Fruit of Peaches (Prunus persica L. Batsch)

A soft, sweet fruit that grows on trees, believed to have originated in China. Peach, along with its smooth-skin mutant nectarine, is one of the most important temperature stone fruits grown in the world.

The large-sized fruit varieties are grown mainly in the temperate regions of the world, where they find congenial environmental conditions for the healthy development of the plant and fruit.

The characteristic flavor of the peach is due to the effect of a rather complex mixture of substances upon the organs of taste.

Perception of the sugars, acid, tannins and astringent substances permits the formation of a judgments as to the ratio which these constituents bear to one another and consequently of the palatability of the fruit.

Fresh peaches should be fairly firm or becoming slightly soft. The skin color between the red areas should be red or at least creamy. The pulp is of a yellowish color, full of high-flavored juice; the fleshy part thick and the stone small.

Reddish color alone is not a sign of ripeness, but a mark of certain varieties. At home, peaches should be kept at broom temperature 3 or 4 days until fully ripe, then refrigerated.

Peaches are excellent when consumed fresh. They also have many culinary uses, mainly as desserts but also in pickling and in chutney and preserved in brandy.

The fruits are high in vitamins A and C and have fewer calories that apples and pears.
Fruit of Peaches (Prunus persica L. Batsch)

Optimum ripening of fruit

Fruit ripening can be considered as a presenescence phase since the fruit flesh will ultimately senesce with dispersal of the seeds. Each fruit has an optimum ripening stage at which it contains sugars, firmness, flavor and color at the most preferred levels.

Degradation of chlorophyll with or without synthesis of carotenoids is part of the ripening process in some fruits while other fruits like kiwi and avocado remains green.

Fruit that goes past its optimum ripeness enter senescence, a stage of overripeness and breakdown. The initiation of senescence is probably localized somewhere within the cytoplasm. Many of the conditions use to describe fruit senescence, such as color change that occurs when chloroplasts change to chromoplasts. In this stage, the texture loses its firmness, succulence is diminished, and sugar, acid, and aroma elements generally all decline in concentration.

Flavor and color are also changing during ripening due to the synthesis of aromatic volatile compounds and phenolics.

Some fruits like the banana have an early senescence, and deterioration, once begun, is rapid. On the other hand, some fruit, like apples, resists the onset of senescence can be controlled by keeping the fruit at the lowest temperature that it can tolerate and by increasing the amount of atmospheric carbon dioxide to a control level. Too much carbon dioxide can be harmful.

For most fruit the optimum ripening temperature is between 15 and 25 °C independent of ripening behavior (climacteric-nonclimacteric) or sensitive to chilling injury.
Optimum ripening of fruit

Properties of grapefruit

Grapefruit and its juice have been popular worldwide for their refreshing flavor and beneficial health effects. Grapefruit, common name for the fruit of a variety of citrus. The variety probably originated in Jamaica; it was introduced to Florida in the 16th century by Spaniards.

The grapefruit is an evergreen tree, Citrus paradise, of the Rutaceae family, and its fruit is the largest of the commercially grown citrus fruit.

Grapefruits are borne on small trees that rarely exceed 6 m (20 ft) in height. The dense foliage consists of shiny, dark-green leaves with winged petioles. The large white flowers produce yellow, globe-shaped fruit in grapelike clusters.

The grapefruit is known for its sour to semi-sour flavor, It contains grapefruit mercaptan, a sulphur, which in turn contain sterpene, influencing its flavor.

The fruits vary from 10 to 15 cm (4 to 6 in) in diameter and consist of a juicy, acid pulp surrounded by a leathery rind. The color of the pulp is normally light yellow, but a few pink-pulped varieties have been developed.

More than 20 varieties of grapefruit have been propagated in the United States. The major yellow-pulped varieties are Duncan and Marsh; the major pink-pulped varieties are Ruby and Webb.

The grapefruit is readily crossed with other members of the citrus genus. The tangelo, a Florida juice fruit, was produced by fertilization of grapefruit flowers with mandarin orange pollen.

The highest consumption of grapefruit and its juice is in China and the United States, being commonly served at breakfast.

In the United States, grapefruit juice is regularly consumed by about 21% of all households. It has been reported that about half of the total grapefruit production in the United States is mainly processed into juice.
Properties of grapefruit