These new values may be provisionally regarded as normal. Fr_The Manufacture of Chocolate and other Cacao Preparations

these results not only can an idea of the functioning of the cacao

shelling machine be obtained, but also the presence of any occasional

admixture of husk in cacao preparations may be inferred, since the husk

contains a great deal more crude fibre than the kernel. Therefore the

determination of the crude fibre is an important item in the testing of

cacao preparations, as there is no doubt that the presence of vegetable

substances rich in crude fibre can be detected by the increase in the

amount of cellulose.

8. ~Sugar and plant acids.~

The presence of glucose in raw cacao beans was first pointed out

by Schweitzer[77]. The sugar is formed by the action of the cacao

ferment on the glucoside cacaonin during the processes of drying and

fermentation. In addition to sugar, malic and tartaric acids have been

observed. These substances, however, are only of interest to the plant

physiologist and not to the manufacturer, so it is sufficient merely to

notice them here in passing.

9. ~The mineral or ash constituents.~

When cacao beans are ignited, the constituents of an organic nature are

volatilised and only the non-volatile or inorganic constituents remain

behind. These consist of potash, soda, lime, iron magnesia, combined

with silicic acid, phosphoric acid, sulphuric acid and chlorine.

The amount of ash in raw and shelled cacao beans varies from 3-4 %.

Tuchen[78] found 2·9-3 %, Trojanowski[79] 2·08-3·93 %, Zipperer[80]

2·7-4 %, L’Hote[81] 2·2-4 %, H. Beckurts[82] 2·20-3·75, J. Hockauf[83]

2·84-4·4 percent. Of those kinds which are now most in use, Ceylon

gave 3·30 percent, Java 3·20 and Kameroon 2·95 percent. (Beckurts).

Quantitative analyses of the ash of the cacao beans have been made by

several investigators, and the following table gives a series of the

most complete analyses, made by R. Bensemann[84].

~Table~ 14. =Analysis of the ash of Cacao Beans by R. Bensemann.=

The ash of the kernel free from husk dried at 100°C. contained:

————————————————————————+——————+——————+——————+——————+——————+——————-

in dilute hydrochloric |caibo | cas | dad | ala | Cab- |

————————————————————————+——————+——————+——————+——————+——————+——————-

a) Volatile dessicated | 0·142| 0·076| 0·144| 0·074| 0·198| 0·127

at 100° C. | | | | | |

b) Fixed at red heat | 0·312| 1·663| 0·553| 0·630| 1·075| 0·846

| | | | | |

c) Potassium oxide |35·889|33·844|30·845|30·686|29·989|32·251

K_{2}O | | | | | |

d) Sodium oxide | 0·515| 0·766| 1·964| 4·173| 3·427| 2·169

Na_{2}O | | | | | |

e) Calcium oxide CaO | 4·118| 5·030| 4·638| 3·112| 2·923| 3·964

f) Magnesium oxide MgO |15·750|15·151|16·060|16·172|17·562|16·139

g) Ferric oxide | 0·182| 0·217| 0·491| 0·629| 0·303| 0·364

Fe_{2}O_{3} | | | | | |

h) Aluminium oxide | 0·080| 0·326| 0·490| 0·432| 0·305| 0·327

Al_{2}O_{3} | | | | | |

i) Silicic acid | 0·214| 0·211| 0·169| 0·134| 0·240| 0·194

SiO_{2} | | | | | |

k) Phosphoric anhydride|27·741|29·302|28·624|37·000|35·274|31·588

P_{2}O_{5} | | | | | |

l) Sulphuric anhydride | 2·632| 2·740| 3·957| 2·042| 3·952| 3·065

SO_{3} | | | | | |

m) Chlorine Cl | 0·295| 0·341| 0·427| 0·279| 0·085| 0·285

n) Carbonic anhydride |10·349| 8·435| 8·953| 2·788| 3·481| 6·801

CO_{2} | | | | | |

o) Water H_{2}O | 1·847| 1·975| 2·781| 1·912| 1·205| 1·944

Oxygen O equivalent | 0·066| 0·077| 0·090| 0·063| 0·019| 0·064

to chlorine

In previously describing the aleuron granules of the cacao bean it was

mentioned that they contain a comparatively large globoid. According

to Molisch[85], when sections are cautiously heated on platinum foil,

these globules are found in the ash. From their number they give a

characteristic appearance to the ash of cacao beans, and thus may serve

as a good means of identifying cacao, since they can be detected in the

smallest quantity of a genuine cacao preparation.

