4 BULLETIN 1323, U. S. DEPARTMENT OF AGRICULTURE 
TaBLE 1.—Composition of lemon pectin extracts before and after dialysis in 
collodion sacs 
Composition 
sh Total Acid N 
ot cid as : onpec- 
solids Ash citrie | Pectin | tin solids 
mt | Per cent | Per cent 
3. 47 
Before dialysis 0. 30 0. 73 
After dialysis: 
Sae Logi ae ge. oe eR Rae eee eae ati OOM Sites 46 ~ol 
S80 2255 eae Ce See eee BO Sig eee ee 81 OSs) teers ead ZoD . 46 
Sees 4.26 fo dees Pe ee Sots SC SE ee A ee eee , are Shs ot Bae 
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 liters) 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 Nor 
Total Acid as . : 
p Ash Anas Pectin pectin 
solids citric solids 
Lot 1: Per cent | Per cent | Per cent | Per cent | Per cent 
Before:diahysis. 3.4222 siesta hence 0. 38 0. 27 0. 97 5. 52 
IATGET CIAL WSIS 2 2). ee Sone fae pat se ee es ee 1. 83 . 09 . 06 . 61 1. 22 
Lot 2: 
Beforeidialysis.. 2.42: $24 ates 2 Ae eae ee ee 2.53 .19 «15, ah 1.76 
] 
Aiter dialysis_.; 222.2. 0 =22.* See eee eee | .o7 13 . 05 - 51 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 cei htes 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 
neatly all of the bitter principles. About half of the pectin dissolved, 
owever. 
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. 
