LIFE

01 AN 82

MUS

VOL. III.

The Detection of Adulteration in Food.

BY C. M. VORCE, F. R. M. S. V.-RED-PEPPER AND TURMERIC. Next to black-pepper, red-pepper, usually called Cayenne pepper, seems to naturally deserve attention. This substance, which, from its name, many people suppose to be derived from a variety of the same plant which furnishes black-pepper, is the ground pod and seeds of a plant almost exactly similar in microscopical characteristics to the common, large red-pepper of our gardens, so extensively used for pickling. The commercial Cayenne pepper is chiefly prepared from the pods of the Capsicum annuum, although some other varieties of capsicum are occasionally used.

Pursuing with this, the plan adopted with other substances, we procure some of the unground, dry pods which we find to be thin, bright-red, conical pods with a slight oily feeling, divided lengthwise by a thin septum, usually into two, occasionally three, compartments, in each of which is a double row of flat, hard seeds overlapping each other like shingles. The pod of an especially fine sample of imported capsicum is shown in section, natural size, in fig. 1, plate I, and the seeds, also natural size, in fig. 2 a. The pod and seeds are extremely pungent and stinging to the tongue and the slightest touch will leave a taste for several minutes. The outside of the pod is smooth and shining to the eye, but the inner surface is covered with minute, short ridges, which instantly bring to mind the appearance of a very highly magni

Fig. 3.

Fig. 5

Fig 7.

Fig. 9.

Fig. 13.

Fig. 12.

Fig. 14.

b

Fig. 17

Fig. 21.

Fig. 24.

it in water by one-inch objective, the ridges of the inner surface are seen to be hollow, like blisters, of a shining yellow color, and only attached to the substance of the pod at their edges; some are loosely filled with a colorless matter having the appearance of empty, collapsed pulp-cells, while some are quite empty (fig. 13 a). A clear, thin membrane lines the pulp-cells under the raised inner ridges (fig. 13 6). The substance of the pod is composed of small pulpcells, originally oblong or roundish, now compressed by drying, and full of a yellowish, finely granular cellcontents having an oily appearance. The pod is from eight to ten or more cells in thickness, the layer of cells on the outer surface being quite distinct from the interior layers. pulp-cells adjoining the space under each of the raised ridges of the inner surface of the pod are of a deeper, somewhat reddish color, for a depth of from three to seven cells, as indicated by dotted lines in fig. 13, where the pulp-cells are omitted from part

The

Fig. 16. Transverse section of seed, untreated, x 73.

Fig. 17. Surface of seed, showing shape of pits in the surface, x 250.

Fig. 18. Sections of shell and seed, x 250: a, treated with potash; b, with nitric acid. Fig. 19. Thin membrane enveloping cotyledon of seed, x 250.

Fig. 20. Section of cotyledon of seed treated with potash, x 250, showing also starch of the seed, untreated, as seen by 1-inch, 4-inch and-inch objectives.

Fig. 21. Yellow starch-grains of turmeric, X 250.

Fig. 22. Light-colored starch (a) and cells of root-bark (b) of same, x 152.

Fig. 23. Spiral vessels of turmeric-root, X 250.

Fig. 24. Starch: a, of turmeric (?); b, of rice; c, of wheat found in ground turmeric, x 250.

Fig. 25. Scales of vegetable substance found in ground turmeric, x 152.

Fig. 26. Cellular tissue of turmeric with starch-grains, x 152.

Fig. 27. A, the yellow starch (Fig. 21), b, the white starch (Fig. 24 a) of turmeric treated with potash, x 152.

Fig. 28. Masses of earthy adulterants softened by water, × 250.

of the figure. The same drops of oil (fig. 6) are plentiful in the water surrounding the section, and the water is very pungent to the taste.