A noteworthy fact may here be mentioned, namely the presence of a

rather small amount of copper in the ash of cacao beans as well as

the husks. Duclaux[86] was the first to point out this fact, which

several other observers, such as Skalweit[87] and Galippe[88] have also

confirmed. The amount of copper in the husk varies from 0·02 to 0·025

percent and in the beans from 0·0009-0·004 percent (Duclaux). Copper

in similar amount is found in all kinds of beans and husks, and its

presence is due to the absorption of copper by the plant from the soil,

whence it gradually accumulates in the fruit.

b) The Cacao Shells.

Most of the constituents which exist in the cacao kernels are also to

be found in the husks and the methods for isolating and determining

them are the same in both cases. The composition of the husk, according

to Laube and Aldendorff[89], is as follows:

~Table~ 15.

Key to Row 1:

Col 4A = Nitrogenous substance

Col 6B = Non nitrogenous extractive

———————————————+——————+—————+————-+————-+————-+————-+————-+—————

| of | | | | |Woody| |

|husk |Water| 4A | Fat | 6B |fibre| Ash | Sand

———————————————+——————+—————+————-+————-+————-+————-+————-+—————

| ~Per cent~

———————————————+——————+—————+————-+————-+————-+————-+————-+—————

Caracas | 20·09| 7·74|11·68| 5·99|35·29|12·79| 8·32|18·62

Guayaquil | — | 9·11|12·94|10·75|47·08|13·12| 6·79| 0·21

Trinidad | 14·04| 8·30|15·14| 4·23|46·05|18·00| 7·06| 0·92

Puerto Cabello | 14·92| 6·40|13·75| 4·38|47·12|14·83| 6·06| 7·46

Soconusco | 18·58| 6·48|19·12| 6·48|39·39|15·67| 8·15| 4·71

Mean | 16·33| 7·83|14·29| 6·38|45·79|14·69| 7·12| 5·90

~Zipperer’s analysis[90] of the unroasted husks gave the following

results~:

~Table~ 16.

Key to Row 1 abbreviations:

Col 2 = Surinam = Surin

Col 3 = Caracas = Carac

Col 4 = Trinidad = Trini

Col 5 = Puerto Cabello = P Cab

Col 6 = Machala = Mach

Col 7 = Port au Prince = P a P

————————————————————-+————-+————-+————-+————-+————-+————-+————-+—————

————————————————————-+————-+————-+————-+————-+————-+————-+————-+—————

| ~Per cent~

————————————————————-+————-+————-+————-+————-+————-+————-+————-+—————

Moisture |13·02|11·90|13·09|12·04| — | — | — |12·51

Fat | 4·17| 4·15| 4·74| 4·00| — | — | — | 4·23

alcohol | 5·10| 3·80| 4·87| 9·15| — | — | — | 4·58

Theobromine | 0·33| 0·30| 0·40| 0·32| — | — | — | 0·33

Ash | 7·31|16·73| 7·78| 8·99| — | — | — |10·20

Woody fibre |14·85|17·99|18·04|15·98| — | — | — |16·71

Nitrogen | — | 2·25| 2·13| — | — | — | — | 2·19

in the raw seeds |14·60|15·00|14·68|12·28|16·14|16·00|18·68|15·34

Roasted cacao husks contain according to G. Paris[91] the following

constituents:

Moisture 12·57 percent, nitrogenous substance 14·69 percent, fat 3·3

percent, extractives 45·76 percent, crude fibre 16·33 percent and ash

7·35 percent.

50 grammes of the husks when boiled with 500 grammes of water give

25·08 percent extract, 20·68 % organic substance, 4·4 % ash, 0·21 %

sugar (reducing substance), 0·79 % theobromine, 0·12 % percent acid,

calculated as tartaric acid.

The following constituents have been found by R. Bensemann[92] in the

ash of cacao husks:

~Table~ 17[93].

