Papain is the dried purified latex of the unripe fruit of paw-paw, Carica papaya Linn., a small soft tree of the family Caricaceae.
The Paw-paw tree is indigenous to tropical America, but is now grown abundantly in most tropical countries of the world including Bangladesh and Nigeria.
Macroscopical and microscopical characters:
Crude papain (the dried latex) occurs in coagulated off-white mass. Purified papain, obtained by first dissolving the coagulated latex in water and then precipitating with alcohol, occurs as a white or creamy white amorphous powder. It is odourless, but possesses a somewhat bitter taste.
Papain is a mixture of several enzymes which include one or more proteolytic enzymes, a renin-like coagulating enzyme, an amylolytic enzyme, a clotting enzyme and a weak fat hydrolysing enzyme.
Papain is used as a digestant for proteins and as a mucosolvent. It is extensively used as a meat tenderiser.