Chocolate is a mixture of cacao mass with sugar, to which usually spices and even cacao butter are also added. The sugar generally amounts to rather more than one half (60 percent) of the total mixture. Spices such as cinnamon, vanilla, cloves, nutmeg, mace, cardamoms, as well as cacao butter, or perfumes like peruvian balsam, are only added in small quantity so as to improve or alter the flavour as required. Recently, the ethereal oils of the spices have been used for this purpose as well as artificially prepared aromatic substances, such as vanillin, for example. Flour and starch136, although the latter is seldom used, are permissible ingredients in cheaper kinds of chocolate but only when the fact of the addition is plainly stated. The kinds of flour usually employed are wheat and potato flours, rice-starch and arrowroot, dextrin and, less frequently, oat, barley, acorn, chestnut, or rye flour. In certain forms of dietetic chocolate, sugar being injurious to invalids, it is replaced by saccharin; another material, such as a leguminous flour from beans, peas or lentils, must be employed in its place.137 In some kinds of fancy chocolate, harmless colours, tincture of benzoin etc. are used.
Both cane and beetroot sugar are employed in the manufacture of chocolate. As this naturally possesses a brownish colour, brownish white as well as white sugar is used for mixing with the cacao mass. The kinds of sugar used are:
1. Sugar dust, a white crystallisable and very fine powder.
2. Crystal or granulated sugar, consisting of loose, plain crystals, and suitable for almost all purposes in the manufacture.
3. Sugar flour I, II, and III which is a difficultly crystallisable sugar containing an amount of molasses increasing with the number, and it is of a more or less brown colour.
The chocolate manufacturer nevertheless requires the sugar to answer to certain characters. It must dissolve in half its weight of warm water forming a sweet syrup. The syrup must have no action on either red or brown litmus paper i. e. have neither acid nor alkaline reaction, and on no account coagulate boiling milk.
The sugar is usually added to the cacao mass in the form of a very fine powder and sometimes in a coarser condition, though that is not to be recommended. By using finely powdered sugar, the rolling of the cacao mass is considerably facilitated and the manufacture is accelerated. The sugar must be perfectly dry, as damp sugar yields a dull chocolate which readily crumbles.
For grinding the sugar, the so called edge-runner mill as shown in figure 94 was formerly employed.
It is like the melangeur constructed of a firmly fixed bed-stone and two cylindrical runners.
The pulverised material issuing from such an apparatus must then be passed through one of the various kinds of sifting machines, where the finer parts fall through the meshes of a silken sieve, whilst the rougher are discharged at the end of the arrangement: for small factories such machines as the drum sifters illustrated in fig. 95, and for the larger those centrifugal sifters which have already been fully described.
The constructions for grinding have of late been considerably perfected. The most practical arrangements for pulverising all kinds of granulated sugar and so-called lump sugar, are those combined grinding and sifting installations such as are executed by the firm of J. M. Lehmann in Dresden. The grinding is here effected by disintegrators (revolving arms, etc.) similar to those used in the pulverising of cocoa powder as described on page 212. The output of these disintegrators138 is extraordinarily large, and the harder and drier the ground sugar is, the finer the pulverised material resulting. We annex a diagram of the machine in fig. 96.
The granulated or lump sugar is filled into the hopper and thence lead along a conveyor to be ground in another part of the machine, and can be controlled as regards quantity. The blades, which pass through about 3000 revolutions a minute, seize the sugar and swing it against the ribbed walls of the mantle, after which it falls in smaller fragments on a grater fitted in the under part of the apparatus. The sugar which passes through the grating is now conducted by conveyor and elevator to the sifting arrangement, whilst the rougher material is again whirled round by the blades. This sifting arrangement consists of a cylindrical sieve, on the interior of which there occur revolving arms which provide for the despatch of material through the various sieves. The rougher stuff which remains is removed by hand or some other mechanical means and transported to the hopper once more. A chamber placed above the machine and connected with the grinding apparatus by means of pipes provides for the protection of the machine against dust.
