Enzymatic Peeling of Citrus Fruits: Factors Affecting Degradation of the Albedo

The environmental problems caused by chemical peeling of citrus, together with the establishment of new applications for enzymatic preparations with degradative activities led several investigators to study enzymatic peeling as an alternative to traditional chemical peeling. The principle of enzymatic peeling is based on the digestion, through an enzymatic preparation, of the pectic substances existing in the cell wall of plants. The efficiency rate of enzymatic peeling is influenced by the morphological characteristics of citrus fruits, the correct vacuum application and the incubation time, as well as by the type and concentration of enzymatic solution, and temperature, among others. For the enzymatic peeling of citrus, it is important to take into account the ripening stage of the fruits, since variations this parameter modify the concentrations of enzymatic preparation necessary for the peeling process and, probably, the optimum conditions of vacuum. Optimum conditions for enzymatic peeling may not depend on the composition of the albedo in different citrus species. A temperature range between 35 and 40°C, besides being within the optimum range of peeling, would become economically profitable for the industry since a minimum addition of energy is required. For enzymatic peeling the pH range could be wider, between 3.5 and 4.5. The optimum concentration for obtaining a quality product with Peelzym II is 1 ml L, but depends on the composition of the enzymatic solution. The aim of this paper is to update information about the most important parameters implied in enzymatic peeling of citrus fruits, especially factors affecting degradation of the albedo. _____________________________________________________________________________________________________________