==========================+========+=======+=======+========+========

+————————+———————+———————+————————+————————

| ~Per cent~

==========================+========+=======+=======+========+========

| | | | |

a) Volatile dessicated at | 0·113 0·421 | 0·979 | 0·306 | 1·247

100° C. | | | | |

b) Fixed at red heat | 1·917 |47·711 |29·315 | 37·662 | 51·513

| | | | |

c) Potassium oxide K_{2}O | 31·517 |11·812 |25·866 | 23·117 | 12·174

d) Sodium oxide Na_{2}O | 4·188 | 3·298 | 2·726 | 1·210 | 2·780

e) Calcium oxide CaO | 10·134 | 4·458 | 5·097 | 3·503 | 4·401

f) Magnesium oxide MgO | 9·546 | 4·703 | 5·206 | 4·837 | 4·090

g) Ferric oxide | 0·647 | 0·931 | 0·339 | 0·958 | 0·462

Fe_{2}O_{3} | | | | |

h) Aluminium oxide | ·281 | 1·554 | 0·710 | 1·854 | 1·046

Al_{2}O_{3} | | | | |

i) Silicic acid SiO_{2} | 1·180 | 7·975 | 2·416 | 4·321 | 6·780

k) Phosphoric anhydride | 9·068 | 7·630 | 4·703 | 7·288 | 7·242

P_{2}O_{5} | | | | |

l) Sulphuric anhydride | 3·041 | 1·478 | 3·398 | 1·741 | 2·012

SO_{3} | | | | |

m) Chlorine Cl | 1·005 | 0·220 | 1·022 | 0·255 | 0·444

n) Carbonic anhydride | 25·454 | 5·399 |16·290 | 11·834 | 4·247

CO_{2} | | | | |

o) Water H_{2}O | 2·135 | 2·499 | 2·263 | 1·171 | 1·662

p) Oxygen O equivalent | 0·226 | 0·049 | 0·290 | 0·057 | 0·100

As evidenced in the preceding examples, data as to the constituents of

the cacao husk deviate considerably with different authors. Laube and

Aldendorff, for instance, found 14-20 percent, while Zipperer obtained

12-18 percent of husks.

These discrepancies are mainly due to adhering sand and ferruginous

earth collected during the drying and fermenting processes. If the

beans are carefully collected and kept free from earthy substances, the

percentage of husks as against that of the bean will appear much lower;

it is, indeed, now possible to obtain properly treated beans which

contain on an average only some 10 percent of husks, such as Ariba

and Machala. The husks of these two varieties are exceedingly woody,

and their amount sometimes reaches 15 percent. The latest machinery

for cleaning the beans effects so complete a separation of the husks

from the kernel that very little of the former remains in the finished

cacao preparation (less than 1 percent in thin-shelled beans and no

more than 2 percent in thick-shelled beans such as Ariba). For some

years it was not possible to effect so thorough a removal of the husk,

so that there was always found an appreciably large amount of shells

in the finished preparations, which rendered it difficult to detect

adulteration. As, however, the quantity of ash present in the husk is

double that in the kernel, it was possible to form an opinion as to

the intentional admixture of shells from the increase of ash in cacao

preparations. Hence the ash was always required to be determined when

adulteration was suspected. Under existing conditions the addition of a

quantity of shells sufficient to increase the percentage of ash present

in the powder or chocolate is scarcely practicable, so that, for the

purpose of detecting small additions, other methods must be resorted

to, such as the estimation of the crude fibre or silica in the ash[94]

with the aid of the microscope, in which it is possible to easily

distinguish the forms of the cotyledon (kernel) mass and those of the

husk. The diagram on page 14, Fig. 3, clearly shows the elementary

forms of the cacao husk as represented by Mitscherlich. It illustrates

a longitudinal section of the husk of Bahia beans, enlarged about

500 times, with six different cell elements in alphabetical order.

First the compressed cells of the epidermis are to be seen on the

exterior, in several parallel series and succeeded by moderately broad

and thin-walled cellular tissue of the parenchyma, which sometimes

presents large empty spaces (sch) the results of the loosening of the

cell walls through the formation of mucilage. This cellular tissue

(lp) is also permeated by bundles of spiral vessels (gfb), which, with

the dry cells, are characteristic of the husk, as they exist only in

very small quantity in the kernel. Then follow parallel rows of cells

(lp) resembling epithelial cells; next comes a layer of cells with

thick walls, the dry cells (st) and finally several rows of elongated

ones (lp). The silver membrane (is) interposes between the husk and

the kernel, fragments of which remain adhering to the shell after

separation of the latter.