Such installations are constructed in various sizes and fashions, and possess immense outputs (up to even 5000 kilogrammes daily). That they must be built in special shops is clear from the fact that so large a quantity of dusty sugar sacks need transporting after the processes are completed. It is further to be noted that the fineness of the sugar corresponds to the mesh-work of the sieves, which as we have previously stated, can be chosen with any size of hole desired, yet this naturally influences the machine, and recently a very high standard of fineness has been generally dropped, and rougher siftings are now made, as when the sugar is too fine.—e. g. in the case of the cheaper qualities—it absorbs too much of the fatty contents, and so necessitates the addition of cacao butter, whilst on the other hand, when the chocolate is of a finer quality, the sugar is sufficiently reduced in the trituration to which the mixed material is subjected.
Apart from the sugar, which is such an important factor in the chocolate manufacture, mention must also be made of another sweetening material, formerly frequently used as a substitute for sugar, but now only to be obtained at the apothecary’s on exhibition of a medical order, in consequence of certain legal restrictions which have recently come in force. It is called Fahlberg saccharin, and again zuckerin, sykorin, crystallose, “Süßstoss Höchst” and sykose.
Saccharin is not like sugar a carbohydrate naturally produced by plants, but a derivative of the aromatic compounds which the chemist has artificially constructed from the products of the distillation of coal.
Saccharin is benzoyl-sulphonimide, and it has the chemical formula
| C6H4≺ | CO | ≻NH |
| SO2 |
It is a white, crystalline powder, so exceedingly sweet that its taste can be perceived in a dilution of 1 in 70000. It is only slightly soluble in cold water (1: 400) but more easily so in hot water (1: 28). The material known as easily soluble saccharin is its sodium salt. It contains 90 percent of saccharin and is the most easily digested compound of saccharin.
For technical, domestic and medicinal purposes the soluble saccharin which is only from 300-450 times as sweet as sugar is employed. Besides being unfermentable saccharin has very slight antiseptic properties; according to L. Nencki139 the digestibility of albumin is less affected by it, in the proportion usually added to articles of food, than by Rhine wine, or by a sugar solution of equal sweetness. Saccharin is entirely unaltered in the human organism, hence it forms a welcome sweetening material for invalids suffering from diabetes, corpulence or diseases of the stomach to whom ordinary sugar is injurious. The substances known as dulcin and glucin are analogous to saccharin in sweetening property, the first being phenetol-carbamid and the latter a monosulphonate of amido-triazine.
The latest substance of this class is termed “sucramin” and consists of the ammonium salt of saccharin. It is readily soluble in water, less so in alcohol and is 700 times sweeter than sugar. It can be obtained either in the pure form or mixed (20 percent) with sugar.
In chocolate making, saccharin is at present of little importance, owing to the relatively small volume required as compared with sugar. Recently it has again been recommended to the extent of 0·76 percent as a sweetening material for cocoa powder. It would certainly be of value in cocoa powders to be consumed by invalids and persons not able to take sugar, although it will never come into general use. The detection of saccharin has acquired increased importance in Germany since the passing of the acts of October 1st 1898 and July 7th 1902, regulating the trade in artificial sweetening materials. According to Zipperer’s experiments, it may be detected in the following manner: A mixture of 5 grammes of the finely powdered substance with 100 ccm of water is allowed to stand for 2 hours, occasionally stirred and afterwards filtered. The filtrate is acidulated with three drops of hydrochloric acid and evaporated to 20 ccm, then shaken140 with 50 ccm of ether in a separator and left standing for a day to separate into two layers. The ether solution is separated and evaporated to dryness in a beaker, the residue being mixed with 0·1 gramme of resorcin and 4-5 drops of concentrated sulphuric acid141 (Börnsteins test). The mixture is then heated over a small Bunsen flame and the melted material saturated with normal sodium hydrate. The appearance of a strong fluorescence indicates the presence of saccharin. Saccharin can also be easily recognised by the sweet taste of the ether residue.
