Kohlrabi, Brassica oleracea var. gongylodes / Cruciferae (Brassicaceae)
Postharvest Atmosphere Management
Kohlrabis cannot be conserved for long time. The suitable conditions are 0-1ºC and 90-95% humidity. If the leaves are removed, they are preserved for longer time, even for 3 months.
In the case of early or summer harvested kohlrabis, under high temperatures, the precooling operation is important. Ice or water are used for this prupose, although vacuum cooling is also recommended for kohlrabis with leaves.
The root must be removed before the storage. The suitable conditions are 0-1ºC and a relative humidity between 90 and 95%. In this way, kohlrabis are conserved up to 4 weeks.
In order to enlarge the preservation period, controlled atmospheres are used. Maintaining a 3% oxygen concentration and 5% carbon dioxide, defoliate kohlrabis may last up to 4 months.
Distribution
During transport and distribution it is advisable to maintain high humidity levels in order to avoid the pieces drying. The temperature for short trips will not exceed 20ºC. For longer distances it will be lower.
For transports up to 6 days it is recommended not to exceed 20ºC. Relative humidity must be high to prevent wrinkles in the vegetable. During distribution, the aeration must be considered.
Postharvest Problems
During the storage, kohlrabis may develop damages due to diseases like humid bacterial rot and black rot. They can also suffer quality loss due to dehydration or hardening.
Although kohlrabis cannot be stored for long periods, there can appear several problems, such as diseases.
Among the most important are the humid bacterial rot and the black rot. The former is characterized by the presence of soft areas that exude liquid and in general give off an unpleasant bitter scent. The black rot is caused by the Xanthomonas campestris bacterium. It bacterium appears in the field, and when these pieces arrive at the store room they are infected by other pathogens through the affected zones.
There are several agents that cause quality loss of the product, such as dehydration, caused by an insufficient relative humidity, and lignification, that produces the hardening of the piece due to the excessive fiber formation.