4 BULLETIN 1323, U. S. DEPARTMENT OF AGRICULTURE 
Table 1. — Composition of lemon pectin extracts before and after dialysis in 
collodion sacs 
£ 
oia position 
Pectin 
Total 
solids 
Ash 
Acid as 
citric 
Pectin 
Nonpee- 
tin solids 
Per cent 
4.20 
.77 
.81 
Per cent 
0.41 
.09 
.04 
Per cent 
0.30 
Per cent 
0.73 
.46 
.35 
.32 
Per cent 
3.47 
After dialysis: 
Sac 1 
.31 
Sac 2 „ 
.46 
Sac 3 
"1 ""IT 
Two lots of orange pectin extract were dialyzed in a small osmogene 
designed by Poore (41), using tap water heated to 75° C. Lot 1 
(38 Titers) was dialyzed for 168 hours, although the extract and tap 
water were in motion for only 45 hours. Lot 2 (72 liters) was 
dialyzed for 190 hours, with the extract and water in motion for 47 
hours. The results are shown in Table 2. 
Table 2. 
-Composition of orange pectin extracts before and after dialysis in 
osmogene 
Composition 
Pectin 
Total 
solids 
Ash 
Acid as 
citric 
Pectin 
Non- 
pectin 
solids 
Lotl: 
Per cent 
6.49 
1.83 
2.53 
1.57 
Per cent 
0.38 
.09 
.19 
.13 
Per cent 
0.27 
.06 
.15 
.05 
Per cent 
0.97 
.61 
.77 
.51 
Per cent 
5.52 
After dialysis - 
1.22 
Lot 2: 
1.76 
1.06 
Jellies made from the concentrated dialyzed extracts were poor 
in taste and appearance. The experiments showed that until a 
membrane less permeable to pectin and with a greater speed of 
dialysis for the other constituents is produced, the dialysis method 
will not be satisfactory. It is possible, however, that the electro- 
osmotic purification method of Schwerin (U. S. Patent 1,235,064), 
as applied to glue, gelatin, and other colloidal substances, would be 
practicable. 
By agitating several 110-kilogram lots of finely-ground residue in 
running water under various conditions, it was possible to remove 
nearly all of the bitter principles. About half of the pectin dissolved, 
however. 
If ethyl alcohol, one of the cheapest and best organic precipitants 
of pectin, is used, the pectin extract must be concentrated as far as 
practicable in order to avoid using too much. Powdered pectin 
was treated with alcohol of different strengths at room temperature 
for two days, and at 60° C. for two hours. At least 60 per cent 
alcohol by volume, or 54 per cent by weight, was necessary to pre- 
cipitate all of the pectin from solution. 
