CHAPTER III
HOW TO DETECT ADULTERATIONS IN SPICES—THEIR FORMATION AND ANALYSIS
AS far as its practical use to the merchant or consumer of spices is concerned, it would be as well, perhaps, if this chapter remained unwritten, and yet this treatise would be far from complete without it, as much of that which is herein contained is of the utmost importance, could it be put into practice.
In this chapter I attempt to give ways to detect adulterations, but the lamentable fact is that the general merchants have neither the time nor the facilities at hand to discover the foreign substance.
There are two principal ways of detecting adulterations in spices, which depend upon the difference in the structure of the cells between the adulterants and the true spice to which they are added, and also on their proximate composition. The former difference is recognized by the mechanical separation and by the use of the microscope, and the latter by chemical analysis. The adulterations found in spices may be classed in four grades:
_First._ Integuments of grains of seeds, such as bran of wheat and buckwheat, hulls of mustard seed, flax seed, etc.
_Second._ Farinaceous substances of low price, as spice damaged in transportation or by long storage, middlings, corn meal, and stale ship bread.
_Third._ Leguminous seeds, as peas and beans, which contribute largely to the profit of the mixer.
_Fourth._ Various articles chosen with reference to their suitableness to bring up the mixtures, as nearly as possible, to the required standard color of the genuine article; various shades from light colors to dark brown may be obtained by skillful roasting of the farinaceous and leguminous substances, and a little tumeric goes a long way to give a rich yellow color to real mustard made from pale counterfeit of wheat flour and terra-alba, or the defective paleness of artificial black pepper is brought to the desired tone by judicious sifting in of a finely pulverized charcoal.
From what has been said of the different foreign substances used for adulterations of spices and condiments, the necessity of knowing the structure and formation of the molecules of both principal and foreign elements which constitute the principal tissues of the particular plant-parts used for the adulterations is apparent, while in the chemical examination the principle of proximate analysis must be understood and applied.
It is also necessary that the analyst should be thoroughly acquainted with the application of the microscope, to determine the cellular structure, to make determinations of proximate principles in the substances under examination, since a mechanical separation by the microscope is more expeditious and is more at the command of the majority of persons searching for adulterations. For a mechanical analysis of food separations, a powerful microscope of good workmanship is required. It is better if it is supplied with a substance condenser and Nical prisms for the use of polarized light. Objectives of an inch and half inch, and, for some starches, one-fifth inch, equivalent focus, are sufficient. One eye-piece of medium depth, one-fourth to one-sixth, adjusted at 160 degrees is enough, with plenty of good light. The analyst should also have plenty of sieves of 40 to 60 meshes to the inch to be used for separation, which will furnish means of detecting adulterants and selecting particles for investigation, and will often reveal the presence of foreign material without further examination, since many adulterants are not ground so fine as the spices to which they are added, and by passing the mixtures through the sieves the coarser particles remaining will be either recognized at once by an unaided educated eye or with a pocket lens.
In this way, tumeric is readily separated from mustard and yellow corn meal; mustard hulls and cayenne, from low-grade pepper. Where a pocket lens is insufficient, the higher power of the microscope is confirmatory. It is also desirable to be provided with a dissecting microscope for selecting particles for examination from large masses of ground spice, and for this a large Zeiss stand, made for that purpose, is best, but simpler forms, or even a hand lens, will answer the purpose. For smaller apparatus, a few beakers, watch crystals, stirring rods, and specimen tubes, with bottles for reagents, will be sufficient, in addition to the ordinary glass slides and covers for glasses. The reagents required for chemical analysis (if no great amount is used) are as follows:
Strong alcohol, Ammonia, Chloral-hydrate solution—8 parts to 5 of water, Glycerine, Iodine solution—water 15 parts, iodide of potash 20 parts, iodine 5 parts; water distilled.
