Question
Upon reading the postharvest report for mangos, I noted that there is no mention of hard sunken areas around the shoulders. I had previously been told this type of injury was from the hot water treatment: the cells die and the tissue collapses, hollow cavities become discolored and dry. Is internal flesh breakdown (stem-end cavity) related to the hot water treatment, and more prevalent on tree ripened fruit, or is it unrelated? Is the defect present at time of packing, or does it develop in transit? Any information you have on this defect would be greatly appreciated. (R.M.C.)
Answer
Damage from heat treatments in mango can result in a range of symptoms including those shown in the photographs that you sent. Ripe fruit can be more sensitive to heat damage than mature-green fruit of similar size when subjected to the same heat treatment. High temperature accelerates respiration rate and associated carbon dioxide accumulation and oxygen depletion in certain regions within the fruit. High carbon dioxide levels (>10%) and low oxygen levels (<2%) can kill the cells, which dry out and cavities form in their place. If the affected regions are just below the fruit shoulders, depressions will result around the stem. The heat damage begins immediately after exceeding the time-temperature combination that is tolerated by the fruit (before packing), but subsequent symptom development continues during transportation and distribution. Unfortunately, the consumer is the one who gets to see the fully developed symptoms and is disappointed in the mango quality. I have noted gray flesh discoloration and/or hollow cavities in some fruit of every lot of mangos that I have purchased at retail markets since March, 2003. I think that mango shippers need to improve their management of heat treatments to reduce heat damage and /or develop irradiation facilities to use ionizing radiation as a quarantine treatment instead of heat treatments.
-Adel Kader