consistent availability of fresh and processed

vegetables in the world market indicates the im-

mense economic significance of the vegetable indus-

try as a major segment of the agricultural economy.

The dehydration of onions is done at industrial

level in the USA, especially in California. Aspara-

gus, tomatoes, lettuce, cucumber, and carrot are

produced commercially and processed into different

food products on an industrial scale. Some cauli-

flower, cabbage, rat-tailed radish, turnip, and carrot

are stored, canned, and shipped. The commercial

production of kale and spinach is confined along

the East Coast and in California, respectively.

Sauerkraut is the main processed product prepared

from cabbage.

0013Chinese cabbage is fermented to produce the

Korean dish kimchi, which includes either fermented

Chinese cabbage or fermented radish along with hot

peppers, garlic, and other ingredients. Commercial

quantities of chives are sold to processors, and

chopped leaves are mixed with cottage cheese or

cream cheese for the retail market. Lettuce leaves

are sometimes used as a substitute for tobacco in

cigarettes. Certain species of cactus are used for

making jam and syrups, alcoholic drinks, honey and

cheese, and fruit juices, and soap is made from the

leaves.

0014Celery has been used as a garnish and condiment in

Europe, Egypt, and China since old times. Probably

the plants used for these purposes were of the ‘smal-

lage’ type, with hollow, narrow petioles. Presently

tbl0003 Table 3 Classification based on life cycle and optimum

temperature (season)

Cycle/vegetable Season

Perennial Cool-season crops

Artichoke Hardy

Garlic Asparagus

Tomato Leek

Asparagus Parsley

Dandelion Rhubarb

Watercress Turnip

Chicory Cabbage

Onion Dandelion

Rhubarb Watercress

Chive Garlic

Onion

Biennial Kohlrabi

Beet Radish

Cabbage

Celery Half-hardy

Leek Carrot

Parsley Celeriac

Carrot Fennel

Celeriac Lettuce

Parsnip Artichoke

Cauliflower Beet

Florence fennel Celery

Kohlrabi Chicory

Turnip Endive

Annual Warm-season crops

Cucumber Tender–tomato

Lettuce Very tender – cucumber

Radish

Endive

Mustard

tbl0004 Table 4 Nutritional constituents of some salad crops (per 100 g edible part)

Macronutrients Vitamins Minerals

Water

(g)

Energy

(KJ(kcal))

Protein

(g)

Fat

(g)

Carbohydrate

(g)

A (IU) C (mg) B

(mg) B

(mg) Niacin

(mg)

Ca (mg) P (mg) Fe (mg)

Asparagus 91 100 (26) 2.5 0.2 5.0 900 33 0.18 0.20 1.5 22 62 10.0

Artichoke 85 84 (20) 2.7 0.2 2.3 160 11 0.06 0.08 0.8 53 78 15.0

Beet greens 91 100 (24) 2.2 0.3 4.6 6100 30 0.10 0.07 0.4 119 40 3.3

Beetroot 88 180 (43) 1.6 0.1 9.9 20 10 0.03 0.02 0.4 16 33 0.7

Kale 83 220 (53) 6.0 0.8 9.0 10 000 186 0.16 0.26 2.1 249 93 2.7

Mustard 90 130 (31) 3.0 0.5 5.6 7000 97 0.11 0.22 0.8 183 50 0.3

Rhubarb 95 67 (16) 0.6 0.1 3.7 100 9 0.03 0.39 0.3 96 18 0.8

Spinach 51 100 (26) 3.2 0.3 4.3 8100 51 0.10 0.22 0.6 93 51 3.1

Turnip greens 90 117 (28) 3.0 0.3 5.0 7600 139 0.21 – 0.8 246 58 1.8

5042 SALAD CROPS/Dietary Importance

the celery seeds are used as a pleasant flavoring agent

in tomato juice, sauces, soups, pickles, pastries,

salads, and other savoury dishes.

0015 Fennel (Foeniculum vulgare), a tall, hardy, aro-

matic perennial of the parsley family, is native to

southern Europe, and the Mediterranean area,

especially in the vicinity of the sea. Fennel is derived

from the Roman Foeniculum, a variety of fragrant

hay, and has been used as a condiment by the Chinese,

Indians, and Egyptians since long ago. F. vulgare var.

dulce Alef is cultivated in France for its young stems,

which are used in salads, and for its seeds; young

shoots are used as a vegetable and herb in Italy. The

leaves are feathery green, finely divided, and there are

golden yellow flowers. The fresh needle-shaped

leaves are used to flavor fish sauces and to garnish

mackerel.