Balsam in benzol and glycerine jelly are desirable for mounting media, and some wax sheets will be needed for making cells. In addition, the analyst should supply himself with specimens of whole spices, starches, and known adulterants, which may be used to become acquainted with the forms and appearances to be expected; it is easier to begin one’s study in this way on sections prepared with the knife, and afterwards the powdered substance may be taken up.
To study the physiological structure in the spices and their adulterants is quite difficult, as the vegetable tissues which make up the structure of the spices and the materials of a vegetable origin which are added as adulterations consist of cells of different forms and thickness; those which are most prominent and common are the parenchyma, the sclerenchyma fibrous tissue, and the fibro-vascular bundles. Spiral and dotted vessels are also common in several of the adulterants, and in the epidermis are other forms of tissue which it is necessary to be well acquainted with, though not physiologically. The parenchyma is the most abundant tissue in all material of vegetable origin, making up the largest proportion of the main part of the plant. It is composed of thin wall cells which may be recognized in the potato and in the interior of the stems of maize. In the latter plant, also, the fibro-vascular system is well exemplified, running as scattered bundles between the nodes or joints. Fibrous tissue consists of elongated thick-walled cells of fibers which are very common in the vegetable kingdom and are well illustrated in flax, but they are not so commonly used for adulterating purposes. They are optically active, and in the shorter forms they somewhat resemble the cells next described. They are seen in one of the coats of buckwheat hulls and in the outer husks of the cocoanut.
The sclerenchyma is found in the shells of many nuts and in one or two of the spices, the cells being known as stone cells, from the great thickening of their walls. To them is due the hardness of the shell of the cocoanut, the pits of the olive, etc. (See Fig. 1.) Spiral and dotted vessels are common in woody tissue and are readily recognized. All these forms an analyst should make himself familiar with.
In pepper and mustard the parenchyma cells are prominent in the interior of the berry, while those constituting the outer coats are indistinct in the pepper, because of their deep color; but in the mustard are characteristics of this particular species. In fact, in many of the spices, and especially those which are seeds, the forms of the epidermal cells are very striking, and, if no attempt is made to classify them their peculiarities must be carefully noted, as the recognition of the presence of foreign husky matter depends upon a knowledge of the normal appearance in any spice.
The fibro-vascular bundles are most prominent in ginger and in the barks, while in the powdered spices they are found as stringy particles. The sclerenchyma, or stone cells, as shown in Fig. 1, are common in the adulterant, especially in cocoanut shells, where may also be seen numerous spiral cells, and in the exterior coats of fibrous tissue. As to aids to distinguish these structures, the following peculiarities may be cited:
The stone cells and fibrous tissue are optically active, and are, therefore, readily detected with polarized light, shining out in the dark field of the microscope as silver-white or yellowish bodies.
The fibro-vascular bundles are stained deep orange brown with iodine, owing to the nitrogenous matter which they contain, while parenchyma is not affected by this reagent, aside from the cell contents, nor has it any action on polarized light, remaining quite invisible in the field with crossed prisms.
Next to cellular tissue, starch is the most important element for consideration in the plant, which possesses an organized structure and is distinguished by its reaction with iodine solution, which gives it a deep blue or blackish-blue color, varying somewhat with different kinds of starch and with the strength of the reagent, and its absence is marked by no blue color under the same circumstances.
Heat, however, as in the process of baking, so alters starches, converting them into dextrine and related bodies, that they give a brown color with iodine, instead of a blue-black; they are no longer starch, however; their form, not being essentially changed, permits of their identification, with a study of the size and shape of the granules of the hilum, or central depressions of nucleus, and the prominence and position of the rings. By polarized light and selenite, the starches of tubers showed a more varied play of colors than the cereal and leguminous starches which are produced above ground. The starches we are to consider are those of a limited number to be met with in spices and their adulterants, and one must be able readily to recognize the following:
STARCH NATURAL TO SPICES AND CONDIMENTS
Ginger, Pepper, Nutmegs, Cassia, Pimento, Cinnamon, Cayenne.
