38 
The production, preparation, and properties of papain for commer- 
cial purposes have been thoroughly studied and discussed by various 
writers, including Kilmer (11, p. 383 395), Pratt (17), Cunliffe 
(4, V- #£)> Macmillan (13), and Chesnut (3). 
PAPAIN 
The collection and preparation of papain as briefly described by 
Higgins (9, p. 17) is as follows : 
There are no difficulties requiring great skill in collecting and preparing 
the juice for market, but care is necessary. Usually only the fruits are 
tapped. These abound in juice, particularly when the tree is young and 
during warm weather after a rain. In the early morning the flow is most 
abundant. Very shallow incisions, not over one-eighth of an inch, are made 
about a half inch apart, lengthwise of the nearly mature green fruits. The 
tapping may be repeated several times at intervals of three or four days. 
Only nonmetallic instruments should be used in tapping or in collecting, for 
the juice acts upon metals and becomes discolored. A bone or ivory blade may 
be used. The flow is free at first and the liquid is caught in porcelain, glass, or 
earthenware vessels. Coagulation soon begins and the mass must be scraped 
from the surface of the fruit. .In most places where the industry is conducted 
labor is cheap, but it would seem that a more convenient and efficient vessel 
could be devised which could be quickly put in place to receive the juice, 
permitting the operator to proceed to the next tree. 
The juice must be dried promptly after it is collected or decomposition begins. 
As the juice flows most freely in the early morning, it is usually collected then 
and dried wholly or in part during the remainder of the day. Sun drying is 
followed to some extent, but artificial means, such as are furnished by a fruit 
drier or one made expressly for the purpose are preferred. In Montserrat 
several driers have been made for the purpose and operated by the companies 
buying the juice from the peasants who gather it. 
One form of drier is about 3 by 3 feet, and 6 feet in length. The sides and 
ends are of brick with an opening at one end for the flue and at the other 
end to admit fuel. The top is open. About a foot below the top a sheet of 
iron is placed and upon this an inch or two of sand to modify and distribute 
the heat arising from the fire beneath. The coagulated juice is, spread upon 
brown linen stretched upon frames which are made to fit the top of the drier. 
The drying must be effected with low temperatures, as great heat destroys the 
ferment. A temperature below 100° F. is preferred by some operators. The 
coagulated material may be placed upon sheets of glass while drying. When 
dry and flaky it may be ground in a coffee mill, preferably while warm, and 
should then be in the form of a white or cream-colored powder, which should 
be placed in bottles and tightly closed. 
In the powdered form or as dried flakes it is exported to America and 
Europe, where it is further refined and sold as a powder or in tablet or other 
form under various trade names as " papoid," " caroid," " papain," and 
" papayotin." 
Little information is available as to yields. Some collectors figure upon a 
yearly production of 1 pound of dried latex per tree. This is probably rather 
a high estimate. The coagulated latex will produce about 25 per cent of its 
weight in dried powder which still contains from 6 to 10 per cent of moisture 
{{11, p. 338)]. About one-sixth of the dried powder is papain. 
SUMMARY 
The papaya, which is believed to be a hybrid of two species of 
Carica indigenous to tropical America, is widely distributed through 
most tropical countries. It is known to have been rather widely dis- 
persed in Pacific countries in the sixteenth century. It was known 
to the Polynesians and probably reached Hawaii in the latter part 
of the eighteenth century. 
