Oct. i8,1915 
Enzyms of Apples 
107 
PREPARATION OF MATERIAL, FOR EXAMINATION 
The first problem was naturally that of securing an extract of the cell 
contents of the apple pulp which would contain the enzyms in active 
form. Since it was not known whether any or all of these enzyms 
would be diffusible through the cell walls (extracellular), a preliminary 
mechanical rupturing of the. cells or rendering of them permeable by 
drying, according to well-known methods of technique in enzytn study, 
was necessary. Several methods were tried, as follows: 
(1) Whole apples were run through a horse-radish grater and the 
resulting pulp pressed in an ordinary laboratory hand press. The 
resulting juice was thick, with small particles of pulp, and attempts 
were made to clarify it by filtration. These were unsuccessful because 
of the clogging of the filter by the pectin bodies of the juice. 
(2) Apples were rasped and pressed as before and the juice allowed 
to stand for some time, during which the suspended solids settled fairly 
well, and the supernatant clear juice was decanted. Precautions against 
enzymic activity during the settling were taken by keeping the settling 
jars in an ice box. 
(3) An attempt was made to secure a dry powder of the apple pulp 
by drying thin slices in a vacuum desiccator over sulphuric acid; but 
the large proportion of sugars and pectin bodies in the tissue made 
this impossible, the slices being gummy and impossible to grind into a 
powder even after six weeks’ exposure in the desiccator. 
(4) Thin slices of apple pulp were treated by the acetone-ether method 
first used by Buchner, Albert, and Rapp (1) in the preparation of 
Dauerhefe , or active dry yeast powder. This process was very satis¬ 
factory, the apple slices, after the treatment and exposure to the air 
overnight, becoming so dry and brittle that they could easily be powdered 
between the fingers and very easily reduced to a fine powder in a mortar. 
Several investigators have reported that the enzymic activity of the 
dry powder so prepared is not less than that of the original tissue, and 
the writer’s observations confirm this. This appears to afford an 
excellent means of preparation of sugary or gummy materials of this 
kind for enzym extractions. 
(5) Apples were peeled and cored, and the flesh cut into small blocks. 
These were then mixed with an equal weight of sharp quartz sand and 
the mixture rubbed gently in a mortar until uniformly disintegrated. 
The mixture was then transferred to a fine silk cloth and pressed gently. 
By this means a limpid juice could be obtained which was nearly free 
from pectin materials, although slightly cloudy with suspended particles 
of pulp. Experience has shown that harsh grinding and severe pressure 
result in diminished activity of the juice, particularly in its oxidase 
activity, but with gentle manipulation, as above, very active juice can 
be obtained. 