STARCHES OF ADMIXTURES
Wheat and other Cereals: Corn, Oats, Barley, Potato.
Maranata and other arrowroots:
Rice, Beans, Peas, Sago, Buckwheat.
No one of these is complete in itself, but from the characters given, and with the aid of illustrations, the starches which commonly occur in substances which are here considered may usually be identified without difficulty.
For the benefit of those who have had no experience with the microscope, I will give the following directions:
Take a small portion of the starch or spice to be examined upon a clean camel’s hair brush and dust it upon a common slide, blow the excess away and moisten that retained with a drop of a mixture of equal parts of glycerine and water, or with glycerine and camphor water, and cover with a glass. It is well to have a small supply of the common starches in a series of tubes which can be mounted at any moment and used for comparison. They may be permanently mounted by making with cork borers, of two sizes, a wax cell ring equal to the diameter of the cover glass and, after cementing the cell to the slide with copal varnish thinned with turpentine and introducing the starch and glycerine mixture, fixing the cover glass on after running some of the cement over the top of the ring. A little experience will enable one to put the right amount of liquid in the cell and to make a preparation that will keep for some time. After several months, however, it is hard to distinguish the rings which mark the development of the granule, and it is better to keep it fresh.
For other purposes, the starches should be mounted in prepared Canada Balsam, or by well-known methods in which they may be preserved indefinitely, but they are scarcely visible with ordinary illumination and must be viewed by polarized light, which will bring out distinctive characters not seen as well, or not at all, in the other mounts. When mounted in the manner described, in glycerine and water, or in water alone, if for temporary use, under a microscope with one objective of equivalent focus of one-half to one-fifth inch, and with means for oblique illumination, the starches will display characteristics which are illustrated in Figs. 2, 3, and 4. The illustrations have been drawn from Nature; Fig. 2 gives starch stained with iodine; Fig. 3 gives shape and size of plain starch, and presence or absence of a nucleus, or hilum, and of the rings and their arrangements which can be made out. The starch is classed in its proper place.
If mounted in balsam, their appearance is scarcely visible under any form of illumination with ordinary light, the index refraction of the granules and the balsam being so similar, but when polarized light is used the effect is a striking one. (See plates of ginger, where it is easy to distinguish all the characteristics, except the rings, the center of the cross being at the nucleus of the granule.)
The principal starches which are met with may be described as follows in connection with illustrations given, beginning with those of the arrowroot class, including potato, ginger, and tumeric.
POTATO STARCH
Potato starch grains are very variable in size, being found from .05 to .10 millimeter in length, and in shape from oval and allied forms to irregular, and even round in the smallest; these variations are illustrated in Fig. 4, but the frequency of the smaller granules is not as evident as in Figs. 5 and 6. The layers in some granules are very plain and in others are hardly visible. They are rather more prominent in the starch obtained from a freshly cut surface. The rings are more distinct near the hilum, or nucleus, which in this, as in all tuberous starches, is eccentric, shading off toward the broader or more expanded portion of the granules.
The hilum appears as a shadowy depression (Fig. 4) and, with polarized light, its position is well marked by the junction of the arms of the cross. It will be found by comparison of Fig. 6 and Fig. 7, that in the potato it is more often at the smaller end of the granules, and that in the arrowroot it is at the larger. With polarized light and a selenite plate a beautiful play of colors is obtained.
The smaller granules, by their nearly round shape, may be confused with other starches, but their presence at once serves to distinguish them from Maranta or Bermuda arrowroot starch. Rarely, compound granules are found composed of two or three single ones each within its own nucleus.
Of the same type as the potato starch are various arrowroots. The only ones commonly met with in this country are the Bermuda, the starch of the rhizome of Maranta arundinacea, and the starch of tumeric.
