Biology:Peach (fruit)

Peaches on a branch

Peach (cross section)

A peach is a soft, juicy and fleshy stone fruit produced by a peach tree.

History

Peaches were cultivated in China as far back as 8,000 years ago, with domestication at least 4,000 years ago. Some sources claim that peaches originated in China, whilst others claim that it originated in Iran.

Varieties

Hundreds of peach and nectarine cultivars are known. These are classified into two categories — the freestones and the clingstones, depending on whether the flesh sticks to the stone or not. Freestones are those whose flesh separates readily from the pit. Clingstones are those whose flesh clings tightly to the pit. Some cultivars are partially freestone and clingstone, so are called semifree. Freestone types are preferred for eating fresh, while clingstone types are for canning. The fruit flesh may be creamy white to deep yellow, to dark red; the hue and shade of the color depends on the cultivar.

Peaches with white flesh typically are very sweet with little acidity, while yellow-fleshed peaches typically have an acidic tang coupled with a sweet floral taste (sometimes described as the classic peach taste, which mellows as the peach ripens and softens), red fleshed varieties are typically flavourful and tangy but with a tart skin, though this also varies greatly. Yellow peaches have a sturdier flesh that is not as easily bruised. Both colors often have some red on their skin. Low-acid white-fleshed peaches are the most popular kinds in China, Japan, and neighbouring Asian countries, while Europeans and North Americans have historically favoured the acidic, yellow-fleshed cultivars.

Peach breeding has favored cultivars with more firmness, more red color, and shorter fuzz on the fruit surface. These characteristics ease shipping and improve supermarket sales due to eye appeal. However, this selection process has not necessarily led to increased flavor. Peaches have a short shelf life, so commercial growers typically plant a mix of different cultivars to have fruit to ship all season long.

Nectarines

White nectarines, whole and cut open

The variety P. persica var. nucipersica (or var. nectarina), commonly called nectarine, has a smooth skin. It is on occasion referred to as a "shaved peach" or "fuzzless peach", due to its lack of fuzz or short hairs. Though fuzzy peaches and nectarines are regarded commercially as different fruits, with nectarines often erroneously believed to be a crossbreed between peaches and plums, or a "peach with a plum skin", nectarines belong to the same species as peaches. Several genetic studies have concluded nectarines are produced due to a recessive allele, whereas a fuzzy peach skin is dominant. Nectarines have arisen many times from peach trees, often as bud sports.

As with peaches, nectarines can be white or yellow, and clingstone or freestone. On average, nectarines are slightly smaller and sweeter than peaches, but with much overlap. The lack of skin fuzz can make nectarine skins appear more reddish than those of peaches, contributing to the fruit's plum-like appearance. The lack of down on nectarines' skin also means their skin is more easily bruised than peaches.

The history of the nectarine is unclear; the first recorded mention in English is from 1616, but they had probably been grown much earlier within the native range of the peach in central and eastern Asia. Although one source states that nectarines were introduced into the United States by David Fairchild of the Department of Agriculture in 1906, a number of colonial-era newspaper articles make reference to nectarines being grown in the United States prior to the Revolutionary War. 28 March 1768 edition of the New York Gazette (p. 3), for example, mentions a farm in Jamaica, Long Island, New York, where nectarines were grown.

Peach production, 2017
Region	(tonnes)
China	14,294,973
Spain	1,799,685
Italy	1,250,721
Greece	938,000
United States	775,189
Turkey	771,459
Iran	422,365
World	24,665,205
Source: FAOSTAT of the United Nations

Peacherines

Peacherine is claimed to be a cross between a peach and a nectarine, and are marketed in Australia and New Zealand. The fruit is intermediate in appearance between a peach and a nectarine, large and brightly colored like a red peach. The flesh of the fruit is usually yellow, but white varieties also exist. The Koanga Institute lists varieties that ripen in the Southern Hemisphere in February and March.

In 1909, Pacific Monthly mentioned peacherines in a news bulletin for California. Louise Pound, in 1920, claimed the term peacherine is an example of language stunt.