To conclude, we find that the husk of the cacao bean consists of the

inner coat of fruit, called endocarp and other parts of the fruit

covering, as well as the skin of the seed[95]. The following layers

may be distinguished;

1. The pulp, (f in fig. 3) fragile large cells with frequent hiatus;

2. the ~endocarp~ (fe), a single layer of fragile, very narrow

and irregularly arranged cells, but ~without hiatus~;

3. the ~epicarp~, or skin (se), polygonal and extended cells,

with an outer wall of some thickness.

4. the ~parenchyma~ or cellular tissue (lp), consisting of

large and multiform cells, with vascular bundles (gfb), the large

mucilagenous or slime cells (sch) and

5. the ~sklerogenous or dry cells~ (st), a single layer of

vessels shaped like a horseshoe, and thickening towards the interior,

and in conclusion

6. the ~silver membrane~ (is), belonging to the earlier inner

coat of fruit, and consisting of two single rows of fat-bearing cells.

In examination of the husks of the plane surface enlarged 160 times

(fig. 8), it will be noticed that the characteristic epidermis (ep)

consists of large and rather elongated but irregular polygonal cells.

Frequently on the epidermis may be remarked a delicate network of

the cells constituting the fruit pulp (p). Beneath the epidermis

lies a very delicate transverse cellular layer (qu) followed by the

parenchyma, as already stated. The remaining elementary forms are

not readily observed on a plane surface but only in section, though

we adjoin a few diagrams, showing the layers as isolated from the

pericarp; namely, fig. 9 parenchyma, a layer of sklerogenous cells,

fig. 10, and the silver membrane (is) with two superjacent Mitscherlich

particles (tr) in fig. 11.

[Illustration: Fig. 8.]

[Illustration: Fig. 9.]

[Illustration: Fig. 10.]

For microscopical examination, the husk must first be defatted with

petroleum or ordinary ether and then treated with dilute chloral

hydrate (8: 5) to assist the definition of the forms. An approximate

estimation of the amount of husk in a cacao preparation can be made by

means of the microscope, adopting Filsinger’s[96] levigation method,

which consists of concentrating those elements of the cacao which are

seldom seen even in suspension in water, and which sink to the bottom

when repeatedly stirred in that liquid. To these belongs first of all

the husk, and its presence and determination in the levigation method

is accordingly greatly facilitated. The details of the method will be

further described in treating of husk admixtures in cacao preparations.

[Illustration: Fig. 11.]

Cacao shells are the only by-product in the cacao industry, and have

been developed and exploited to such an extent, that a rational

utilisation of the ever increasing quantities has become a matter of

urgent necessity. They are not used in our industry, for an admixture

of husk is not permissible, even in the inferior kinds of chocolate

or cocoa powder, but must be regarded as an adulteration. It is true

that they have been brought on the market as cocoa tea, and again,

have been coated with sugar, to make them tasty; and to this day,

candied husks constitute a favourite sweetmeat of the population of

East Germany. But in this way only comparatively inferior quantities of

the by-product were absorbed, and consequently projects of all kinds

have been suggested to use up larger percentage. As we have seen, the

fatty contents of the bean can be extracted with benzine, and there

is a resultant 4 or 5 percentage of fat of inferior value, which is

commercially known as “Dutch IIa Cacao Butter”; the defatted shells can

be further used for the preparation of theobromine, as Zipperer has

already noted in the first edition of this book.

Kathreiner’s successors in Munich[97] employ an extract of cacao

shells prepared with hot water, in order to improve coffee berries

during the roasting and to give a flavour to the coffee substitutes

prepared from corn and malt. Cacao extract is also prepared from the

shells[98] by first treating them with water or steam, and afterwards

extracting with water, and finally evaporating as far as necessary. The

thick extract thus prepared contains theobromine, and is intended for

use either alone or as an addition to cacao powder and chocolate.

Strohschein in Berlin[99] prepares from the shells a thick liquid

extract which he calls “Martol Its preparation was suggested by the

fact that the cacao husk gives evidence of containing a considerable

amount of iron. In “Martol”, the iron occurs as a tannate, and the

preparation further contains theobromine, carbohydrates, and phosphoric

acid. The preparation is said to be used as a medicinal remedy in

chlorosis, yet has scarcely justified such a statement.