MARANTA STARCH
The granules are not usually so varied in size or shape as those of the potato, as may be seen in Figs. 8, 9, and 10. They average about .07 millimeters in length. They are about the same size as the average of those of the potato, but are never found as large or as small. This fact, together with the fact that the end at which the nucleus appears is broader in the Maranta and more pointed in the potato, enables one to distinguish the starches without difficulty. With polarized light, the results are similar to those seen with potato starch, and, by this means, the two varieties may be readily distinguished by displaying, in a striking way, the forms of the granule and the position of the hilum, as is illustrated in Figs. 8 and 9.
CIRCUMA
Circuma, or tumeric starch (Fig. 11), though of the arrowroot class, is quite distinct in appearance from these we have described, being most irregular in outline, so that it is impossible to define its shape or to do more than to refer to the illustration. Many of the granules are long and narrow and drawn out to quite a point. The rings are distinct in the larger, and the size is about that of Maranta.
Ginger starch (Figs. 12, 13, and 14) is of the same class as potato and Maranta and several others which are of underground origin. In outline, it is not oval like those named, but is more rectangular, having more obtuse angles in the larger granules and being cylindrical or circular in outline in the smaller; its average size is nearly the same as Maranta starch, but it is much more variable in size and form, the rings being scarcely visible even with most favorable illuminations. Fig. 12 shows ginger adulterated.
LEGUMINOUS STARCHES
Such as those of beans and peas (Figs. 15, 16, 17, and 18), produce but a slight effect under polarized light; the rings are scarcely visible, and the hilum is stellate or much cracked along a median line. This characteristic is more marked in the bean than in the pea. In the latter it resembles fresh dough kneaded again into the center as in making rolls, and in the former the shape assumed by the same after baking. In both it varies in size from .025 to .10 millimeter in length.
NUTMEG STARCH
Fig. 19 has rings scarcely visible and not iridescent with polarized light. It is smaller in size than the preceding, which it resembles, being at times as long as .05 millimeter down to smaller than .005 millimeter, and of extremely irregular form, having angular depressions and angular outlines. It is distinguished by a budded appearance caused by the adherence of small granules to the larger.
CAPSICUM STARCH
Fig. 20 is nearly circular or rounded polyhedral in forms with scarcely visible rings, and in most cases a depressed hilum, resembling in size and shape corn starch, but having peculiar irregularities which distinguish it, such as rosette-like formation on a flattened granule, or a round depression at one end. It does not polarize as actively as maize starch and can be distinguished from rice by the greater angularity of the latter.
PEPPER STARCH
Fig. 21 is the most minute starch which is usually met with, not averaging over .001 millimeter nor exceeding .005. It is irregularly polyhedral and polarizes very well, but requires a high power to discover any detail when a hilum is found. It cannot be confused with other starches.
CINNAMON STARCH
Figs. 22 and 23 have an extremely irregular polyhedral or distorted granules, often united in groups with smaller granules and adherent to the larger ones. In size, it varies from .001 to .025 millimeter, averaging nearly the latter size. In some granules the hilum can be distinguished, but no rings; it is readily detected with polarized light.
BUCKWHEAT STARCH
Fig. 24 is very characteristic. It consists of a chain or groups of angular granules with a not very evident circular nucleus and without rings. The outline is strikingly angular and the size not very variable, being about .01 to .015 millimeter.
MAIZE OR CORN STARCH
Figs. 25 and 26 have granules largely of the same size from .02 to .03 millimeter in diameter, with now and then a few which are much smaller; they are mostly circular in shape or, rather, polyhedral with rounded angles. They form very brilliant objects with polarized light, but with ordinary illumination show but the faintest signs of rings and a well-developed hilum, at times star-shaped and at others more like a circular depression.
RICE STARCH
Figs. 27, 28, and 29, is very similar to corn starch, and is easily confused with it, being about the same size. It is, however, distinguished from it by its polygonal form and its well-defined angles. The hilum is more prominent and more often stellate, or linear, and several grains are at times united.
