papaya is an amazingly rich source of the proteolytic enzymes. These are the chemicals that enable the digestion of protein. Papain, which is the most important of these enzymes in the papaya, is extracted and dried as a powder for use to aid the digestion, and it is often used as a meat tenderizer, the enzyme partially breaking down the meat fibres - digesting them in fact.
Many experts have claimed rejuvenating properties for papaya, especially for the control of premature aging.