Produce Degradation Pathways and Prevention

Nutrient Loss 229

8.2.2.1 Minerals

About 14 mineral elements are considered to be essential for good nutrition, prima-
rily as body process regulators (Mahan and Escott-Stump, 2002): calcium, sodium,
zinc, iodine, copper, phosphorus, potassium, sulfur, fluoride, manganese, iron, mag-
nesium, cobalt, and chloride. The concentration of minerals in fruits and vegetables
varies depending on agronomical practices, types of soils, and the stage of maturity
(Salunkhe et al., 1991). Overall, vegetables contribute moderate amounts of potas-
sium, phosphorus, and calcium, while fruits contribute moderate amounts of potas-
sium to the diet. Potassium in fruits occurs in combination with various organic
acids (Hugo and Du, 1969). In fruits, the potassium/organic acid balance controls
the pH of the tissue.

8.2.2.2 Vitamins

Vitamins are organic nutrients that are usually required in small quantities. They
play various roles in biochemical reactions in cells within the body. Fruits and
vegetables contribute 20 to 90% of various vitamins in the food supply (see Figure
8.1). For example, they are good sources of provitamin A, thiamin, riboflavin, niacin,
pantothenic acid, and folic acid (Salunkhe et al., 1991). In general, deep yellow, red,
orange, and dark green fruits and vegetables, such as mangoes, carrots, sweet potatoes,

FIGURE 8.1Percentage of nutritional contribution of fruits and vegetables of the total food
supply. (Modified from Salunkhe et al. (1991), Storage, Processing, and Nutritional Quality
of Fruits and Vegetables, Vol. 1, CRC Press, Boca Raton, FL.)

0

10

20

30

40

50

60

70

80

90

100

Acorbic acid

Vitamin AVitamin B6Magnesium

Iron

Thiamin NiacinCaloriesProtein

Fat

Major nutrients

Percent of total food supply