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Witloof chicory, Cichorium intybus / Compositae
Postharvest Atmosphere Management
Witloof chicory
In order to maintain the quality of witloof chicories at home, we must not expose them to the light for a long time, since the leaves decay and acquire a greenish colour. Besides, their bitter taste sharpens and they loose some properties. They can be kept from 5 to 7 days in the fridge, inside a perforated plastic bag, although it is better to consume them right after the purchase They are not suitable to be frozen.

Depending on the period of the year, chicories have temperatures that usually range between 16 and 20ºC after the preparation. For that reason it is necessary to pre-cool them, trying to obtain in short time temperatures near 0ºC. The most suitable methods are vacuum and humid air pre-cooling. With the former, the already packaged chicories reach temperatures between 0 and 2ºC in 20 minutes. With humid air, temperatures are between 16 and 3ºC in 4 hours if using flow rates of 2.7 m3/kg/h, and in 10 hours for 1.9 m3/kg/h flow rates.

Hydro-cooling also allows to reach similar temperatures by means of vacuuming. But the keeping quality is worse, since the leaves store some water.

Storage at 2ºC enables losses of 10% of the produce, whereas at 10ºC these rise up to 30%. Good storage conditions call for protection against dehydration; thus, relative moisture must be over 95%. Plastic covers help to prevent dehydration.

Modified atmospheres with 4-5% of carbon dioxide and 3-4% of oxygen have been proved to be the optimal for storage at temperatures of 0ºC and a rank between 0 and 5ºC. We can take advantage of the positive effects of carbon dioxide by means of using plastic covers with a permeability such as to enable a slight enrichment of the atmosphere with this gas, but without reaching the potentially harmful level of 3%. However, this system is not used in trade.
Distribution
Transport must be cooled at temperature around 0ºC not exceeding 10ºC, with high levels of relative moisture. This is particularly important if they are transported in bulk, without plastic.

The loss of quality implied in the greening of the vegetable must be avoided by means of protecting the product from light in the stages previous to sale.
Postharvest Problems
The metabolic activity of chicories is very high, reason why they have a short post-harvest life, a month at the most.

After the harvesting a set of changes may result in the deterioration of their quality. The most frequent are: loss of water, greening, opening of the heart, parasitic diseases and development of red or brown tones on the leaves.

Dehydration
The loss of water brings about the loss of turgescence, symptoms of blight and weight loss.

Greening
Greening is usually accentuated in well-illuminated shelves. Greening is caused by exposure to light.

Opening of the heart
The opening of the heart is caused by the continuation of the growth process, leading to the loss of commercial value.

Parasitic diseases
Among them most important alterations we find soft rot, caused by bacteria affecting the outer leaves and soon occurring also in the heart. The bacteria belong to the genus Erwinia, Pseudomonas and Xanthomonas. There can also appear some rottings caused by the fungi Sclerotinia sclerotiorum and Botrytis cinerea.

Reddish or brown tones
These alterations occur on the leaves or the cut tips. They are due to the late manifestation of these symptoms or the oxidation of substances inside the cell in the areas that have been damaged during handling.
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