An article in Food Chain (7/97) describes the following procedure as an improved method of mango ripening (information taken from Food Digest, Ceylon Institute of Scientific and Industrial Research, 363, Bauddhaloka Mawatha, Colombo 7, Sri Lanka):
“Mangoes are generally harvested when fully matured, but green. The conventional method of ripening in hay has disadvantages like long ripening time, excessive handling, and a high degree of spoilage due to stem-end rot. The spoilage during the ripening period is reported to be as high as 25-30%. In order to improve upon the ripening method, a simple technique has been worked out. It consists of dipping the fully matured, but green mangoes in hot water at 126ºF (52ºC) for 5 minutes, draining and keeping at room temperature until adhering surface water evaporates. Fruits are then packed in ventilated boxes or crates. No hay or other packing material is needed. The ripening generally starts on the 6th day of treatment and is complete on the 12th day. The operation can be made continuous in fruit processing factories where large quantities of mangoes are handled. The hot water treatment is found to reduce the spoilage to the extent of 50% and also helps in uniform ripening of fruits. The color development in the flesh is better than conventionally ripened fruits.”
Now let me add some perspective that will be relevant both for those of you with a single tree and those of you that may be involved in marketing mangoes as an income-generating activity.
‘Maturity’ refers to full development of the fruit, while ‘ripening’ refers to such things as skin color changes from green to yellow, texture changes from hard to soft, and associated chemical changes including the conversion of starch to sugar. The crop is considered mature when the shoulder of the fruit broadens and some fruits on the tree have begun to change color from green to yellow. Prior to this external color change, the fruit is considered mature when the flesh near the seed changes color from white to yellow. Although the fruit will ripen on the tree, commercially it is usually picked when firm, green and mature. As anyone who is familiar with mangoes can attest, fruits picked while immature will ripen, but will remain sour.
Harvesting is done manually. When a mango fruit is mature, the stem will snap easily with a slight pull. If a strong pull is necessary, the fruit is still somewhat immature and should not be harvested. The picker should twist the fruit stem from the twig. Harvesting fruit with approximately 4 inches (10 cm) of stem intact prevents leakage of the milky, resinous sap. If the sap gets on fruit, it will burn the skin of the fruit making black lesions which lead to rotting.
Losses in yield and quality occur when sap damages the fruit (as mentioned above), from anthracnose fruit rot, from the bruising that occurs when fruit drops to the ground, from nonuniform ripening, and when ripening occurs at temperatures above those optimal for ripening (70 to 75ºF; 21 to 24ºC). The hot water treatment (5 minutes at 126ºF/52ºC) has successfully reduced many of these problems. Fruit is picked while green, fewer pickings are required, and greater uniformity in ripening can be achieved. In addition, anthracnose, which can appear as a storage disease of mature fruit causing fruit staining and fruit rot, can be reduced by hot water immersion.