Citrus Peel The intensely flavored citrus peel has long been used to flavor dishes (for example, dried orange peel in Sichuan cooking), and as a preparation in itself in the form of candied rind The outer epidermis contains the aromatic oil glands, while the underlying white, spongy, pectinrich albedo usually contains protective bitter phenolic substances Both the oil with its terpenes and the antioxidant phenolics are valuable phytochemicals (pp 256, 257) The bitters are water-soluble, while the oils are not Cooks can therefore leach the peel repeatedly with hot (rapid) or cold (slow) water to remove the bitter compounds, then gently cook the peel if still necessary to soften the albedo, and finally infuse it with a concentrated sugar syrup Through all this processing the waterinsoluble oils stay largely in the rind Marmalade, a sugar preserve that includes citrus peel, was originally a Portuguese fruit paste made with quince, but by the 18th century the high-pectin, readily gelled sour orange had begun to replace the quince Marmalade made with sweet oranges doesn’t gel as readily and lacks the characteristic flavor, including a bitterness that helps balance the sugar As is true for most fruits, the skin of citrus fruits is more easily removed from the underlying tissue by briefly immersing the fruit in simmering water Thick citrus rinds require an immersion of several minutes Heat softens the cell-wall cement that attaches rind to fruit, and may also encourage some enzymes to begin to dissolve the cement Kinds of Citrus Fruits Trees in the genus Citrus are wonderfully variable and prone to form hybrids with each other, which makes it a challenge for scientists to work out family relationships Currently it’s thought that the common domesticated citrus fruits all derive from just three parents: the citron Citrus ... require an immersion of several minutes Heat softens the cell-wall cement that attaches rind to fruit, and may also encourage some enzymes to begin to dissolve the cement Kinds of Citrus Fruits Trees in the. .. Citrus are wonderfully variable and prone to form hybrids with each other, which makes it a challenge for scientists to work out family relationships Currently it’s thought that the common domesticated... bitterness that helps balance the sugar As is true for most fruits, the skin of citrus fruits is more easily removed from the underlying tissue by briefly immersing the fruit in simmering water