The peach tree (Prunus persica) is a species of Prunus native to China that bears an edible juicy fruit called a peach. It is a deciduous tree growing to 4–10 m (13–33 ft) tall, belonging to the subfamily Prunoideae of the family Rosaceae. It is classified with the almond in the subgenus Amygdalus within the genus Prunus, distinguished from the other subgenera by the corrugated seed shell.
The leaves are lanceolate, 7–16 cm (2.8–6.3 in) long, 2–3 cm (0.79–1.2 in) broad, pinnately veined. The flowers are produced in early spring before the leaves; they are solitary or paired, 2.5–3 cm diameter, pink, with five petals. The fruit has yellow or whitish flesh, a delicate aroma, and a skin that is either velvety (peaches) or smooth (nectarines) in different cultivars. The flesh is very delicate and easily bruised in some cultivars, but is fairly firm in some commercial varieties, especially when green. The single, large seed is red-brown, oval shaped, approximately 1.3–2 cm long, and is surrounded by a wood-like husk. Peaches, along with cherries, plums and apricots, are stone fruits (drupes).
The scientific name persica, along with the word “peach” itself and its cognates in many European languages, derives from an early European belief that peaches were native to Persia (now Iran). The modern botanical consensus is that they originate in China, and were introduced to Persia and the Mediterranean region along the Silk Road before Christian times. Cultivated peaches are divided into clingstones and freestones, depending on whether the flesh sticks to the stone or not; both can have either white or yellow flesh. Peaches with white flesh typically are very sweet with little acidity, while yellow-fleshed peaches typically have an acidic tang coupled with sweetness, though this also varies greatly. Both colours 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 kinds.
Nectarines
The nectarine cultivar group of peaches have a smooth skin. It is often referred to as a “shaved peach”, “fuzzy-less peach” or “shaven 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”, they belong to the same species as peaches. Several genetic studies have concluded nectarines are created due to a recessive gene, 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. The 28 March 1768 edition of the “New York Gazette” (pg 3.), for example, mentions a farm in Jamaica, Long Island, New York, where nectarines were grown.
Nutrition and research
A medium peach 75 g (2.6 oz), has 30 Cal, 7 g of carbohydrate (6 g sugars and 1 g fibre), 1 g of protein, 140 mg of potassium, and 8% of the daily value (DV) for vitamin C. 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, that dubious honour going to the bitter almond, large doses of these chemicals from any source are hazardous to human health.
Peach allergy or intolerance is a relatively common form of hypersensitivity to proteins contained in peaches and related fruit (almonds). Symptoms range from local symptoms (e.g. oral allergy syndrome, contact urticaria) to systemic symptoms, 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.