The chief kinds of starch used in chocolate making are rice starch, arrowroot, potato starch and wheat starch, occasionally also small quantities of dextrine.
Potato starch is a white or faintly yellowish powder in which single, glistening granules can be seen by the naked eye. Under the microscope the granules appear mostly single with evident striae, usually with pointed ends containing the nucleus; they are also eccentric in structure. This starch rarely contains fragments of tissue. It is prepared by first treating finely divided pared potatoes with 1 percent dilute sulphuric acid, then washing, drying and grinding the starch.
Wheat starch can be obtained either from crushed wheat or from wheaten flour by treatment with water after the nitrogenous constituent, gluten, has been separated by kneading. It amounts to about 60-70 percent of the grain. Under the microscope the granules appear to differ considerably in size. They are distinguished from potato starch by the nearly central hilum, surrounded by faintly marked concentric striae, and again by the granules being more frequently adherent. Wheat flour rather than the starch is generally used in chocolate making.
When starch is heated to between 200° and 210° C. it is converted chiefly into dextrin or starch gum with a little sugar. Dextrin is a white to yellowish and tasteless powder with a peculiar smell; it differs from starch in being readily soluble in water. It gives a reddish colour with an aqueous solution of iodine. Fehling’s solution is unaffected by dextrin in the cold, but on long continued heating it is reduced to red cuprous oxide.
Rice starch is obtained from inferior kinds of rice and from rice waste by treatment with water. It appears under the microscope as small granules or oval bodies of various sizes. According to their position the granules always seem to be polygons,142 formed by coalescence. It is thus easily distinguished from the previously mentioned starches.
Several kinds of starch, obtained from the tubers of various species of plants are commercially known under this name.
1. West Indian arrowroot, from Maranta arundinacea, is a fine and almost white powder. Under the microscope it always appears to consist of pear or spindle-shaped granules with eccentric hilum.
2. East Indian arrowroot is obtained from various species of ginger plants. It is a fine white powder and is seen under the microscope as single granules with well marked eccentric hilum and closely stratified at the spindle-shaped ends. It much resembles Guiana arrowroot, which is obtained from varieties of Yam.
3. Queensland arrowroots from species of Cycas and Canna, appear as flat, coarse and mostly single granules. They can be easily distinguished from other kinds of starch by the large size of the granules.
4. Brazil arrowroot, from the Manihot plants which belong to the order of Euphorbiaceae. Under the microscope the granules appear compound, the parts being of a drum or sugar loaf shape with many concentric striae.
Chestnut or maron meal also comes under consideration in the chocolate industry. The appearance of the starch granules is most characteristic. They are partly single and partly composed of two individual granules. The single granules, according to J. F. Hanausek143, appear in such a variety of forms as to defy a summarised description. Frequently they occur oval, spindle, club, or flat kidney shaped, resembling those of the leguminous family; but especially to be noticed is the triangular contour of some granules, as well as some with projecting points. The central nucleus and its cavity are generally distinct, but the stratification is very slight or quite unrecognisable.
Of the leguminous meals that of beans is chiefly used as an adjunct in cocoa powders and chocolate, sweetened with saccharin, on account of its relatively large proportion of albuminous substance and small amount of starch. The meal is generally obtained from the seed of the common white bean. (Phaseolus vulgaris.) The starch granules under the microscope appear oval or long kidney shaped, with distinct nucleus cavities and furrows, as well as a distinctly marked stratification. Their length averages from 0·033 to 0·05 mm. The meal has a disagreeable leguminous taste when cooked, but that disappears when the meal is slightly roasted.
Salep which is now very seldom used as an admixture to chocolate (Rakahout of the Arabs)144 is an amylaceous powder prepared from the tubers of various kinds of orchids. Under the microscope salep appears as fairly large translucent masses which consist of an agglomeration of very delicate walled cells giving the starch reaction with iodine.
