Food Biochemistry and Food Processing (2 edition)

BLBS102-c28 BLBS102-Simpson March 21, 2012 13:54 Trim: 276mm X 219mm Printer Name: Yet to Come

28 Biochemistry of Fruit Processing 555

Table 28.1.World Production of Fruit in 2002 in Metric Tons

Production

(Metric Tons) Africa Asia Europe America

Australia and

New Zealand World

Primary fruits 61,934,001 204,640,809 73,435,847 129,642,621 4,438,090 475,503,880

Apples 1,696,109 30,870,497 15,820,454 7,875,880 831,999 57,094,939

Bananas 7,140,629 35,766,134 446,600 15,372,622 250,000 69,832,378

Grapes 3,113,940 14,761,974 28,739,848 12,529,900 1,872,588 61,018,250

Mangoes 2,535,781 19,841,469 – 3,343,697 28,000 25,748,947

Oranges 4,920,544 14,177,590 6,180,846 38,402,953 444,500 64,128,523

Pears 530,547 10,996,503 3,626,020 1,759,538 202,597 17,115,205

Plums 173,946 5,385,634 2,661,194 1,069,953 24,000 9,314,727

Strawberries 171,132 325,670 1,276,192 1,157,540 21,300 3,237,533

Source: Calculated from FAOSTAT database. http://faostat.fao.org/default.aspx. Accessed on December 07, 2011.

result, the world production of primary fruits has increased from

384 million metric tons in 1992 to 475 million metric tons in

2002 (FAO). The world production of fruits in 2002 by regions

is shown in Table 28.1.

Advances in fruit processing technologies mostly occur in re-

sponse to consumer demands or improvement in the efficiency

of technology. Traditional methods of canning, freezing, and de-

hydration are progressively being replaced by fresh-cut, ready-

to-eat fruit preparations. The use of modified atmosphere and

irradiation also helps in extending the shelf life of produce.

Fruits are essential source of minerals, vitamins, and dietary

fiber. In addition to these components, they provide carbohy-

drates, and to a lesser extent, proteins. Fruits play an important

role in the digestion of meat, cheese, and other high-energy

foods by neutralizing the acids produced by the hydrolysis

of lipids.

FRUIT CLASSIFICATION

Fruits can be broadly grouped into three categories according to

their growth latitude, whether it is in temperate, subtropical, or

tropical regions.

1. Temperate zone fruits: Four subgroups can be distin-
   guished among temperate zone fruits that include small
   fruits and berries (e.g., grape, strawberry, blueberry, black-
   berry, cranberry), stone fruits (e.g., peach, plum, cherry,
   apricot, nectarine) and pome fruits, (e.g., apple, pear,
   Asian pear or Nashi, and European pear or quince).


2. Subtropical fruits: Two subgroups can be differentiated
   among subtropical fruits and include citrus fruits (e.g.,
   orange, grapefruit, lemon, tangerine, mandarin, lime,
   and pummelo), and noncitrus fruits (e.g., avocado, fig,
   kiwifruit, olive, pomegranate, and cherimoya).


3. Tropical fruits: Major tropical fruits include banana,
   mango, papaya, and pineapple. Minor tropical fruit in-
   clude passion fruit, cashew apple, guava, longan, lychee,
   mangosteen, carambola, rambutan, sapota, and so on.

CHEMICAL COMPOSITION OF FRUITS

Carbohydrates

Fruits typically contain between 10% and 25% carbohydrates,

less than 1% of protein and less than 0.5% of fat (Somogyi

et al. 1996b). Carbohydrates, sugars, and starches are broken

down into CO 2 , water, and energy during catabolism. The ma-

jor sources of carbohydrates are banana, plantain, date, raisin,

breadfruit, and jackfruit. Proteins and amino acids are contained

in dried apricot and fig, whereas fats are the major components

of avocado and olives. Sugars are the major carbohydrate com-

ponents of fruits and their composition vary from fruit to fruit.

In general, sucrose, glucose, and fructose are the major sugar

components present in fruits (Table 28.2). Several fruits also

contain sugar alcohols such as sorbitol.

Vitamins

Fruits and vegetables are major contributors to our daily vitamin

requirements. The nutrient contribution from a specific fruit or

vegetable is dependent on the amount of vitamins present in the

fruit or vegetable, as well as the amount consumed. The approx-

imate percentage contribution to daily vitamin intake from fruits

and vegetables is: vitamin A, 50%; thiamine, 60%; riboflavin,

30%; niacin, 50%; and vitamin C, 100% (Somogyi et al. 1996b).

Vitamins are sensitive to different processing conditions such as

exposure to heat, cold, reduced and high levels of oxygen, light,

free water, and mineral ions. Trimming, washing, blanching, and

canning can also cause the loss in vitamin content of fruits and

vegetables.

Minerals

Minerals found in fruits in general may not be fully nutrition-

ally available (e.g., calcium, found as calcium oxalate in certain

produce is not nutritionally available). Major minerals in fruits

are base-forming elements (K, Ca, Mg, Na) and acid-forming

elements (P, Cl, S). Minerals often present in microquantities are

Mn, Zn, Fe, Cu, Co, Mo, and I. Potassium is the most abundant

mineral in fruits, followed by calcium and magnesium. High

potassium is often associated with increased acidity and