Page:Foods and their adulteration; origin, manufacture, and composition of food products; description of common adulterations, food standards, and national food laws and regulations (IA foodstheiradulte02wile).pdf/417

 finished product and give to it its distinct characteristics. The sugar, of course, in all these products is the same. In the following table are found the data showing the composition of jellies made from different fruits in the Bureau of Chemistry.

. -F1]

COMPOSITION OF JELLY.

Legend: A: B: C: D: E:

F: Reducing Sugars. G: Cane sugar added. H: Cane sugar found. I: Cane sugar inverted.

J: Direct at 18° C. K: Invert at 18° C. L: Invert at 86° C.

_______________________________________________________________________________________________________________________     |          |       |       |       |       |       |       |       |       |       |       |      |  A   |                 |   B   |   C   |   D   |   E   |   F   |   G   |   H   |   I   |   J   |   K   |  L   | ______|________________________|_______|_______|_______|_______|_______|_______|_______|_______|_______|_______|______|     |                        | P.ct. | P.ct. | P.ct. | P.ct. | P.ct. | P.ct. | P.ct. | P.ct. | °V.   |  °V.  | °V.  | 20408 | Apple (fall pippin)   | 59.18 | 0.22  | 0.279 | 0.175 | 20.78 | 51.76 | 33.04 | 36.17 | +24.0 | -20.6 | -1.2 | 20405 | Blackberry            | 59.63 |  .33  |  .475 |  .243 | 12.51 | 54.89 | 44.90 | 18.20 | +47.0 | -20.1 |  0   | 20410 | Crab apple            | 63.28 |  .11  |  .171 |  .137 | 34.93 | 57.61 | 23.68 | 58.88 | +13.0 | -19.0 |  0   | 20405 | Grape (Ives seedling) | 63.66 |  .45  |  .524 |  .175 | 32.29 | 60.29 | 30.52 | 49.33 | +22.3 | -18.9 |  +.2 | 20412 | Huckleberry           | 63.02 |  .28  |  .245 |  .069 | 24.27 | 53.39 | 32.74 | 37.54 | +24.1 | -20.1 |  -.4 | 20435 | Orange (Florida navel) | 68.56 | .30  |  .171 |  .418 |  3.95 | 65.59 | 62.52 |  4.91 | +61.3 | -23.1 |  -.2 | 20437 | Peach                 | 69.98 |  .21  |  .245 |  .175 |  8.75 | 63.70 | 56.59 | 11.16 | +53.4 | -23.0 |  -.6 | 20434 | Pear (Bartlett)       | 69.12 |  .34  |  .181 |  .156 |  6.58 | 63.09 | 58.46 |  7.33 | +52.7 | -26.2 | -1.8 | 20436 | Pineapple             | 80.28 |  .43  |  .328 |  .387 | 22.13 | 72.98 | 56.70 | 28.45 | +50.4 | -26.1 |  0   | 20433 | Pineapple husk        | 76.34 |  .73  |  .352 |  .350 |  7.40 | 70.22 | 65.22 |  7.12 | +63.7 | -24.3 |  -.6 | 20404 | Plum (damson)         | 45.56 |  .68  | 1.127 |  .350 | 19.18 | 38.00 | 22.67 | 40.38 | +17.8 | -12.8 |  0   | 20409 | Plum (wild fox)       | 54.49 |  .40  | 1.029 |  .138 | 24.00 | 48.05 | 25.48 | 46.97 | +16.7 | -17.8 |  0   | 20411 | Plum (wild fox),      |       |       |       |       |       |       |       |       |       |       |      | | boiled down           | 73.01 |  .65  | 1.529 |  .175 | 44.22 | 64.66 | 22.37 | 66.18 |  +7.6 | -22.6 |  -.6 | 20407 | Mixed fruit           | 66.58 |  .21  |  .367 |  .069 | 39.70 | 59.72 | 24.22 | 40.38 | +14.8 | -17.9 | +2.2 | ______|________________________|_______|_______|_______|_______|_______|_______|_______|_______|_______|_______|______|

As is to be expected the chief constituent of these jellies is the sugar which is derived both from the sugar present in the natural juice and from that added in the manufacture. The data show that the quantity of cane sugar inverted varies greatly with the different fruits. Some of the fruit juices appear to have little or no effect whatever in the inversion of sugar. This is particularly true of the orange, the pear, and the jelly made from the husks of pineapples.

Manufacture of Jellies.—In the manufacture of jellies the fruit juices are separated from the pulpy mass of the fruit, and these alone are used in the process. The most common method of procedure is to boil the fruit with more or less water until the juices are more or less separated and then to remove them by straining or pressure. The fruits are heated for this purpose with sufficient water to prevent scorching until they are thoroughly softened and then reduced to a pulp. The best jellies are made from juices which are obtained by simply allowing the pulpy mass to drain through cloth. The juices thus obtained are clear and free of any suspended matter. When pressure is used the juices are less clear and contain more or less suspended solid matter. In the preparation of jellies approximately equal portions of pure cane sugar and the strained juices are used, and the mixture is heated to the boiling point. It is evident that in the manufacture of jelly where