We cannot too strongly recommend the manufacturer to pulverise the spices, e. g. cinnamon, cloves and the like, himself, for such as are bought ready pulverised have frequently been adulterated with admixtures of wood, flour or bark. This is the more essential as sometimes pulverised cinnamon is distilled with steam to obtain an extract of its ethyl oil, and then the residue, which is of considerably inferior value as regards aroma, sold as genuine cinnamon powder. Such adulteration can neither be demonstrated under the microscope nor chemically, so that it is impossible to protect oneself against them.
The edge runner mill and sieving apparatus described in connection with the pulverising of sugar also adapt themselves to reducing spices, although generally other machines are used for this purpose, either the well-known ball mills145 consisting of a hollow spherical ball revolving round its axle, inside which the spices are shaken, crushed and completely pulverised by the action of a number of heavy metal balls, or in other cases pulverising mills and stamping arrangements proper.
The following stamp arrangement, shown in fig. 97, is very practical in the pulverisation of all manner of spices, and is driven by a force of 1·5 H.P. The strong frame, which is walled in with iron, is dust-proof. Whilst the stamper is being raised, the pots are revolved round their axles, and so the substances to be pulverised are mixed together. Other machines much used in pulverising are seen in fig. 94. Another smaller pulverising mill is pictured in fig. 98. This machine is adapted for a middle sized production. The grinding arrangement in which the pulverising takes place is conically built and is made completely of granite; the regulation is effected by means of a working beam, the batting arm of which is fitted on to the upper part of the apparatus. A sieving of the material to be pulverised does not generally take place in this machine. For small production for example for confectioners who manufacture chocolate also incidentally, one can also use the machines pictured in the figs. 95 & 99, the method of working of which may be at once understood. The different degrees of fineness of the material to be pulverised are reached by passing the powder through drum sieves of different widths of mesh and all the sieves are set in motion at the same time by the machines.
Only the most important features of the spice so valuable in chocolate making will be noticed, since the characteristic aroma of the true vanilla has been to a large extent supplanted in practice by artificially prepared vanillin.
Vanilla is the fruit capsule of an orchid, Vanilla planifolia, which is generally cultivated with the cacao tree, as the same climate and soil suit them equally. According to Möller, the shoots of the vanilla are fastened to the cacao tree, on the bark of which they soon strike root. The aerial roots and tendrils then put forth fleshy leaves, in the axils of which arise large odourless and dull coloured flowers which yield after a lapse of two years long thin capsules. The capsules are filled with a transparent balsam, in which the black seeds are imbedded. It is in the balsam that the vanillin, which gives vanilla its unequalled aroma, is produced. The fresh gathered vanilla fruit (see the investigations of W. Busse146 contains no free vanillin or merely an infinitesimal quantity.
It is rather developed by subsequent treatment in which heat appears to be necessary. Vanillin, like cocoa-red and theobromine, is formed by the splitting up of a glucoside by fermentative action. In some kinds of vanilla, piperonal, an aromatic body, which occurs in larger quantities in Heliotropium europaeum and peruvianum, has also been observed.