WHEAT STARCH
Figs. 30 and 31 are quite variable in size, varying from .05 to .012 millimeter in diameter, and this starch belongs to the same class as barley and rye; the hilum is invisible and the rings are not prominent; the granules are circular disks in form, and there are now and then contorted depressions, resembling those in the pea starch; it is the least regular of the three starches and does not polarize actively.
BARLEY STARCH
Figs. 32 and 33 are quite similar to that of wheat, but barley starch does not vary so much in size, averaging .05 millimeter. It has rings more distinct and very small granules adhering to the largest in bud-like forms.
RYE STARCH
Fig. 34 is more variable in size, many of the granules not exceeding .02 millimeter while the largest reach .06 to .07 millimeter. It lacks distinctive characteristics entirely, and is the most simple in form of all starches described.
OAT STARCH
Figs. 35 and 36, is unique, being composed of large compound masses of polyhedral granules from .12 to .02 millimeter in length, the single granules averaging .02 to .015 millimeter. It does not polarize actively, as may be seen in the figures, and displays neither rings nor hilum.
The first sign of maize or corn meal as an adulterant is the thin outer coat which becomes detached in milling and is not readily crushed. In yellow corn it has a pinkish color, and simple, longitudinal cells.
Broken rice is sometimes used as a dilutant; it may be recognized by the brilliant appearance of the hard white particles which may be picked out of the spice under a hand lens.
The two cereals named (broken rice and maize corn) are the only ones which are commonly met with that introduce starch.
Wheat bran (Fig. 37) is occasionally added, which can be recognized by its distinctive structural character and is better understood from an authentic specimen, which should be soaked in chloral-hydrate.
As modified cereals, we find refuse bread, cracker dust, and stale ship bread, in which the wheat starch is much changed from its original form by the heat and moisture, so that at times it might be confused with leguminous starch, but the softness of the particles and the ease with which they fall to pieces in water reveal their true name. Oil seed, oil cake, and husk (Figs. 38, 39, and 40) are very commonly used and are readily recognized by the peculiar structure of the outer coats of the seed. The particles, which can be usually found and selected with a dissecting microscope, should be examined in alcohol or glycerine, or a mixture of the two, as the outer coats of some seeds, such as mustard, are swollen by water and become indistinct. Many varieties of the cruciferous seeds resemble it very much, so that it is difficult to distinguish them, but it is generally recognized by the outer layer of hexagonal cells and a middle and inner coating, which consists of peculiar angular cells, the latter being much larger than the former, which are the most characteristic feature, and should be compared with seeds of known origin. After soaking in chloral-hydrate, the remaining interior layers are, perhaps, more easily made out, in some cases, after moderate bleaching with nitric acid and chlorate; the interior of this seed is not blued by iodine.
Peanut, or ground nut cake, is recognized by the characteristic structure of the red-brownish coat, which surrounds the seed, and consists of polygonal cells with peculiar saw-toothed thickening of the walls. The seed itself consists of polygonal cells full of oil and starch granules, which are globular in form and not easily confused with pepper starch. The structure of the brown membrane is best made out in chloral-hydrate, which removes the red color and leaves the fragments of a bright yellow.
Linseed cake is distinguished by the fact that its husk is made up of one or two characteristic elements. The outer coat, or epidermis, is colorless and swells up in water, forming a mucilage, like the mustard seed. Beneath this is a layer of thin, round, yellow cells, while the third is very characteristic and consists of narrow and very thick-walled dotted vessels; next to these is an inner layer of compact polygonal cells, with fairly thin, but still thickly dotted, white walls and dark-brown contents containing tumeric. The endogen and embryo are free from starch and will not color yellow by potash, as is the case with mustard and rape seed cake.
Cocoanut shells are often used, and have numerous, both long and short, stone cells and spiral vessels from this fibrous tissue; the long stone cells having thinner walls than the shorter cells, all of which are readily seen after bleaching. When the shells are roasted, they refuse to bleach, and it is then only possible to class the particles, on which the reagents do not act, as roasted shells or charcoal, which are frequently used in pepper to give desired color to material rendered too light by white adulterants.