Biological Properties

0016The medicinal significance of the above-mentioned

salad vegetables in human life is briefly described

below.

0017Asparagus shoots used as salad are useful to cleanse

the bowels and to cure jaundice and other stomach

disorders. The cactus may reduce sugar and cholesterol

levels in human blood and its seeds are used in pharma-

ceuticals. Globe artichoke is known for its medicinal

significance in reducing blood clotting and capillary

resistance, and in neutralization of some acids. The

juice extracted from globe artichokes is used as a

remedial treatment of gastrointestinal disorders.

0018Chicory is used for the remedy of warts. The boiled

leaves of dandelion are used as a diuretic and for liver,

kidney, and urinary disorders. The extract taken from

tbl0005 Table 5 Nutritional constituents of some salad crops (data per 100 g basis)

Crop Macronutrients Vitamins Minerals

Water

(g)

Energy

(KJ(kcal))

Protein (g) Fat

(g)

Carbo-

hydrate (g)

A (IU) C (mg) B

(mg) B

(mg) Niacin

(mg)

P(mg) Fe

Chicory 95 63 (15) 1.0 0.1 3.2 Trace 18 21 0.5

Chinese cabbage 95 58 (14) 1.2 0.1 3.0 150 25 0.05 0.04 0.6 43 40 0.6

Endive (curly) 93 84 (20) 1.7 0.1 4.1 3300 10 0.07 0.14 0.5 81 54 1.7

Garden cress 82 280 (67) 5.8 1.0 8.7 0.15 360 110 26.6

Lettuce 96 54 (13) 0.9 0.1 2.9 330 66 0.60 0.06 0.3 20 22 0.5

Mustard 90 130 (31) 3.0 0.5 5.6 7000 97 0.11 0.22 0.8 183 50 3.0

Parsley 85 184 (44) 3.6 0.6 8.5 8500 172 0.12 0.26 1.2 203 63 6.2

Spinach 91 109 (26) 3.2 0.3 4.3 8100 51 0.10 0.20 0.6 93 51 3.1

Watercress 89 138 (33) 2.9 0.2 4.9 2803 13 0.12 0.38 0.8 290 140 4.6

tbl0006 Table 6 Nutritional constituents of some salad crops (per 100 g edible portion)

Macronutrients Vitamins Minerals

Energy

(KJ(kcal))

Water

(g)

Protein (g) Fat (g) Carbo-

hydrate (g)

A(IU) B

(mg)

Niacin

(mg)

Carrot (roots) 130 (31) 89 0.8 0.2–6.6 1300 0.05 0.04 0.3 6 30 1.4 17 36

Celeriac roots 84 (20) 88 1.5 0.3 3.5 0 0.05 0.06 0.7 8 43 0.7 20 115

Celery self-

blanching

petioles

29 (7) 96 0.7 0.1 1.2 90 0.03 0.02 0.3 7 25 0.3 10 27

Green (petiole) 34 (8) 95 0.9 0.1 0.2 120 0.03 0.04 0.3 10 70 0.5 14 34

Cucumber fruit

(immature)

50 (12) 96 0.6 0.1 2.2 45 0.03 0.02 0.3 12 12 0.3 15 24

Florence fennel 63 (15) 93 1.1 0.1 2.6 100 0.04 0.02 0.4 9 44 0.8 23 38

Mustard greens 63 (15) 91 2.7 0.2 0.1 5300 0.08 0.11 0.8 70 140 2.0 48 45

Parsley leaves 67 (16) 90 2.2 0.3 1.3 5200 0.08 0.11 0.7 90 125 2.0 79 40

Radish (Chinese

winter icicle,

scarlet globe)

54–58

(13–14)

94 0.6–0.1 0.1 0.1–0.2 0 0.03 0.02 0.3 21 27 0.8 22 27

Tomato fruit 80 (19) 94 0.9 0.1 3.7 1700 0.10 0.02 0.6 21 6 0.3 10 16

Turnip (tops and

roots)

75 (18) 92 1.8 0.2 0.2 2700 0.05 0.07 0.5 70 125 1.5 45 45

Turnip greens 58 (14) 91 1.5 0.3 0.1 3400 0.07 0.10 0.6 60 90 1.1 31 42

SALAD CROPS/Dietary Importance 5043

spinach leaves is used to clean wounds and cure warts

in the UK. According to documentary evidence in the

literature, watercress has been used as a medicinal

plant from the first to the nineteenth centuries; its

principal use is as an antiscorbutic.