The commercial kinds of vanilla come from Mexico, Tahiti, Réunion, Mauritius, Mayotte, Seychelles, Ceylon and Java, which in 1891 produced respectively:
| Réunion (Bourbon) | 50-65,000 | kilos |
| Mexico | 55,000 | " |
| Mauritius | 13-15,000 | " |
| Mayotte (Comoro Islands) | 8-10,000 | " |
| Seychelles | 4- 6,000 | " |
The best commercial kinds of vanilla come from Mexico, Bourbon, and Mauritius, and command a higher price than the other kinds. The quantity is gauged by the length (10-24 cm), and plumpness of the pods. Fine quality is fatty and dark coloured, inferior quality is dry and reddish. The outside of the pods in the Bourbon vanilla, contains highly esteemed vanillin crystals, which are wanting in the Mexican variety. Vanilla flowers in October and November, is gathered in the following months of May, June, and July, and is prepared in October and November. At the beginning of November the first instalment of the new harvest arrives in Marseilles, which is the chief commercial place for vanilla. The most important operation, in preparing vanilla is to attain the proper degree of dryness. This is arrived at nowadays by the use of calcium chloride. The pods are first placed in a metallic box lined with wool which is placed in warm water so as to superficially dry them; they are then transferred to a suitable constructed drying closet containing calcium chloride and allowed to remain there for 20-30 days. 100 pounds of vanilla are reckoned to require 40 pounds of calcium chloride. The great advantage of this process is that the fruit, so dried, better retains its aroma.147 Insufficiently dried vanilla does not keep, but soon becomes mouldy, whilst overheated vanilla keeps well, but is brittle, breaks easily and consequently has little commercial value. Vanilla covered with mould (Aspergillus repens and Mucor circinelloides) is sought to be improved in various ways and is sold as of inferior quality.148 It is worth observing that those persons who in the course of business handle vanilla show characteristic symptoms of poisoning. It affects the eyes and nervous system and produces eruptions on the skin. The complaint, however, is not of a dangerous nature, for the workmen quickly become accustomed to vanilla so that, after recovering from the first attack, they can resume work without risk to health.149
On account of its high price, vanilla is much subjected to adulteration; either by an admixture of the more cumarin-smelling vanillin (Pompona or La Guayra Vanilla [Vanilla Pompona Schieder]) or other less valuable vanilla fruit; sometimes pods that have been deprived of vanillin by extraction with alcohol are used for that purpose; their colour and appearance being restored by immersion in tincture of benzoin and coating with crystals of benzoic acid, powdered glass etc. In doubtful cases of adulteration the vanillin must be quantitatively determined.
That can be done by W. Busse’s method150, in which the vanilla is extracted with ether in a Soxhlet’s apparatus. The extract is shaken with a solution of sodium bisulphite, the vanillin then set free with sulphuric acid and the disengaged sulphurous acid removed by a stream of carbon dioxide. The vanillin is then shaken out with ether and on evaporating off the ether, vanillin is left in a pure condition. Busse found by this method in East African vanilla 2·10 percent of vanillin, in the Ceylon 1·48 percent, and in the Tahiti variety from 1·55 to 2·02 percent. In America the so-called vanilla extract, instead of vanilla, is used and it lends itself to adulteration much more easily than natural vanilla. William Hesse has given methods and results obtained in the investigation of the extract.151
5. Vanillin.
Vanilla in the chocolate industry has recently been almost entirely superseded by the use of artificially prepared vanillin, which serves as a complete substitute for the essential and valuable constituent of vanilla. In comparing vanillin with vanilla, regard must be had to the amount of vanillin in the latter, which may vary to the extent of 50 percent according to whether the vanilla was damp, dry, fresh or stored. The finest kinds of vanilla seldom contain more than 2 percent of vanillin and in many kinds it varies between 0·5 and 2·5 percent. It may also happen that vanilla with 0·5 to 1·0 percent may be equally as fine in appearance as one of high percentage, hence the aroma value must be taken into consideration. In addition to possessing a uniform and permanent perfume vanillin is cheaper in price.
Vanillin occurs naturally not only in vanilla but also in very small amount in certain kinds of raw sugar, in potato skins and in Siam benzoin; it can be produced artificially from coniferin which is obtained from pine wood, or by the oxidation of eugenol, a substance contained in oil of cloves, from both of which Tiemann and W. Haarmann152 first prepared it in 1872. In the course of the last ten years a number of processes have been discovered whereby vanillin can be artificially produced. The reader who is interested in this subject will find it fully discussed in a paper by J. Altschul in No. 51 of the Pharmazeutische Centralhalle 1895.
The competition which arose through the processes of Haarmann and Reimer of Holzminden and G. de Laire of Paris, whose products owing to patent rights had controlled the market from the commencement, produced a steady decrease in the price of vanillin.
The following table drawn up by J. Rouché153 shows the revolution in price which has occurred in this article and how, in the course of time, a small business with large profits has been transformed into a large business with small profits.