Flat peaches

Flat peaches or pan-tao have a flattened shape in contrast to ordinary rounded peaches.

Production

In 2017, world production of peaches was 24.7 million tonnes, led by China with 58% of the total. Spain and Italy each produced more than one million tonnes.

Nutrition

Peaches, raw

Nutritional value per 100 g (3.5 oz)
Energy	165 kJ (39 kcal)
Carbohydrates	9.54 g
Sugars	8.39 g
Dietary fiber	1.5 g
Fat	0.25 g
Protein	0.91 g
Vitamins	Quantity %DV†
Vitamin A equiv. beta-Carotene	2% 16 μg 2% 162 μg
Thiamine (B1)	2% 0.024 mg
Riboflavin (B2)	3% 0.031 mg
Niacin (B3)	5% 0.806 mg
Pantothenic acid (B5)	3% 0.153 mg
Vitamin B6	2% 0.025 mg
Folate (B9)	1% 4 μg
Choline	1% 6.1 mg
Vitamin C	8% 6.6 mg
Vitamin E	5% 0.73 mg
Vitamin K	2% 2.6 μg
Minerals	Quantity %DV†
Calcium	1% 6 mg
Iron	2% 0.25 mg
Magnesium	3% 9 mg
Manganese	3% 0.061 mg
Phosphorus	3% 20 mg
Potassium	4% 190 mg
Sodium	0% 0 mg
Zinc	2% 0.17 mg
Other constituents	Quantity
Water	89 g
Link to USDA Database entry
Units μg = micrograms • mg = milligrams IU = International units
†Percentages are roughly approximated using US recommendations for adults. Source: USDA Nutrient Database

Raw peach flesh is 89% water, 10% carbohydrates, 1% protein, and contains negligible fat. A medium raw peach, weighing 100 g (3.5 oz), supplies 39 calories, and contains small amounts of essential nutrients, but none is a significant proportion of the Daily Value (DV, right table). A raw nectarine has similar low content of nutrients. The glycemic load of an average peach (120 grams) is 5, similar to other low-sugar fruits.

Phytochemicals

Total polyphenols in mg per 100 g of fresh weight were 14–102 in white-flesh nectarines, 18–54 in yellow-flesh nectarines, 28–111 in white-flesh peaches, and 21–61 mg per 100 g in yellow-flesh peaches. The major phenolic compounds identified in peach are chlorogenic acid, catechins and epicatechins, with other compounds, identified by HPLC, including gallic acid and ellagic acid. Rutin and isoquercetin are the primary flavonols found in clingstone peaches.

Red-fleshed peaches are rich in anthocyanins, particularly cyanidin glucosides in six peach and six nectarine cultivars and malvin glycosides in clingstone peaches. As with many other members of the rose family, peach seeds contain cyanogenic glycosides, including amygdalin (note the subgenus designation: Amygdalus). These substances are capable of decomposing into a sugar molecule and hydrogen cyanide gas. While peach seeds are not the most toxic within the rose family (see bitter almond), large consumption of these chemicals from any source is potentially hazardous to animal and human health.

Peach allergy or intolerance is a relatively common form of hypersensitivity to proteins contained in peaches and related fruits (such as almonds). Symptoms range from local effects (e.g. oral allergy syndrome, contact urticaria) to more severe systemic reactions, including anaphylaxis (e.g. urticaria, angioedema, gastrointestinal and respiratory symptoms). Adverse reactions are related to the "freshness" of the fruit: peeled or canned fruit may be tolerated.

Aroma

Some 110 chemical compounds contribute to peach aroma, including alcohols, ketones, aldehydes, esters, polyphenols and terpenoids.

Peaches in art

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  Girl with Peaches
  Valentin Serov
  1887

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  Jar of Peaches
  Claude Monet
  1866

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  Still Life Basket of Peaches
  Raphaelle Peale
  1816.

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  Portrait of Isabella and John Stewart
  Charles Willson Peale
  1774.