Colour in grape juice is largely the result of anthocyanin pigments located in and near the skin. Moreover, the types and quantities of anthocyanin pigments are different among grape species. 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. Muscadine pigments are not as stable as those in Vinifera grapes, and this leads to the juice taking on a brownish color over time. The red muscadine grape anthocyanin pigments are extremely unstable under conventional warehouse storage temperatures. 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. Although muscadines generally lack sufficient pigments to make acceptable red wines, some research indicates a possibility of breeding cultivars that could have color as good as many bunch grapes.