Buckwheat, after bleaching, shows a preponderance of tissue made up of long, slender, and pointed sclerenchyma cells and a smaller amount of reticulated tissue, resembling the cereals somewhat and cayenne pepper. Portions of the interior of the seed are also visible and consist of an agglomeration of small hexagonal cells which originally contained starch. The starch is readily recognized by its peculiar characteristics. The sclerenchyma is, of course, optically active and forms a beautiful and distinctive object with polarized light. Sawdust of various woods may be recognized by the fragments of various spiral and dotted vessels and fibrous material which are not found in spices or in other adulterants.
Rice bran is made up prominently of two series of cells at right angles to each other, which make up the outer coats of grain, the structure being best made out after soaking in chloral-hydrate; the cells of one series are long, small, and thin-walled, and are arranged in parallel bundles; the others have very much thicker walls and are only two or three times as long as they are broad.
Clove stems are distinguished by their peculiar yellow dotted vessels and their large and quite numerous cells, neither of which is seen prominently in the substances which are adulterated. The peculiarities of adulterants should be carefully confirmed and the eye trained by practice so as to become accustomed to recognizing their structure by a study of the actual substance.
Take one gram of powdered spice which will pass a 60-mesh sieve and dry at 150 degrees to 110 degrees C. in an air bath provided with a regulator, until a successive weighing shows a gain, which denotes that oxidization has begun, which takes about 12 hours, or over night; the loss is water, together with the largest part of volatile oil. Deduction of the volatile oil, as determined in the ether extract, will give a close approximation of water. The ash portion is determined by incineration at a very low temperature, such as may be attained in a gas muffle, which is the most convenient arrangement for work of this kind. The proportion of ash insoluble in acid may be determined where there is a reason to believe that sand is present.
To find the amount of volatile oil by ether extract: Two grains of substance are extracted for twenty-four hours in a siphoning extraction apparatus, being first placed in a test tube, which is inserted into a continuous extraction apparatus of the intermittent siphon class, the tube used being an ordinary test tube, the bottom of which has been blown out. A wad of washed cotton of sufficient thickness is put in the lower end of the tubes to prevent any solid particles of the sample from finding their way into the receiving flask; another wad of cotton is packed on top of the sample, and the apparatus is then so adjusted that the condensed ether drops into the tube and percolates through the sample siphons into the receiving flask. In this way the operation is continued the length of time named. The best ether should be used to avoid extracting substances other than oil soluble in alcohol, and to continue the extraction for at least the time named, as piperine and several other proximate principles are not extremely soluble in ether. On stopping the extraction, the extract is washed into a light, weighed, glass dish, and the ether is allowed to evaporate spontaneously, but not too rapidly, for the reason that water, which is difficult to remove, might be condensed into the dish. In a short time the ether will disappear, and the dish is placed in a dessicator with pumice and sulphuric acid, not with chloride of calcium, which has been shown to be useless. It is allowed to remain over night to remove any moisture; the loss of oil by this process is scarcely appreciable. The dish is next weighed and afterward heated to 110 degrees C. for some hours, to drive off the volatile oil, beginning at a low temperature, as the oil is easily oxidized, and then is not volatile oil. The residue is weighed, the difference being calculated to volatile oil and examined as to its composition of purity.
Alcohol extract is made in the same manner as the ether extract, using, of course, the substance extracted. The solvent may be either absolute alcohol—that of 95 per cent. by volume, or 80 per cent. by weight, the latter being preferable in most cases, as there is no definite point with the stronger spirit at which the extraction is completed.
The amount of reducing material produced by boiling the spices with dilute acids serves with several as an index of purity. In the case of pepper, which contains a large amount of starch, the addition of fibrous adulterants reduces the equivalent of reducing sugar, which are indicated in the solution after boiling with acid. Tumeric is always found in spices, such as cloves and pimento of good quality.