0019 The plants of the Brassicaceae family have been

claimed to possess cancer-preventive properties.

Increased consumption of broccoli, particularly

among women, appeared to improve survival against

lung cancer. Broccoli may also play an important role

in lowering the serum cholesterol levels. Plants of the

Crucifereae family contain S-methylcysteine sulfox-

ide, which is principally responsible for reducing

blood cholesterol levels in the body.

0020 Sulforaphane, a substance isolated from broccoli

and some other crucifers, helps to prevent the

growth of tumors developed by cancer-causing toxin

in mice. This may also have future applications in

human cancer treatment. The discovery of antithyr-

oid properties of cabbage causing goiter in rabbits

and other studies have related the occurrence of en-

demic goiter in humans in Belgium, western China,

and Canada and in animals to the consumption of

rutabaga, turnip, cabbage, kale, rape, and other

crucifers.

0021Researchers and breeders increasingly are con-

cerned about the concentration of glucosinolates in

cruciferous crops and their influence on humans and

animals. Glucosinolates as such are not injurious,

but their hydrolytic forms cause serious damage.

When plant cells are crushed, the myrosinase (thio-

glucoside-glucohydrolase) enzyme becomes active

and starts hydrolyzing the glucosinolates present in

the cells into various breakdown products, such as

isothiocyanates (mustard oils), thiocyanates, and ni-

trites. However, there is increasing evidence associat-

ing regular consumption of cabbage and other

Brassica vegetables with the reduced incidence of

some forms of cancer, probably due to the presence

of glucosinolate-derived products.

0022Several claims have been made that celery

seeds improve longevity and memory, eradicate skin

wounds and cure leprosy. It has also been used in the

UK for the treatment of rheumatism since the nine-

teenth century and is still used today as a nerve stimu-

lant in India. In the Orient, celery is used as the

medicine tranians; the boiled seed oil is inhaled as

vapor to cure headaches.

0023In past centuries fennel has been involved in medi-

cine as a carminative, stimulant, and stomachic, and

tbl0007 Table 7 Nutritional constituents of some salad crops (per 100 g edible portion)

Crop Macronutrients Vitamins Minerals

Energy

(KJ(kcal))

Water

(g)

Protein

(g)

Fat

(g)

Carbo-

hydrate (g)

(IU)

(mg)

Niacin

(mg)

Mg (mg) P (mg)

Cabbage (white,

red, Savoy),

20 92 1.2–2.0 0.1 0.4 200–1000 0.06 0.03 0.3 31–60 35–51 0.4–0.7 17–28 34–42

Cauliflower

(snowball)

22 90 2.2 0.3 0.9 40 0.08 0.06 0.6 72 30 0.5 12 60

Celtuce (leaves) 12 94 1.1 0.4 1.3 3500 0.09 0.12 0.5 33 59 0.8 38 34

Celtuce (stalk) 12 94 0.6 0.2 0.4 70 0.02 0.02 0.6 6 18 0.3 17 43

Chicory (leaves) 13 92 1.7 0.3 1.1 4000 0.06 0.10 0.5 24 100 0.9 30 47

Chicory (roots) 23 80 1.4 0.2 4.6 0 0.04 0.03 0.4 5 41 0.8 22 61

Chives (leaves) 20 92 2.8 0.6 1.1 6400 0.10 0.18 0.7 79 81 1.6 55 51

Endive (leaf

type)

11 95 1.3 0.2 1.2 2500 0.07 0.08 0.4 8 42 2.0 20 30

Endive (curled

type)

20 93 1.7 0.1 4.1 3300 0.07 0.14 0.5 10 81 1.7 54

Globe artichoke 20 83 2.7 2.3 2.3 160 0.08 0.06 0.8 11 53 1.5 48 78

Lettuce (butter

head)

