—The properties of a jelly, in respect of its distinct character, are due solely to the fruit from which it is made. Each one of the fruits contains essential oils, ethereal substances, acids, etc., which give to it a distinct character. These bodies are carried with the fruit juice into the 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.
COMPOSITION OF JELLY.
| Se- rial Num- ber. | Descrip- tion of Sample. | Total Solids. | Ash. | Total Acids Ex- pressed as H2SO4. | Pro- teids (N × 6.25). | Sugars. | Polarizations. | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Re- ducing Sugars. | Cane sugar added. | Cane sugar found. | Cane sugar inverted. | Direct at 18° C. | Invert at 18° C. | Invert at 86° C. | |||||||||
| 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 boiling is not continued for any length of time the amount of sugar inverted is less than in the manufacture of jams and preserves where the boiling is continued for a greater length of time.
The quantity of non-crystallizing material in the juices from which the jellies are made, namely, the pectose bodies in fruits, is sufficient in most cases to prevent the crystallization of the cane sugar in the jelly. The jelly is formed by these pectose bodies being present in the juice in sufficient quantities to become semi-solid on cooling after manufacture. The solidifying may take place in a short time or only after several hours. The juice at the time of completion of the boiling is thoroughly sterilized, and in this hot condition should be placed in sterilized vessels and covered before setting away with sterilized parchment paper or a thin film of sterilized paraffine. The covering of the surface will prevent the deposition of the seed of moulds and bacteria which often infect the top layer of jellies or other fruit products prepared in a similar manner whose surface is not properly protected.
Preservatives.
—Since the care which is necessary to prepare a jelly in a thoroughly sterilized condition and to protect the exposed surface so that infection thereof cannot take place is a matter of expense and requires great attention to details, it has been sought to avoid these by the use of chemical preservatives. Salicylic acid and benzoic acid or benzoate of soda have been the principal preservatives employed, and until state and municipal laws introduced a proper inspection or analysis of these products the use of these chemical preservatives was very common. In later years their use has been gradually diminished, owing to the objections on the part of the laws and the public to the presence of these bodies in the finished products. There are, however, still on the market many products which are preserved by salicylic acid, benzoic acid, or benzoate of soda or some similar active agent.
From the above résumé it is seen that the consumer who buys in the open market is not quite certain that he is getting the product for which he pays. This condition of affairs will doubtless pass away with the advent of the proper inspection of fruits which are used in manufacturing on a large scale and a proper supervision of the manufacturing establishments, together with a rigid execution of the national and state food laws. Under such conditions the adulterations will either disappear from the market or be so labeled as to practically inform the purchaser of their character.