The variation in the price of vanillin:
Marks per Kilo.
| 1876 | 1877 | 1878 | 1879 | 1881 | 1882 | 1884 | 1885 |
| 7000 | 4000 | 2400 | 1600 | 1600 | 1600 | 900 | 900 |
| 1886 | 1888 | 1890 | 1892 | 1893 | 1895 | 1897 |
| 700 | 700 | 700 | 700 | 700 | 560 | 108 |
The chemical formula of vanillin is C6H3(OCH3) (OH)CHO; it melts between 82-83 ° C. and sublimes at 120 ° C. The colourless four-sided crystals have a strong vanilla odour and taste, are difficultly soluble in cold water, easily in hot water and very readily soluble in alcohol.
Vanillin is much adulterated. Cumarin, the aromatic principle of the melitot (meliotus officinalis) and of tonquin beans etc., can be prepared cheaply and it is fraudulently used in large or small quantity to imitate the vanillin aroma. A sample of vanillin bought in Switzerland was found by Hefelmann154 to contain 26 percent of antifebrin. The American “vanilla crystals” consist of a mixture of vanillin and antifebrin, or vanillin, cumarin and benzoic acid; latterly that article is stated to consist only of cumarin, antifebrin and sugar.
The melting point of genuine vanillin is a characteristic indication. Admixtures of vanillic acid and antifebrin cause depression of the melting point (4-8 ° C. according to the amount and character of the two substances [Welmans])155. For the quantitative determination of vanillin in mixtures, Welmans takes advantage of its behaviour towards caustic alkalis, with which, like phenol, it forms compounds that are easily soluble in water, but sparingly so in alcohol. The process is as follows: 1 gramme of the substance is placed in a cylinder of 200 ccm capacity with 25 ccm of alcohol, 25 ccm of approximately semi-normal alcoholic potash and 2 or 3 drops of phenolphthalein solution and agitated until completely dissolved. The excess of alkali is then titrated with semi-normal hydrochloric acid, and, at the same time, the strength of the alcoholic potash after adding 25 ccm of alcohol is ascertained. The number of cubic centimetres consumed is multiplied by 0·076, the semifactor for vanillin. In the case of vanilla sugar, 10 grammes are treated with 50 ccm of water to dissolve the sugar, then the alcoholic potash is added and the operation carried out as before described.
1 gramme of vanillin requires 6: 58 ccm of normal potash (= 0·36842 g KOH).
| C6H3(OH) | ∕ OCH3 | : KOH |
| ∖CHO | ||
| 152 | : 56 = 1 : x |
If cumarin is suspected to have been added to the vanillin it can be detected and separated, according to Zipperer’s experiments, by the method of W. H. Hess and A. B. Prescott.156
The substance is dissolved in ether and the solution shaken up with a weak solution of ammonia. The vanillin will be found in the aqueous layer in the form of an ammonium compound, whilst the cumarin will be dissolved by the ether. The vanillin can be identified by the sandal-wood oil reaction as described by Bonnema,157 and the cumarin can be determined by direct weighing.
The financial advantage in using vanillin in place of vanilla is apparent. The average price of vanilla is now 45 to 50 shillings per kilo. But as 25 grammes of vanillin are equal in perfume to 1 kilo of vanilla and, at the rate of 35 shillings per kilo, that quantity costs only 10½ vanilla is nearly sixty times dearer than vanillin. The consumption of vanillin has increased to an enormous extent, and in the United States Henning has estimated the consumption during 1897-1898 at over 100000 ounces. The same author points out the remarkable fact that this enormous consumption of vanillin has scarcely any effect on the demand for vanilla pods, the market value of which is not only maintained but has a tendency to increase.
In order to have it in a finely divided condition, as required for the factory, it is recommended to rub the vanillin down with sugar, in the proportion of 100 grammes of vanillin to 2 kilos of sugar, in the following manner; 100 grammes of vanillin are dissolved in 500 grammes of hot alcohol and this solution added to 2 kilos of finely powdered sugar; then the whole is placed in a rotatory comfit boiler and dried by a blast of warm air at 40 ° C. Whilst vanilla must be very carefully packed that it may not become mildewed and deteriorate, vanillin on the other hand keeps very well in such mixtures so long as they are kept from damp, which might cause the sugar to ferment and thus gradually decompose the vanillin.
