Food Biochemistry and Food Processing (2 edition)

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29 Biochemistry of Vegetable Processing 571

Table 29.2.World Production of Selected Vegetables in

2002 in Metric Tons (Mt)

Production in 2002

Countries Fresh Vegetable Tomatoes

World 233,223,758 108,499,056

Africa 12,387,390 12,428,174

Asia 199,192,449 53,290,273

Australia 80,000 400,000

Canada 124,000 690,000

European Union (15) 8,462,000 14,534,582

New Zealand 120,000 87,000

North and Central America 2,023,558 15,837,877

South America 3,503,611 6,481,410

United States of America 1,060,000 12,266,810

kilograms of vegetables (including potatoes), up from 106 kg

a decade earlier. Potatoes represented 35% of all vegetables

consumed. In 2008, greater than 50% of women and nearly

40% of men reported to have more than 5 servings of fruits

and vegetables per day. (http://www.statcan.gc.ca/pub/82-229-x/

2009001/deter/fvc-eng.htm.) The world production of certain

vegetables is shown in Tables 29.2 and 29.3. From 2002 to 2005,

the increase in vegetable production observed was primarily due

to an increase in production of potatoes (Fig. 29.1).

In the United States, consumption of fresh vegetables

(excluding potatoes) has increased from 60 kg in 1986 to 72 kg

in 2003. In 2003, the most consumed fresh vegetable was

head lettuce at 12 kg, followed by onions at 9 kg and fresh

tomatoes at 8 kg. In the same year, the consumption of pro-

cessed tomatoes per capita was 35 kg and processed sweet corn

9.5 kg. In Canada, the consumption of fresh vegetables

(excluding potatoes) has been increasing steadily reaching

70.2 kg/capita in 1997 from 41 kg/capita in 1971. Also in 1997,

the consumption of fresh vegetables has declined 2.4% from

the amount of fresh vegetables consumed in 1996 (71.9 kg/

capita). Lettuce (16%) is the most consumed fresh veg-

etable followed by onions (12.1%), carrots (12.0%), tomatoes

(11.6%), and cabbage (8.1%). Brussels sprouts, parsnips, as-

paragus, beets, and peas each represent less than 1.0% of

Canadian fresh vegetable diet. On a per capita basis, Canada

has one of the highest consumption rates of fresh vegeta-

bles in the world. Frozen vegetable consumption has de-

Table 29.3.Production of Tomato in North America

Tomato Production (Mt) Year 2002

World 108,499,056

Canada 690,000

United States of America 12,266,810

Mexico 2,083,558

Source: Food and Agricultural Organization (FAO).

Table 29.4.Classification of Vegetables

Types of Vegetables Examples

Earth vegetables

Roots Sweet potatoes, carrots

Modified stems

Corms Taro

Tubers Potatoes

Modified buds

Bulbs Onions, garlic

Herbage vegetables

Leaves Cabbage, spinach, lettuce

Petioles (leaf stalk) Celery, rhubarb

Flower buds Cauliflower, artichokes

Sprouts, shoots (young stems) Asparagus, bamboo shoots

Fruit vegetables

Legumes Peas, green beans

Cereal Sweet corn

Vine fruits Squash, cucumber

Berry fruits Tomato, eggplant

Tree fruits Avocado, breadfruit

clined 3.4% to 5.6 kg/capita while canned vegetables and

vegetable juices have increased 2.4% to 12.9 kg/capita for

the same period. Vegetable purchases by consumers represent

6.6% of total food expenditures, virtually unchanged in the

past 10 years.

CLASSIFICATION OF VEGETABLES

Vegetables can be classified according to the part of the plant

from which they are derived, such as leaves, roots, stems, and

buds as shown in Table 29.4. They also can be classified into

“wet” or “dry” crops. Wet crops such as celery or lettuce have

water as their major component, whereas dry crops such as

soybeans have carbohydrates, protein, and fat as their major

constituents, and relatively low amount of water. Soybeans, for

example, are composed of 36% protein, 35% carbohydrate, 19%

fat, and 10% water. Wet crops tend to perish more rapidly com-

pared to dry crops.

CHEMICAL COMPOSITION OF

VEGETABLES

Fresh vegetables contain more than 70% water, and very fre-

quently greater than 85%. Beans and other dry crops are excep-

tions. The protein content is often less than 3.5% and the fat

content less than 0.5%. Vegetables are also important sources of

digestible and indigestible carbohydrate, as well as of minerals

and vitamins. They contain the precursor of vitamin A, beta-

carotene, and other carotenoids. Carrots are one of the richest

sources of beta-carotene (provitamin A).