Chemical Composition and Fermentation Studies of Citron '

The citron, Citrus medica Linn., originally introduced into southern Europe from the Orient, is now grown in limited quantities in Puerto Rico, California, and Florida. When ripe the fruit resembles a giant lemon. It is normally picked while it is somewhat immature and the epicarp is still green. The essential oils in the fruit are oil of citron and oil of cedra, which are present in oil sacs in the skin (fig. 1). The thick mesocarp is used for preserving; the pulpy center containing the seeds is discarded. The true citron should not be confused with the citron melon, a variety of Citrullus vulgaris, the common watermelon. The true citron is inedible in the raw state. In preparation for preserving it is usually halved and subjected to a prolonged fermentation in either sea water or a 5to 10-percent salt brine. The fermentation removes the bitterness, clears the mesocarp, softens the tissues, and makes it possible for them to absorb high concentrations of sugar. Following the removal of salt from the peel, the preserving process consists essentially in gradually increasing the sugar content of the peel by immersion in a series of sugar sirups of increasing strength. After draining and drying, the peel is ready for market under the name of either preserved or candied citron. Because of the paucity of published data on the fermentation and the chemical and nutritive properties of citron, a laboratory study involving these subjects seemed desirable. A review of the literature showed no analyses of fresh citron, few determinations of the mineral constituents of preserved citron, and no data at all on the vitamins. Furthermore, the findings of Chadefaux (3)^ and Hollande and Chadefaux (8) on the fermentation of Corsican citron appeared not to have been substantiated by other investigators.