Muscadine Grape

Muscadines or Vitis rotundifolia are a grapevine species native to the present day southeastern United States that has been extensively cultivated since the 16th Century. Its recognized range in the United States extends from New York south to Florida, and west to Missouri, Kansas, Arkansas, Oklahoma and Texas. They are well adapted to their native warm and humid climate; they need fewer chilling hours than better known varieties and they thrive on summer heat.

Muscadine berries range from bronze to dark purple to black in color when ripe. However, many wild varieties stay green through maturity. They have skin sufficiently tough that eating the raw fruit often involves biting a small hole in the skin to suck out the pulp inside. Muscadines are not only eaten fresh, but also are used in making wine, juice, and jelly.

Muscadine grapes are rich sources of polyphenols and other nutrients studied for their potential health benefits.Reports have indicated that muscadine grapes may contain high concentrations of resveratrol which a polyphenol with reported beneficial health effects and that wines produced from these grapes, both red and white, may contain more than 40 mg/L of resveratrol. However, subsequent studies have found no or little resveratrol in different varieties of muscadine grapes.

In a natural setting, muscadines are important plants for improving wildlife habitat by providing cover, browse, and fruit for a wide variety of animals.



Taxonomy

Although in the same genus Vitis with the other grapevine species, muscadines belong to a separate subgenus, Muscadinia (the other grapevine species belong to subgenus Vitis), and some have suggested giving it standing as a genus of its own. Some taxonomists have also suggested splitting two additional species off from Vitis rotundifolia, Vitis munsoniana and Vitis popenoei. All have 40 chromosomes, rather than 38, are generally not cross-compatibile with other Vitis species, and most hybrids between the subgenera are sterile. A few, however, are at least moderately fertile, and have been used in breeding.

Cultivars

There are over 300 muscadine cultivars growing in the southern states. These include bronze, black and red varieties and consist of common grapes and patented grapes.

Unlike most cultivated grapevines, many muscadine cultivars are pistillate, requiring a pollenizer to set fruit. A few, however, such as 'Carlos' and 'Noble', are perfect-flowered, produce fruit with their own pollen, and may also pollinate pistillate cultivars.

Cultivars include Black Beauty, Carlos, Cowart,Flowers, Fry, Granny Val, Ison, James, Jumbo, Magnolia, Memory the first found on T.S. Memory's farm in 1868 in Whiteville, NC, Mish, Nesbitt, Scuppernong, Summit, Supreme, Thomas, Produced by the University of Florida, the cultivar, 'Southern Home', contains both muscadine and subgenus Vitis in its background.

Crops can be started in 3 to 5 years. Commercial yields of 3 to 7 tonnes per hectare in which 8 to 18 tons per acre are possible. Muscadines grow best in fertile sandy loam and alluvial soils. They grow wild in well-drained bottom lands that are not subject to extended drought or waterlogging. They are also resistant to pests and diseases, including Pierce's disease, which can destroy other grape species. Muscadine is one of the grape species most resistant to Phylloxera, an insect that can kill roots of grapevines.

Wine

Muscadines have been used for making commercial fine wines and port wines dating back to the 15th Century in and around St. Augustine, Florida. Today, vineyards throughout the Southeast produce muscadine wines of various qualities.
The typical muscadine wine is sweet because vintners traditionally add sugar during the winemaking process; the wine is often considered a dessert wine although some drier varieties exist. The term scuppernong refers to a large bronze type of muscadine originally grown in North Carolina; it is also used in making wine, principally dry red table wine.

While not one of the most widely marketed varietals produced, the visibility of muscadine wine has benefited from the discovery that it appears to provide greater amounts of antioxidants than many better-known red wines. In particular, muscadine wines both red and white contain over five times more resveratrol than ordinary red wines: more than 40 mg/L compared to between 0.2 and 5.8 mg/L.

Because grape vines synthesize resveratrol as a defense, it has been claimed in sales literature that the use of pesticides greatly reduces the grape's resveratrol content; however, scientific studies either find no correlation between pesticide use and resveratrol, or find that pesticide use has only a weak effect.

Other products

Other traditional Southern US muscadine-derived food products are readily available: jelly, preserves, syrup, and sauce. The fresh grape is available in season, September and October. The juice is available, white and colored. Raisins are used to make the wine usually known as scuppernong, but are not generally available.

Resveratrol and other polyphenols

As muscadine grapes are notable for their highly pigmented, thick skins in which the content of polyphenols is known to be high , research interest in describing these phytochemicals is significant.

Resveratrol is produced by many plants, apparently due to its antifungal properties. It is found in widely varying amounts in grapes primarily the skins. Ordinary non-muscadine red wine contains between 0.2 and 5.8 mg/L, depending on the grape variety, while white wine has much less - the reason being that red wine is fermented with the skins, allowing the wine to absorb the resveratrol, whereas white wine is fermented after the skin has been removed. Wines produced from muscadine grapes, both red and white, may contain more than 40 mg/L.

In grapes, resveratrol is found primarily in the skin and seeds. This is particularly true for muscadine grapes, whose skin and seeds have been reported to have about one hundred times the concentration as the pulp. The amount found in grape skins also varies with the grape cultivar, its geographic origin, and exposure to fungal infection. The amount of fermentation time a wine spends in contact with grape skins is an important determinant of its resveratrol content. According to "Le Blanc et al., 2006", muscadine table wines contain between 9 and 32 mg/L of cis resveratrol and between 5 and 13 mg/L trans resveratrol.

Several studies have detected substantial amounts of resveratrol in muscadine berries and seeds. Concentrations for the berries without seeds have been reported to range from 3 to 24 parts per million in dried samples. Containing an average of 43 ppm, the high seed concentration of resveratrol could be significant during muscadine wine making when the fermenting wine is in contact with seeds. Muscadine pomace, the solids left after pressing, contained 18 to 84 ppm in dried samples. A purée made from the pomace with the seeds removed contained 10 to 62 ppm. Muscadine wine was reported to have from 0.7 to 2 mg/L resveratrol for red wines and 0.3 to 1 mg/L resveratrol for white wine. For juices, resveratrol was found in concentrations ranging from 3 to 13 mg/L. While initial reports have indicated that muscadine grapes could contain high concentrations of resveratrol, subsequent studies have found no or little resveratrol in different varieties of muscadine grapes.

Other muscadine polyphenols include:

anthocyanins such as delphinidin and petunidin
tannins
quercetin
catechins and epicatechin particularly in seeds
gallic acid
ellagic acid particularly in skin
ellagic acid glycosides
ellagitannins
myricetin particularly in leaves
kaempferol
Interestingly, the rank order of total phenolic content among muscadine components was found to be seeds, skins, leaves and pulp.

Other nutrients

A Mississippi State University nutritionist reported that a purée of muscadine skins and pulp is an excellent source also of dietary fiber, essential minerals and carbohydrates and is low in fat. Muscadine purée powder has more dietary fiber than oat or rice bran.

Anti-cancer evidence

As one of nature's richest sources of polyphenolic antioxidants, muscadines have been studied for their potential health benefits which include preliminary evidence for effects against cancer mechanisms. To date, in vitro studies have shown positive effects of muscadine phenolics against blood, colon and prostate cancers.