CITRUS PECTIN 
15 
Table 18. — Effect of variation of 'pectin, acid, and sucrose on consistency of jelly 
Sample 
No. 
Pectin 
Citric 
acid 
Total 
sugar as 
sucrose 
Consistency 
Sample 
No. 
Pectin 
Citric 
acid 
Total 
sugar as 
sucrose 
Consistency 
Per cent 
Per cent Per cent 
Per cent Per cent 
Per cent 
1 
0.26 
0.82 
39.1 
Sirup. 
14 
0.60 
1.07 
40.0 | Sirup. 
2 
.26 
.82 
43.0 
Barely jellied. 
15 
.60 
1.07 
43. Good jelly. 
3 
.26 
.82 
47.8 
Fair jelly. 
16 
.CO 
1.51 
34.8 Sirup. 
4 
.26 
1.07 
39.1 
Sirup. 
17 
.60 
1.51 
40. 1 Good jelly. 
5 
.26 
1.07 
45.8 
Fair jelly. 
18 
.77 
.82 
39.1 
Barely jellied. 
6 
.26 
1.51 
47.8 
Do. 
19 
.77 
1.07 
39.1 
Good jelly. 
7 
.43 
.82 
39.1 
Sirup. 
20 
.77 
1.51 
35.5 
Sirup. 
Good jelly. 
8 
.43 
.82 
43.0 
Good jelly. 
21 
.93 
.82 
39.1 
9 
.43 
1.07 
40.0 
Sirup. 
22 
.93 
1.07 
35.5 
Sirup. 
10 
.43 
1.07 
43.0 
Good jelly. 
23 
.93 
1.51 
34.8 
Do. 
11 
.43 
1.51 
39.1 
Sirup. 
24 
1.11 
1.07 
32.6 
Do. 
12 
.60 
■ .82 
38.3 
Do. 
25 
1.11 
1.13 
36.4 
Good jelly. 
13 
.60 
.82 
43.0 
Good jelly. 
26 
1.11 
1.51 
33.3 
Sirup. 
In making jellies with orange juice much less inversion of the 
sucrose was obtained than when working under like conditions with 
equivalent quantities of acid and pectin solutions, owing to the 
presence in the juice of inorganic salts, which, as noted by Browne (8), 
will diminish the inversion velocity of the acid. A sample of orange 
jelly stock containing 0.27 per cent of ash was jellied by the standard 
test (boiling for 1 minute) and also by boiling for 5, 10, and 15 minutes. 
The pectin was then precipitated from some of the jelly stock and 
redissolved in enough distilled water to give the original concentra- 
tion of pectin, and the jelly test was made. The pectin-free stock 
and a solution of the ash after being made up to their original con- 
centration were then given the standard jelly test. The results are 
shown in Table 19. 
Table 19. — Effect of mineral matter of orange juice on inversion of sucrose 
Sample 
No. 
Material 
Citric 
acid 
Invert 
sugar 
1 
Original stock solution: 
Per cent 
0.52 
.55 
.53 
.54 
.46 
.48 
.51 
.54 
.43 
.49 
Per cent 
10.87 
2 
19.02 
3 
25.58 
4 
35.87 
5 
Precipitated pectin solu;ion: 
32.61 
6 
50.27 
7 
Stock solution freed of pectin: 
11.41 
8 
18.66 
9 
Solution of ash: 
10.33 
10 
19.02 
HOW TO MAKE CITRUS JELLIES AND MARMALADES 
As a result of the work here reported, a rapid and dependable 
method for making orange jellies and marmalades on a large scale, 
which standardizes the product as to color and consistency, has 
been developed. This method is described in Department of Agri- 
culture Circular 232, ''By-products from citrus fruits." 
