Curing

• It is the process of toughening and self-healing of bruises and skinned areas in root and tuber crops; and the rapid closing of the neck of bulb crops under favorable conditions is known as curing.
• Another term is wound healing. Lignification of citrus cells with minor injuries is also termed curing.
• Some authors consider curing of onions as the additional process of development of better skin color by exposure to high temperature.
• Curing is accomplished by exposing the commodity to the temperature, which is slightly higher than the growing temperature.
• Curing provides protective layer in the wound or surface.
• Curing is the most important operation if potatoes are to be stored for longer duration.
• Accumulation of anti-fungal substances has also been reported in cured wound.
• Curing minimizes water loss and microbial attack.

Process of curing

• The first step is the deposition of suberin in the cut surface in tubers and lignification in the surface of citrus. This process occurs within 24 hours in potato and sweet potatoes.
• In potato and sweet potato the cells below the suberized layer becomes meristematic and gives rise to periderm, the secondary protective tissue in the roots and tubers. The periderm layer consists 6-8 layers of cork cells and cork cambium. Often the dense network of cork cells is called phellem. This process starts within 3 days in sweet potato and completes within one or two weeks.
• Sweet potato, potatoes, taro, onion, garlic and similar crops are cured priors to storage or marketing. Injured or brushed surfaces are allowed to heal by holding for a few days at ambient temperature. Periderm formation during healing is favored by high temperature and high relative humidity.