Pineapple, Ananas comosus / Bromeliaceae
Postharvest Atmosphere Management
Pineapples are very fragile fruit and sensitive to sudden changes of temperature. It is possible to store them for few days in a fresh and dry place, although it must never be kept in the fridge, since temperatures below 7ºC injure the fruit. Once cut and peeled it can be stored in the fridge covered with plastic, trying to consume it as soon as possible.
If pineapples are subject to ethylene exposure, the degreening of the skin will be faster, not affecting the internal quality. The degreening means the loss of chlorophyll. Pineapples must be harvested when they are sufficiently mature to be consumed, since they do not continue maturation after harvesting.
Controlled atmospheres delay senescence and reduce the rate of respiration. The optimal proportions are 3-5% of oxygen and 5-8% of carbon dioxide. The potential post-harvest life varies from 2 to 4 weeks in air, and between 4 and 6 weeks in controlled atmospheres at 10ºC, depending on the degree of maturation and the cultivar.
Distribution
The same environmental conditions for storage are the optimal for transport and distribution.
Postharvest Problems
After the harvesting, pineapples may undergo some problems caused by chilling injuries and pathogens.
Chilling imjuries
The exposure at temperatures below 7ºC causes chilling injuries. Mature fruit is more susceptible to suffer these damages than the green one. The symptoms include a duller green colour, soft and wet flesh, a darker colour of the surface, and higher susceptibility to damages caused by falls and hits.
Damages caused by pathogens
- Dark rot: caused by Thielaviopsis paradoxa. It begins in the stem and spreads to the flesh. The affected area lowers with a slight pressure and it darkens.
- Fermentation caused by yeast: Caused by Saccharomyces spp, it is generally associated to an excessive maturation of the fruit. The yeast gets inside the fruit through the wounds. The fruit’s flesh softens and turns into a yellow colour. It is also easily broken.