It has been said that preliminary extractions of the material with the best ether is necessary to remove oil and other substances, not tannin on which permanganate may act; ordinary ether will not answer, as it contains so much alcohol and water as to dissolve some of the tannin.
The substance freed from ether should be extracted with boiling water and the extract made up to such dilution that 10 CC. is equal to about 10 CC. of the thirtieth normal,—permanganate solution used. The titration must be performed slowly to insure accuracy, the permanganate being run in at the rate of not more than a drop in a second, or three drops in two seconds. The eye must become accustomed to the bleaching of the indigo used, and select some one tint of yellow, as the end of reaction is then possible to duplicate. That part of the material analyzed, which is insoluble in acid and alkali of certain strength after treatment for a definite length of time, at a definite temperature, is called _crude fiber_, and it may be described as follows: Select two grains of substance 200 CC. of 5 per cent. hydrochloric acid; steam bath two hours, raising the liquid to a temperature of 90 degrees to 95 degrees C. filtration on linen cloth, washing back into beaker with 200 CC. 5 per cent. sodic-hydrate; steam bath two hours, filtration on asbestos, washing with hot water, alcohol, and ether, drying at 120 degrees, weighing, ignition and crude fiber from loss in weight.
REAGENTS AND APPARATUS
(1). Hydrochloric acid whose absolute strength has been determined.
(a). By precipitating with silver nitrate and weighing the silver chloride.
(b). By sodium carbonate, as described in Fresenius Quantitative Analysis, second American edition, page 680.
(c). by determining the amount neutralized by the distillate from a weighed quantity of pure ammonium-chloride boiled with an excess of sodium-hydrate.
(2). Standard ammonia whose strength relative to the acid has been accurately determined.
(3). C. P. sulphuric acid specific gravity 1.83, free from nitrates, and also from ammonium sulphates, which are sometimes added in the process of manufacture to destroy oxides of nitrogen.
(4). Mercuric-oxide, HgO, prepared in the wet way. That prepared from mercury nitrate cannot safely be used.
(5). Potassium permanganate tolerably finely pulverized.
(6). Granulated zinc.
(7). A solution of 40 grams of commercial potassium-sulphide in one liter of water.
(8). A saturated solution of sodium-hydrate, free from nitrates which are sometimes added in the process of manufacture to destroy organic matter and improve the color of the product.
(9). Solution of cochineal, prepared according to Fresenius Quantitative Analysis, second American edition, page 679.
(10). Burettes should be calibrated in all cases by the user.
(11). Digestion flasks of hard, and moderately thick, well-annealed glass, which should be about 9 inches long, with a round, pear-shaped bottom, having a maximum diameter of 2½ inches and tapering out gradually in a long neck, which is three-fourths of an inch in diameter at the narrowest part and flared a little at the edge. The total capacity is 225 to 250 cubic centimeters.
(12). Distillation flasks of ordinary shape, 550 cubic centimeters capacity, and fitted with rubber stoppers, and a bulb tube above to prevent the possibility of sodium-hydrate being carried over mechanically during distillation; this is adjusted to the tube of the condenser by a rubber tube.
(13). A condenser with tube of block tin is best, as glass is decomposed by steam and ammonia vapor, and will give up alkali enough to impair accuracy; the tank should be made of copper, supported by wooden frame, so that its bottom is 11 inches above the workbench on which it stands. It should be about 16 inches high, 32 inches long, and 3 inches wide, gradually widening 6 inches toward the top; the water-supply tube should extend to the bottom, and there should be a larger overflow pipe above.
