Papain is an active enzyme present in the latex or milky secretion of papaya plants and immature fruits. Half to three-fourth matured fruits (about 70 to 100 days from fruit set) are preferred for papain extraction. Tapping of fruits can be done early in the morning by giving longitudinal skin-depth incisions (0.3cm) on the surface of the fruits from the stalk end to tip. Stainless steel blades or knives or bamboo splinters are used for incising papaya fruits. The milky latex is collected in arecanut spathes or aluminium or glass vessels.
The incisions are repeated in two or three subsequent occasions at 3 to 4 days intervals. The latex collected in this way is dried in the sun or in an artificial drier at 50-55°C. A small quantity of potassium metabisulphite is added to the liquid latex to extend the storage life of papain. The dried latex can be stored in airtight polythene or glass containers for a period of six months. Tapped fruits are equally tasty as untapped fruits, although impaired in appearance.