Methods of collection and extraction
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Papain is obtained by cutting the skin of the unripe but almost mature papaya and then collecting and drying the latex which flows from the cuts. Tapping of the fruit should start early in the morning and finish by mid-late morning (ie during periods of high humidity). At low humidity the flow of latex is low.
Two or three vertical cuts (except the first cut, see below) 1-2mm deep are then made, meeting at the base of the fruit. The incisions are made using a stainless steel razor blade set into a piece of rubber attached to a long stick. The blade should not protrude more than about 2mm as cuts deeper than 2mm risk juices and starch from the fruit pulp mixing with the latex which lowers the quality.
Fruits should be tapped at intervals of about 4-7 days and for the first tapping it is usually sufficient to make only one cut. On subsequent tappings the two or three cuts are spaced between earlier ones (as explained above).
After about 4-6 minutes the flow of latex ceases. A dish is used to collect the latex and the latex is then scraped into a polythene lined box with a close fitting lid; such a box should be stored in the shade. The use of a close fitting lid and keeping the box in the shade are both important because they reduce the reactions which cause the loss of enzyme activity. Foreign matter such as dirt and insects in the latex should be avoided. Latex adhering to the fruit should be carefully scraped off and transferred to the collecting box. However, dried latex should not be mixed with fresh latex as this lowers the quality.
When handling fresh latex, care should be taken to ensure that it does not come into contact with skin as it will cause burning. Neither should it come into contact with heavy metals such as iron, copper or brass as this causes discolouration and loss of activity. Pots, knives and spoons should not be used unless they are made from plastic or stainless steel. Fresh latex does not keep well and should be dried to below 5% moisture (when it will have a dry and crumbly texture) as soon as possible.
After two or three months the fruits are ripe and should be removed from the tree. The ripe fruits are edible but have very little sale value because of their scarred appearance. However, the skin of the green ripe papaya does contain about 10% pectin (dry weight) and the fruits could be processed to extract this.
https://www.appropedia.org/Papain_Produc...ion_Brief)
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