CITRUS PECTIN 
11 
For comparison, three liters of the filtrate was precipitated with 
one and one-half volumes of 95 per cent alcohol in the usual way and 
washed, using the equivalent to 5,500 cc. of 95 per cent alcohol. This, 
gave 16.4 grams of crude pectin. 
Twenty-nine liters of the same filtrate was evaporated in small lots 
on the steam bath below 60° C. in a strong current of air to a paste 
weighing 2,200 grams and containing 25 per cent of total solids. Cal- 
culation showed that about 3,300 cc. of 95 per cent alcohol would be 
required to combine with the water present in the paste and form 
a 60 per cent alcohol mixture. . The following method was used for 
E unification : 1,300 cc. of 95 per cent alcohol containing 5 per cent 
enzol was added to the paste and stirred, and after a short time the 
alcohol was absorbed. The granular mass produced was divided into 
four parts and placed in Erlenmeyer flasks. To each of two of the flasks 
500 cc. of 95 per cent alcohol was added and the whole was heated 
to 60° C. The washings were pressed out and added to the other 
two flasks, with an additional 1,000 cc. of alcohol. These flasks were 
heated to 60° C, and the washings were pressed out and set aside. 
Meanwhile 900 cc. of 60 per cent alcohol was added to one of the 
flasks and heated to 60° C. The washings were pressed out and 
added to the other flasks in rotation and the heating was repeated. 
Then 600 cc. of 60 per cent alcohol was added in rotation and heated. 
By this means only 4,200 cc. of 95 per cent alcohol were required, as 
compared with 5,500 cc. used in the precipitation of about one-tenth 
as much pectin extract. 
The washed material was dried below 70° C. and finally placed in 
the water oven. One hundred and ninety-two grams were obtained. 
The pectins were then ground and examined, with the results shown 
in Table 13. 
Table 13. — Composition of precipitated and washed pectins 
Pectin 
Composition 
Total 
solids 
Ash 
Acid as 
citric 
Pectin 
Original extr a ct 
Precipitated material l 
Washed material 2 
Removed by washing. 
Per cent 
1.97 
88.20 
94.65 
66.00 
Per cent 
0.11 
1.81 
7. 77 
53.00 
Per cent 
0.42 
.40 
8.10 
88.00 
Per cent 
0.48 
85.80 
66.30 
9.00 
1 Quantity required for a good jelly, 0.4 per cent; actual pectin, 0.3 per cent. 
J Quantity required for a good jelly, 0.8 per cent; actual pectin, 0.5 per cent. 
Although the jellying power of the washed sample is less than that 
of the precipitated" sample, owing no doubt to the length of time 
required to evaporate the solution on the steam bath, this pectin 
may be graded as fair. On a large scale, the evaporation could be 
made in a vacuum pan, or better, on a revolving steam drum or some 
similar arrangement, where a little solution is rapidly evaporated 
to a paste. Thus, using a continuous counter-current washing device, 
a minimum quantity of 95 per cent alcohol would be required to 
unite with the water in the paste and form a 60 per cent alcoholic 
solution. The alcohol and also the acid can be recovered from the 
washings. 