The block tin condensing tubes should be about ⅜ of an inch inner measure and seven in number, entering the tank through holes in the front side of it near the top above the level of the overflow, and pass down perpendicularly through the tank and out through the rubber stoppers, tightly fitted into holes in the bottom; they should project 1½ inches below the bottom of the tank, and connect by short rubber tubes, with glass bulb tubes, of the usual shape, which dip into glass precipitating beakers. These beakers should project about 6½ inches high by 3 inches in diameter below, gradually narrowing above, and should be about 500 cubic centimeters capacity. The titration can be made directly in them. The seven distillation flasks should be supported on a sheet-iron shelf attached to the wooden frame which supports the tank at the front; where each flask is to stand, a circular hole should be cut with three projecting lips to support the wire gauze under the flask, and three other lips to hold the flask in place, and to prevent its moving laterally out of place while distillation is going on. Below the sheet-iron shelf should be a metal tube carrying seven Bunsen burners, each with a stopcock like those of a gas combustion furnace. These burners are of larger diameter at the top, which prevents smoking when covered with fine gauze to prevent the flame from striking back.
(14). The stand for holding the digestion flask should consist of a pan of sheet iron, 29 inches long by 8 inches wide, on the front of which is fastened a shelf of sheet iron as long as the pan, 5 inches wide and 4 inches high. In this are cut six holes 1⅝ inches in diameter. At the back of the pan is a stout wire running lengthwise of the stand, 8 inches high, with a bend or depression opposite each hole in the shelf. The digestion flask rests with its lower part over a hole in the shelf and its neck in one of the depressions in the wire frame, which holds it securely in position, and heat should be supplied with Bunsen burners below the shelf.
THE DETERMINATION
One gram of the substance to be analyzed is brought into a digestion flask with approximately 0.7 grams of mercuric-oxide, and 20 cubic centimeters of sulphuric acid, and the flask is placed on the frame described in an inclined position, and heated below the boiling point of the acid for from five to fifteen minutes, or until frothing has ceased. The heat is then raised until it boils briskly. No further attention is required until the contents of the flask have become a clear liquor, which is colorless, or, at least, has only a very pale straw color. The flask is then removed from the flame, held upright, and, while yet hot, potassium permanganate is dropped in carefully and in small quantities at a time until, after shaking, the liquid remains of a green or purple color.
After cooling, the contents of the flask are then transferred to the distilling flask with water, and to this 25 cubic centimeters of potassium-sulphide solution are added, 50 cubic centimeters of the soda solution, or sufficient to make the reaction strongly alkaline, and with a few pieces of granulated zinc.
The flask is at once connected with the condenser and the contents of the flask are distilled until all of the ammonia has passed over into the standard acid contained in the precipitating flask previously described and the concentrated solution can no longer be safely boiled.
This operation usually requires from 20 to 40 minutes. The distillate is then titrated with standard ammonia. The use of the mercuric-oxide in this operation greatly shortens the time necessary for digestion, which is rarely over an hour and a half in the case of substances most difficult to oxidize, and is more commonly less than an hour.
In most cases the use of potassium permanganate is quite unnecessary, but it is believed that in exceptional cases it is required for complete oxidation, and, in view of the uncertainty, it is always used.
Potassium-sulphide removes all mercury from solutions and so prevents the formation of mercuro-ammonium compounds which are not completely decomposed by soda solution.
The addition of zinc gives rise to an evolution of hydrogen and prevents violent bumping. Previous to use, the reagents should be tested by a blank experiment with sugar, which will partially reduce any nitrates that are present which might otherwise escape notice.
This method cannot be used for the determination of nitrogen substances which contain nitrate or certain albumenoids.
These methods of analysis are suitable to all spices and have been used with them. They are but a general process, however, and are dependent for their value on uniformity in the way they are carried out and the manner in which peculiarities of proximate composition in different spices are considered in drawing conclusions; determinations of particular substances, such as piperine, require, however, modifications, which must be described when discussing the analysis of each separate spice.
The chemical composition of olive stones and cocoanut shells is about as follows:
Water, 5.63 6.15 Ash, 4.28 2.15 Fiber, 41.33 37.15 Albumenoids, 1.56 1.25 Nitrogen, .25 .20