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.
d) Cinnamon.
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.
e) Cloves.
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.
f) Nutmeg and Mace.
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.
g) Cardamoms.
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.
IV. Other Ingredients.
a) Ether oils.
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:
1. Cinnamon oil,
2. Clove oil,
3. Cardamom oil,
4. Coriander oil,
5. Nutmeg oil (ethereal),
6. Mace oil (ethereal).
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.
II. ~Peru balsam and Gum benzoin.~
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 percent) 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.
Dieterich[159] 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.
V. Colouring materials.
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.
~White~: finest flour starch.
~Yellow~: saffron, safflower, turmeric.
~Blue~: litmus, indigo solution.
~Green~: spinach juice as well as mixtures of the permitted blue
and yellow colours.
~Red~: carmine, cochineal, madder red.
~Violet~: mixtures of the harmless blue and red colours.
~Brown~: burnt sugar, licorice juice.
~Black~: chinese ink.
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.
=Red=: ~Fuchsin~ = Rosaniline hydrochloride, soluble in water and
alcohol.
~Acid Fuchsin~ or ~Fuchsin S~ or Rubin = Sodium or calcium
acid salt of rosaniline disulphonic acid, soluble in water.
~Rocellin~ or ~Roscellin~ (Fast Red) = Sulpho
oxyazonaphtalin, soluble in water.
~Bordeaux~ and ~Ponceau red~ = product of the combination of
β naphtol-disulphonic acid with diazo-compounds of Xylol and higher
homologues of benzol, soluble in water.
~Eosin~ = Tetrabrom-fluoresceïn, soluble in water and alcohol.
~Phloxin~ = Tetrabromo-dichlor-fluoresceïn, soluble in water.
~Erythrosin~ = Tetra iodio-fluoresceïn, soluble in water.
=Blue=: ~Alizarin blue~ = Dioxyanthraquinone-quinoline, slightly
soluble in alcohol.
~Aniline blue~ = Triplienylrosaniline, soluble in alcohol.
~Water blue~ = Triphenylrosaniline, sulphonic acid soluble in
water.
~Induline~ = Azodiphenyl blue sulphonic acid and its derivatives,
soluble in alcohol.
=Yellow=: ~Acid yellow R~ or ~fast yellow R~ = Sodium
amidoazobenzol-sulphonate, soluble in water.
~Tropaedlin~ 000 or ~Orange~ I = Sulphoazobenzoll [Greek:
alpha]-naphthol, soluble in water.
~Naphtholyellow~ = Sodium salt of dinitro-α-naphthol sulphonic
acid, soluble in water.
=Violet=: ~Methylviolet~ = Hexa-and penta-methylpara-rosaniline
hydrochloride, soluble in water and alcohol.
=Green=: ~Malachite green~ = Tetramethyl-diamidotriphenyl-carbinol
hydrochloride, soluble in water and alcohol.
The above, as well as the following colours: (blue) amaranth, brilliant
blue and indigosulfone, (red) erythrosin, also acid yellow S, orange
L and light green S F, have in the meantime been accepted by the
American Foods Act as perfectly harmless for colouring any and all
articles of food.[161]
For some time past E. Merck of Darmstadt has supplied a perfectly
harmless green colouring material under the name of chlorophyll, in
alcoholic and in water solutions, as well as technical chlorophyll, for
colouring oils and fats, which is the unaltered leaf green and is the
best green colouring agent for articles of food and therefore for cacao
preparations.
The chlorophyll which is soluble in fat has also been recommended like
some of the aniline colours which are soluble in fat, as for example:
Indulin 6 B (blue), Sudan yellow G, Sudan III (red), and Gallocyanin
(violet) for colouring cacao butter; but in regard at least to the
aniline colours mentioned, no authoritative sanction for their use has
yet been given.
FOOTNOTES:
[136] Flour can be more easily blended than starch with the cacao mass,
as the granules of starch are only with difficulty crushed.
[137] Recently in some inferior kinds of cocoa powder a quantity
of oatmeal has often been added (up to 5 percent), causing the
preparation to thicken when it is boiled with water.
[138] Still better, as less productive of dust, there being a
less rapid circulation of air, and also not so wasteful, are the
dismembrators as built by Paul Franke & Co.
[139] Chemiker-Zeitung 1899. Repert. No. 38, p. 372.