In a portion of the pod that has been macerated one night in nitric acid, the pulp-cells (fig. 12 b) are more swollen than those acted on by potash; the color is nearly all extracted, and the cells of the outer surface now show the separate layers of the cell-wall, the central, thickened layer being very distinct, and the thin, slightly wrinkled, inner layer, or primordial utricle, less distinct but plainly visible (fig. 11). A section

of the outer skin of the pod, now easily separated from the pulp, shows the thickened framework of the cells cut across, and having a clear glassy appearance and a light-yellow color, in section, while the surface appears finely punctate (fig. 14). No cellcontents are present and no trace of the outer cell-wall forming the surface of the pod can be seen in the section, although it is readily seen in surface-view. A great number of sections were made and examined in the effort to discern the reason of this disappearance, but without success. The inner surface of the pod, after maceration in acid, presents an exceedingly beautiful appearance; being somewhat swollen, the crookedness of the cell-walls is thereby lessened, the secondary layer is very distinct, and the primordial utricle is festooned in loops and has exactly the appearance of being tied back at close intervals to the thick cell-wall, while the cell-contents are shrunken to a small globule in the centre of the enlarged cell (fig. 15). Under the microscope the inner layer of ridges, when untreated, appears of a clear, horn-like consistence, and to the fingers the pod seems tough and leathery, with a slight oily feel, and one instinctively wonders how it is practicable to grind it to a fine powder.

Passing now to the examination of the seed, which constitutes the greater bulk of this variety of capsicum

fruit, we find the seed covered with shallow pits of sinuous shape, separated by sharp-edged serpentine ridges shown in outline in fig. 17. When softened by maceration in potash, the seed appears to the eye as in fig. 2 b, and if macerated in nitric acid is still softer and more transparent, appearing as in fig. 2 c, in which the coiled radicle is visible to the eye by transmitted light. A transverse section across the seed, about its middle, examined in water by a one-inch objective appears like fig. 16. The hard seed-coat is of considerable thickness with the outer surface serrated and separated from the cotyledon by a thin membrane. The cells of the cotyledon are small, angular, and filled with granular matter; the transverse sections of the radicle are darker-colored, because composed of smaller cells with cell-contents more green. On squeezing out of one of the cut seeds the enclsoed cotyledon and crushing it on a slip in water, it is found to be enclosed in a thin, square-celled, hyaline membrane (fig. 19). The crushing of the seed sets free a cloud of minute, white, spherical starch-granules, which render the water cloudy, and are barely visible with an inch objective; by the quarter-inch objective they are seen distinctly, but not so as to reveal any hilum. These starch-grains are shown in the upper part of fig. 20, as they appear by half and by quarter-inch objectives, and three of the granules as seen by a one-tenth-inch homogenousimmersion lens, are shown at the right of fig. 20.

The outer seed-coat of a macerated seed, viewed from the outside, shows the outlines of the cells to correspond with the pits of the surface, as in fig. 17, in which the lines represent the sharp edges of the ridges separating the pits, which are very much deeper than in the dry seed. A section of the macerated seed-coat is shown in fig. 18. The membrane lining the shell of the seed, which is hyaline in its natural state, becomes

The chief adulterant, beside starch, is ground turmeric, the color of which is very near that of capsicum and which also has some degree of acridity. To determine the structure of turmeric, we should require a piece of the root in its uatural state, but this is by no means easy to obtain. I have visited many druggists at home, and also sent to other cities for it without finding it, and one druggist of many years' experience, whose specialty is botanical drugs, told me he had never seen the root except in powder, and volunteered the information that but little of the powder sold as ground turmeric is really curcuma at all. But having collected samples of socalled ground turmeric from a number of different sources, and finding them all to agree in certain microscopical characteristics, as well as in color, taste and smell, I conclude that there is really a good deal of powdered curcuma-root in the market after all. The figures 21 to 26 inclusive, show structures common to all the samples of turmeric examined, and omitting mention for the present, of structures found only in some of the samples, these structures (figs. 21 to 26), will be considered as representing genuine turmeric.

The color of turmeric is instantly extracted by alcohol while that of capsicum is not, hence it may be detected by this means without the microscope; on dropping a little suspected cayenne into one of two small vials of alcohol placed side by side. before a light if any turmeric is present a yellow tint will be instantly manifest, its color depending on the amount of turmeric. The presence of earthy or metallic substances can be discovered by decantation in testtubes. Starch is detected by icdine, or still better by the microscope. The starch of turmeric is large and of a clear, transparent, yellow color, in rounded, somewhat irregular grains, each of which occupies its own cell in the tissue of the root (fig. 26); but in ground samples it is mostly free or in