11 96 1.2 0.2 1.2 1200 0.07 0.07 0.4 9 40 1.1 16 31

Lettuce (Cos/

Romaine)

16 94 1.6 0.2 2.1 2600 0.10 0.10 0.5 24 36 1.1 6 45

Lettuce (crisp

head) (Great

Lakes)

11 95 0.8 0.1 2.3 300 0.07 0.03 0.3 5 13 1.5 7 25

Onion (green

bulb)

21 90 1.3 0.2 4.0 330 0.06 0.05 0.3 32 62 0.5 25 43

Onion (green

leaves)

19 92 2.0 0.2 3.4 5000 0.07 0.14 0.2 45 80 1.0 24 30

In some cases, the analytical data relating to a given crop will appear to vary between articles. These differences may arise because of contrasts in

experimental techniques and/or raw materials employed by the original authors, and hence no attempt has been made to standardize the available

information.

5044 SALAD CROPS/Dietary Importance

as a cure for asthma, earache, toothache, rheumatism,

and cough. Even today it is being used as one of the

principal ingredients of ‘gripe water’ given to small

babies with digestive troubles and recommended by

herbalists to obese persons to reduce their weight.

0024 Leek and other vegetables of the genus Allium are

known to have aphrodisiac, blood purification, and

antithrombotic properties. The antibiotic effects of

Allium are due to the occurrence of sulfur com-

pounds, the bactericide being allicin. Onion has been

prized for its medicinal significance since Gerarde. In

the Great Herbal (1596) it was stated that ‘the juice of

onions snuffed up into the nose purges the head . . .

Forged with salt, rue and honey . . . it is good against

the biting of mad dogs . . . Anointed upon a bald head

in the sun brings up the hair again very speedily.’

Onion and garlic are used as folk medicine to cure

headaches, remove parasites, and for heart and circu-

latory disorders. In China, onion tea is taken to treat

headache, cholera, fever, and dysentery.

0025 Ancient Greek and Roman physicians used to cure

jaundice, headaches, and fevers with extract of wild

lettuce leaves. The extract for the treatment of

cancers of the uterus, liver, and other tumors was

also used. Unlike its close wild relatives, the culti-

vated form Lactuca sativa does not contain the bitter

principles sesquiterpene lactones, lactucin, and lactu-

picrin, having sedative properties. The other form of

lettuce, L. virosa L., is used in the pharmaceutical

industry for manufacturing the drug lactucarium.

0026 Rhubarb was prescribed in the literature for liver

and stomach disorders and to eradicate ringworm.

In Europe towards the end of the Middle Ages a huge

demand for the purgative drug derived from its dried

roots established a steady trade from central Asia.

Use in the Home as Raw or Industrially

Processed Food

0027 Freshness contributes prominently to crispiness and

taste of the salads that are customarily consumed

uncooked and in a raw state. A small fraction of

salad vegetables is also processed to convert them

into more delicious and durable food products. Or-

dinarily carrot, radish, turnip, cauliflower, cucumber,

and chillies are used to make pickles in addition to

their use in fresh salads. Celery, lettuce, onions, and

tomatoes, the most popular and important salad

vegetables, are available throughout the year. How-

ever, due to their medicinal importance in human

diet, carrots, cabbage, lettuce, mustard, onion, rhu-

barb, spinach, and watercress are used as salad.

0028 Artichoke is generally boiled or steamed before it is

consumed. However, some people prefer to take it

raw, when it is harvested at a young stage. The

bottoms and hearts are canned, frozen, marinated,

or kept in oil, and also used to produce pulp. Inulin,

the carbohydrate stored in the Jerusalem artichoke

tubers, on hydrolysis yields fructose, and is therefore

recommended for diabetes mellitus.

0029Numerous cultivated forms of cabbage (Brassica

oleracia var. capitata), with a wide range of features,

are available in nature. One or another variety,

e.g., Spring Green, January King, Savoy, Round-

Headed, White Cabbage, and Red Cabbage, can be

made available throughout the year. These are par-

ticularly used in the frozen-food industry and in

prepared salad. Many types of Chinese cabbage are

extremely important in the diets of Asians, used raw

in salads, cooked as greens, or fermented and pre-

served for later use. Fermented Chinese cabbage or

radish, along with hot pepper, garlic, and other ingre-

dients, forms the popular Korean dish kimchi.