There are three commercial kinds of cinnamon in Europe.
1. Ceylon cinnamon, which represents the finest kind, is the bark of Cinnamomum ceylanicum, a native of the island of Ceylon. The bark is very light and brittle, seldom more than 0·5 mm thick, externally yellowish brown with long stripes, whilst it is somewhat darker on the inside. Its fracture is short and fibrous, and a traverse section shows externally a sharply defined light colour with a darker inside zone.
2. Cassia or Chinese cinnamon is from Cinnamomum Cassia, a tree which grows wild in the forests of Southern China. The bark is thicker than that previously described, often 2 mm thick. It is in single tubes, harder and thicker than the Ceylon kind, with frequently adherent fragmentary tissues of the corky layer. The colour is a greyish brown, the fracture even, with a light zone in the section.
3. Malabar or wood cinnamon consists of the less valuable kinds and is derived from different varieties of cinnamon trees which have been planted in the Sunda and Phillipine islands. In appearance it resembles the Chinese more than the Ceylon cinnamon.
The aromatic taste of cinnamon is due to the ethereal cinnamon oil which, in Ceylon cinnamon, amounts to 1 percent; the ash should not exceed 4·5 percent. An ethereal oil is also present (about 1·8 percent) in the leaves of the Ceylon cinnamon tree, but it is quite different from the bark oil, resembling in its properties more the oils of cloves and pimento. On account of its penetrating odour and pungent taste its employment in chocolate making is little to be recommended.
It cannot be too much insisted on that with spices like cinnamon, cloves, etc. the manufacturer should grind them himself and not purchase them in fine powder, as the latter is frequently adulterated with admixtures of wood, meal bark, etc. This is more to be recommended as ground cinnamon has frequently been deprived of the ethereal oil by distillation with steam and the bark then flavoured with a small amount of cinnamon oil and sold as powdered cinnamon. Such an adulteration can be detected neither chemically nor microscopically.
Cloves are the incompletely developed flowers of the clove tree, Caryophyllusaromaticus of the Myrtaceae. The most important commercial kinds are the Zanzibar, Amboyna, and Penang cloves. The aromatic principle of cloves is an ethereal oil which they contain to the extent of 18 percent. The adulteration of cloves is much the same as in the case of cinnamon. Genuine cloves should not give more than 6 percent of ash.
Nutmeg is the seed kernel of the fruit of Myristica moschata known as the nutmeg tree, which is indigenous to Malacca. In the thick pericarp of the fruit, resembling the apricot, is found the brown seed surrounded by a deep red reticular mantle. This last is the seed mantle or arillus and when separated from the kernel is known commercially as mace.
The furrows on the surface of the nutty seeds are filled with a white mass which consists of lime, in which the nuts have been laid after drying in order to protect them from the attack of insects. The aromatic constituent of nutmeg and of mace is also an ethereal oil. The seeds contain 8-15 percent of ethereal oil with 25 percent of a fatty oil; mace contains 4-15 percent of ethereal oil and 18 percent of fatty oil. As both spices occur in commerce in whole pieces, adulteration is not to be feared.
Of these there are two kinds on the market:
1. The small or Malabar cardamoms.
2. The long or Ceylon cardamoms.
Both are the fruit, although very different in form, of a species of the ginger plants which is indigenous to Ceylon and Malabar.
The Malabar cardamom is three cornered oblong and about 1 cm in size. In the fine brown pericarps are enclosed, adhering together, 6-8 angular seeds, 3 mm in size, having a pungent aromatic taste.
The Ceylon cardamom is four times larger than the Malabar kind. The grey brown pericarp encloses about 20 dark greyish brown seeds about 6 mm large. The aroma of the Ceylon cardamom is due to an ethereal oil which it contains in quantities sometimes reaching 6 percent. Madras and Malabar cardamoms contain 4-8 percent of ethereal oil. As the Ceylon cardamoms are cheaper than the Malabar kind a confusion of the two seeds might possibly be to the disadvantage of the buyer, but the above description of their relative size would suffice to distinguish them.