[140] Chemiker-Zeitung 1889, p. 408.
[141] Beckurts Annual Report of Pharmaceutical Progress etc. 1888, p.
307.
[142] See Möller p. 114.
[143] Die Nahrungs-und Genußmittel aus dem Pflanzenreiche p. 140.
[144] This consists of 15 parts of defatted cacao, 200 parts of
arrowroot 50 parts of salep and fifty parts of vanilla-sugar.
[145] Krupps Iron Works supply the latest constructions, strongly to be
recommended.
[146] Arbeiten des kaiserl. Gesundheitsamtes Vol. 15 p. 1-113 and
Zeits. f. d. Untersuch. von Nahrungs-und Genußmitteln Vol. 3 21.-25.
January.
[147] Der Tropenpflanzer 1898, p. 24.
[148] Journal of the Society of Arts 1897, Vol. 46, p. 39-40.
[149] Compare Gieseler, Vanillevergiftungen, Bonn 1896; Arning
(Deutsch. med. Wochenschrift 1897, pag. 435) and Guerin (Annales
d’occulistique, 1895 4. October).
[150] Arbeiten aus dem Kaiserl. Gesundheitsamte 1899.
[151] Journal of the American Chem. Society 1899, Vol. 21, p. 719 and
Chem. Ztg. Rep. 1899, p. 275.
[152] Berichte der Deutschen Chemischen Gesellschaft Vol. VII, p. 698
and Friedländer, Fortsch. der Theefarbenfabrikation, Berlin 1888, p.
583 and elsewhere.
[153] L’état actuel de l’industrie de la parfumerie en France. Revue
Générale des sciences pures et appliquées, Paris 1897, p. 663.
[154] Chem. Zeit. Repert. 1898, p. 181.
[155] Pharm. Zeit. 1888, p. 634 and Pharm. Centralhalle 1898, p. 673.
[156] Zeitschr. für angewandte Chemie 1899, p. 428.
[157] Pharmaceutische Centralhalle 1898, p. 357.
[158] Berlin 1899, Jul. Sprenger, page 53 et seq.
[159] K. Dieterich, Die Analyse der Harze, Balsame und Gummiharze,
Berlin 1900, page 76.
[160] Regulation of 22 and January 1896.
[161] See also Farbenzeitung 1909, vol. XV, pages 301, 348, 392 and 436.
+Part IV.+
Examination and Analysis of Cacao Preparations.
A. Chemical and microscopical examination of cacao and cacao
preparations.
The following observations will serve as an introduction to the
chemical and microscopical examination of cacao preparations calculated
to be of special value to the food chemist, corresponding as they do
to the state of scientific progress at the present day and special
attention being paid to the critical treatment of the methods of
analysis etc. adopted.
a) Testing.
This is a point of great importance, inasmuch as it directly influences
the result of the analysis of cacao goods. This is especially the
case when dealing with ~cocoa powders~, as the test is liable
to vary considerably according to the amount of moisture contained
in the preparation and the degree of fineness of the powder. In the
case of cocoa powders, the sample should be taken repeatedly from a
large supply, and from all parts of the material to ensure getting
an average sample. The samples taken should be of uniform volume and
should, before proceeding to apply the test, be closely mixed together,
being, if possible, first passed through a fine sieve. The material
ready for the following experiments should then be placed in tin, or
better still, glass receptacles with well-fitting corks or stoppers.
Paper wrappings or cardboard-boxes are not to be recommended, as the
powder is apt to become drier or moister according to the state of the
atmosphere to which the packets are exposed.
The most suitable quantity for experimental purposes is, in the case
of both chocolate and cocoa powder, as well as butter and covering
material, 100 kilogrammes. When determining the amount of foreign fat
in cacao preparations, however, as well as estimating the ash content
of powder, up to 250 kilogrammes of sample material can be used. In
Germany the regulations of the Commercial Agencies of the government
public food chemists obtain when sampling and analysing cacao
preparations.[162]
b) Chemical Analyses.
The analyses of all cacao preparations from a chemical point of
view are conducted, almost without exception, with the object of
determining the values for ~moisture~—~mineral matter~
(estimation of the amount of the carbonic acid alkalis and the silicic
acid)—~fat~ (estimation of foreign fat)—~theobromine~
and ~coffeine~—~sugar~—~starch~ (foreign
starches)—~albuminous matter~ and ~raw fibre~. The last
regulation may also be extended to the estimation of the quantity of
shell present.