0030In Mexico, the USA, Chile, Brazil, Spain, Italy,

Greece, and Northern Africa, certain genera of cactus

form an important part of people’s dietary require-

ments. The tender young pads of Opuntia and

Nopalea species of cactus, known as Nopalitos, are

extensively used as fresh green or salad vegetable and

fruit in Mexico and Texas. With the excellent quality

and flavor of fresh fruits, its young leaves serve as a

nutritious vegetable and salad dish and immature

fruits for making mock-gherkins.

0031Celery, chervil, leeks, and tomatoes are used to

make delicious soups and stews. Rhubarb and toma-

toes are also used in the preparation of sauces. Cher-

vil, chicory, leeks, fringed-leaf endive, fennel leaves,

and parsley are also used to flavor and garnish the

food. Lettuce, cabbage, radish, turnip, and cucumber

are industrially fermented to lettuce kraut, sauer-

kraut, sauerriipen, pawtsay, dill pickles, sour pickles,

and salt stocks. These fermented products are rela-

tively more appetizing, palatable, and flavorful than

the unfermented ones.

0032Finely ground powder prepared from dried, roasted

chicory roots is used as a substitute of coffee or

in blends with coffee. Chicory and endive are grown

as potherbs and their leaves are used to some extent

only. Chives are used in salads or in omelets and other

dishes. A close relative of the globe artichoke, a leafy

plant known as cardoon is grown for its edible

roots, or more often for its petioles, which may be

used either as a cooked vegetable or eaten raw

in salads.

0033Parsley, being appealing in flavor and taste, may be

used both on and in most foodstuffs except sweets, as

a seasoning and garnish in soups, salads, fish, meats,

and vegetables. Its foliage is in greater demand than

its seeds. In California, USA, West Germany, Belgium,

Hungary, Canada, Spain, and France, industrial

SALAD CROPS/Dietary Importance 5045

dehydrated parsley flakes are produced on a commer-

cial scale.

Toxic Substances

0034 Asparagus contains saponins and cholinesterase in-

hibitors. Carrot roots hold carotatoxin, which causes

neurotoxic symptoms. The leaves of rhubarb and

sorrel have a high content of oxalic acid, which on

ingestion reacts with soluble calcium and synthesizes

insoluble calcium oxalate, and as a result inhibits the

absorption of calcium. Hence, because of their tox-

icity, they should not be consumed in huge quantities.

The glucosides present in rhubarb appear to cause

strong irritation. White-colored oca tubers possess a

slightly higher oxalic acid content.

0035 Brassica plants possess cholinesterase enzyme in-

hibitors and a number of different goitrogens that

cause goiter in humans. Various species of mustard

contain glucosinolates, which are responsible for sev-

eral digestive disorders. Parsley and celery contain

psoralens and terpenoids, which cause dermatitis,

whereas some species of parsley and celery also con-

tain alkaloids and a cholinesterase enzyme inhibitor.

Lettuce is known to be an accumulator of a nitrate

form of nitrogen. Spinach contains oxalic acid and

saponins, and also tends to accumulate high levels of

nitrates, which may be reduced to nitrites. Nitrites

may convert hemoglobin to methemoglobin, interfer-

ing with the normal transportation of oxygen in the

blood.

0036 Some species of cucumber have a high content of

glycoalkaloid compounds, usually the glycosides

(cucurbitacins), which contribute a bitter taste to the

fruit, and their higher concentrations appear to be

very toxic. Hot pepper contains a high amount of

amide or resinoid capsaicin, which may sometimes

cause gastric disorders and skin irritation.

0037The cultivated forms of vegetables are generally

considered as safe if consumed appropriately, and

have many alimentary benefits that contribute to the

maintenance of health. However, excess ingestion of

beneficial substances can produce harmful effects,

whereas only low concentrations of some toxic com-

pounds can be endured by the body. The important

consideration is the dosage that makes the toxic com-

pound effective to produce injurious effects, and

where and how it acts in the body (Table 8).

See also: Onions and Related Crops; Tomatoes;

Vegetables of Temperate Climates: Cabbage and

Related Vegetables; Oriental Brassicas; Carrot, Parsnip,

and Beetroot