Variation in Chilling Susceptibility of Jicama Roots
Jicama (Pachyrhizus erosus) is a traditional root vegetable of Mexico. Important quality chracteristics include a smooth well shaped root, freedom from mechanical damage to the peel, and a crisp white flesh. No chilling injury is observed on roots stored 3 to 4 weeks at 13ºC. At lower storage/transit temperatures, chilling injury of jicama is manifested in various ways: after removing from 0ºC storage, texture is "rubbery" and roots decay rapidly; after 5ºC stroage, external decay and internal graying of the pulp are common; and after 10ºC storage, external quality is typically not affected but severe internal discoloration can occur. All these symptoms of chilling injury are observed on jicama exported and distributed in the United States. A selection of cultivar Agua Dulce grown on the west coast of Mexico had a well developed peel, a starchy flesh, and required 3 weeks at 10ºC to show significant internal browning and 2 weeks at 5ºC to show chill-induced external decay. Another selection of the same cultivar grown in the Bajio area of central Mexico had a crisper more succulent flesh but after <1 week at 10ºC showed significant internal browning and changes in texture.