1. ~Estimation of moisture.~ 5 grammes of material (i. e.
fine-crushed chocolate mass) are left to dry (if possible in a
double-walled glycerine drying chamber) for about 6 hours at a
temperature of 105 Deg. C., the loss of weight of the material being
estimated as moisture. The drying should not be continued longer than
6 hours, as fatty material is liable after the expiration of this time
to recover some of its weight, owing to the oxygen of the air entering
into chemical combination with the fat which rises to the surface or
detaches itself from the material. When analysing chocolate, great
care should be taken to prevent the mass from melting down and running
together at one point. If this occurs, the following treatment must be
adopted: A shallow watch-glass is filled with about 10 grammes of sand,
well washed and dried, a very fine sand such as so-called sea-sand
being preferable to others, the glass then transferred to the drying
closet, cooled, and finally 5 grammes of the fine-crushed chocolate
added. The mixture is then deposited for a period of 6 hours in the
drying chamber, at a temperature of 105 Deg. as indicated above and the
weight of the sand deducted when finally calculating the value of the
moisture.
If as low a quantity as 5 percent of gelatine has been added to
the chocolate, as much as 10 percent of water can be added without
in any way affecting the appearance of the material, although such a
proceeding is exceedingly detrimental to the taste and durability of
the preparation. Such chocolates usually have a dull surface and, if
stored in a warm place, are apt to break up and become paler in colour;
this result can, however, be prevented by an extra addition of fat. Too
high a[163] fat content points in any case of additions of gelatine. P.
Onfroy[164] determines the addition of gelatine by boiling 5 grammes
of chocolate chips in 50 cubic centimetres of water, adding 5 cubic
centimetres of a solution containing 10 percent of lead acetate, and
then filtering the whole. If gelatine is present in the chocolate, the
liquid, on a few drops of saturated picric acid being added, leaves
a yellow, amorphous sediment. If the addition of gelatine is very
trifling, the gelatine is held in check or neutralised by the tannic
acid. The defatting is then effected by ether and the chocolate stirred
up with 100 cubic centimetres of hot water. 5-10 cubic centimetres of
a solution of lye containing 10 percent of alkali and about 10 cubic
centimetres of the above-mentioned lead acetate solution are added.
The compound of gelatine and tannic acid is soluble in the hydrate of
the alkali, and is afterwards re-deposited by the action of the lead
acetate, so that it can easily be detected by means of picric acid in
the neutralised filtrate. As picric acid is incapable of effecting the
deposition of the theobromine, the deposition observed can only be
caused by the presence of gelatine.
Like gelatine and glue, the addition of a quantity of adraganth has
the power of binding the moisture and saving the fat. A method of
estimating the quality of this vegetable gum, of which at the most 2
percent should be present, has recently been described by Welmans;
this method is explained on page ... in the microscopic section.
2. ~Estimation of ash~[165]: 5 grammes of material are heated
in a platinum vessel, pan or flat tray, the latter or other similar
shallow receptacle being the most suitable, holding from 25 to 30 cubic
centimetres. Care should be taken when heating that the extremity of
the Bunsen flame only touches the bottom of the vessel. The resulting
gases are then ignited, and the ~completely~ charred mass pressed
or stirred to a powder by means of a platinum wire or rod hammered
flat at the end; the pan should be frequently made to revolve and its
contents continually stirred during heating, care being taken, too, to
hold it slanting the whole time. The pan should be held in this way
over a moderate flame until the ash assumes almost a white colour.
As soon as this occurs, the pan should be cooled down and the ash
uniformly saturated with a concentrated watery solution of carbonate of
ammonia, whereon the vessel is placed in the drying chamber and dried
at a temperature of 100 Deg. C. The contents of the pan are then heated
again very cautiously over the Bunsen flame, care being taken that the
bottom of the vessel is only allowed to become red-hot very gradually
and to remain so for a very short time; the pan is then covered up and
transferred to the dessicator to be cooled, and, on the completion of
this process, its weight determined.
After repeating the saturating process with the solution of carbonate
of ammonia, drying and heating for a short time as previously
described, the accuracy of the weight first obtained is again tested.