Exact accounts of the characteristic properties, the chemical and microscopical investigation as well as of the impurities and adulterations of the materials previously mentioned as being used in cacao preparations are to be found in volume II of the “Vereinbarungen zur einheitlichen Untersuchung und Beurteilung von Nahrungs-und Genußmittel sowie Gebrauchsgegenständen für das Deutsche Reich”158 to which those who desire further to investigate this subject are referred.
As previously remarked in the case of vanillin, it is becoming more and more the custom to substitute perfume substances for powdered spices. This practice is quite justified since the entire perfume of a spice is made use of and the worthless woody and indigestible fibre is thus excluded from the finished preparation.
The following are the ether oils used in practice:
The amount of ether oil that should be used in place of the corresponding spice is a matter of taste. The maximum percentage of the oil in the respective spice might serve as a standard, as for example in the case of cinnamon oil, which is contained in the bark to the extent of 1 percent, about the hundredth part of the oil would be required to correspond with the prescribed weight of the bark. But as the yield of oil from one and the same kind of spice varies to a considerable extent according to season and locality, the percentage value can only be used as a general guide, and the final decision must be always regulated by the taste.
The ethereal oils can be incorporated in the cacao preparations (mass, powder etc.) either in a spirit solution or ground down with sugar. The latter method is naturally only used when sugar is to be added to cacao preparations. To prepare the alcoholic solution 10 parts of the ethereal oil are dissolved in 90 parts of strong alcohol. The mixture of oil with sugar can be made by triturating 2·5 parts of the ethereal oil with 100 parts of sugar in a porcelain mortar and grinding down with the pestle until the sugar and oil are intimately mixed. Of the alcoholic solution it is necessary to take 10 parts, and of the oil-sugar 40 parts to one part of ethereal oil.
Peru balsam is at present very much used as a perfume in chocolate making. It is obtained from the Papilionaceous Myroxylon Pereira which is indigenous to the western part of Central America. It is a thick, brownish black, liquid balsam which in thin layers appears transparent and has a peculiar smell and burning taste; it is almost completely soluble in alcohol, chloroform, and acetic ether. The aromatic substance of this balsam is cinnameïn, which consists essentially of the esters of benzoic and cinnamic acids and benzyl alcohol together with an alcoholic body “Peruviol”, which has the smell of honey. In addition to cinnameïn (71-77 per cent) the balsam also contains a resin ester (13-17 percent). According to K. Dieterich, Peru balsam is the better for containing more cinnameïn and less resin ester. Peru balsam is adulterated with fatty oils, copaiva, gurjun-balsam, storax, colophony, turpentine, and tolu balsam. In regard to the chemical investigation of this balsam the work of K. Dieterich159 may be consulted.
The Sumatra benzoin is the most important of the commercial kinds for chocolate making. It is obtained from one of the Styracae, Styrax benzoin, and is a reddish grey mass in which separate tiers of resin are embedded. Benzoic acid and vanillin are the most important constituents. It is adulterated with Palembang benzoin, colophony, dammer, storax, and turpentine. Respecting the chemical investigation of commercial benzoin the above-mentioned work of K. Dieterich may also be referred to.
Benzoin is almost exclusively used for the preparation of chocolate varnish and sweets laquer, which are prepared by dissolving from 25 to 45 grammes of the laquer body in 100 grammes of strong spirit. The laquer body may contain varying quantities of benzoin and bleached shellac. The decorations of chocolate are painted with this laquer in order to give them a glistening appearance and greater durability.
The following colouring materials are permitted by the German law of the 14th May 1879 to be used for sugar goods and consequently also for chocolate and cacao preparations.
In the meantime a number of comparatively harmless aniline colours have been permitted in Austria for colouring sugar goods and liqueurs, and eventually also for cacao preparations.160 As in the author’s opinion there is no ground for objecting to their use in other countries, a list of them is given under their commercial and scientific designations.