Alfred Michel of Eilenberg[100] utilises the shells in the preparation

of a brown colouring material. The husks, free from impurities, are

first soaked in soft water, with or without the addition of sulphuric

acid, then washed and finally treated with a strong 35 % solution of

caustic soda. From the alkaline solution, the colouring matter is

precipitated with acid or acid metallic salt, collected on a filter,

and again washed. Thus obtained, it is a dark reddish-brown paste,

possessed of a vitreous fracture. The yield of colouring matter is from

20-25 % of the weight of the original shells. By re-treatment with

alkali, the paste can be again obtained in solution and can be used

as required, either in liquid or paste form. The colouring matter can

be obtained in different tints, either by soaking the shells in more

er less dilute sulphuric acid, or by precipitation from the alkaline

solution at various temperatures, or yet again, by the addition of

metallic oxides.

Boussignault[101] says that in Paris briquettes have been made from

cacao shells, and twenty-two years ago, Zipperer[102] proposed to

use them as fodder, especially for horses. Experimental work in that

direction was instituted, but for various reasons, had to be abandoned.

The question as to a rational working up of the husk of the cacao bean

is once more receiving special consideration, more particularly since

the publication by the “Association of German Chocolate Manufacturers”

of a prize essay on the subject. The fodder value of the husks as

determined by Märcker is apparent from the following figures:

~Table~ 18.

===========================+=============+===========+===========

| free from | | whole and

Shells | dust, whole | fine meal | dusty

| % | % | %

===========================+=============+===========+===========

Moisture | 9·08 | 6·50 | 9·95

Albumen | 13·56 | 14·13 | 12·69

“ digestible | 6·06 | 7·07 | 4·38

Fat | 2·65 | 6·76 | 3·96

Raw fibre | 29·14 | 25·80 | 21·55

Ash | 6·32 | 6·44 | 7·26

Non-nitrogenous extractive | 39·25 | 40·37 | 44·59

Feeding experiments which were carried out in certain agricultural

institutes showed that the cacao husk stands in nutritive value

between good meadow hay and wheaten bran, and is not only a fattening

fodder for oxen, but also a valuable feeding material for cows and

deer[103]. These results have been confirmed by Prof. Feruccio Faelli

in Turin[104].

The advantages of cacao shells as fodder, when a comparison with bran

is established, are at once apparent. Two hundredweight (that is to

say, about 220 lbs. averdupois) cost only from six to seven shillings,

whilst the price of bran varies between nine and ten shillings. The

husks also keep better, for after having been stored eighteen months,

Professor Faelli found that they had undergone no alteration, whilst on

the other hand bran had become sour. A further advantage possessed by

the husk is that it will absorb four times its weight of water against

three times absorbed by bran. Cattle not only readily get accustomed

to the fodder but subsequently take to it with eagerness. The best

results were obtained with Dutch, Swiss and Parmesan milch cows. After

10 days feeding the butter and milk-sugar had increased, as well as the

daily average yield of milk from 44 to 49·5 kilogrammes. As soon as the

feeding with cacao husk was discontinued the yield of milk decreased.

Faelli concludes that cacao husk, which can be used as a fodder up to 4

kilog. daily, exercises a very favourable influence on milch cows, and

he purposes to continue the investigation with horses.

In a report on the Experimental Farms of Canada 1898, page 151,

reference is made to the manurial value of the husks in enriching the

soil with nitrogen and potash, a fact which had already been pointed

out by Boussignault.

The future use of the husks appears therefore to be ensured, and it

is to be hoped that it will allow of a permanent consumption of this

by-product.

FOOTNOTES:

[1] Of which the Central Province has 32,003 acres: North Western

Province 3689 acres, North Central Province 25 acres, Province of Uva

2153 acres and Province of Sabaragamura 1918 acres. (From information

kindly furnished in a letter of W. Freudenberg jun. German Consul at

Colombo.)

[2] See references at the end of this book.

[3] Pronounced Chocolatl.

[4] Revue des sciences pures et appliquées 1899, No. 4, page 127.

[5] Vol. 7, Part 2: Diseases and Parasites of the Cacao Tree. With

special reference to the conditions obtaining in the colonies belonging

to Germany. By Dr. F. C. Faber, Berlin 1909, Parey & Springer.

[6] Recently so-called fermenting-houses, as recommended by L. Kindt.

(Cf. Kultur d. Kakaobaues und seine Schädlinge, Hambourg 1904), have

answered very well. Yet the chemismus of fermentation is by no means

sufficiently explained, and quantitatively and qualitatively, there is

a lack of completeness in the analyses bearing on the process.

[7] Special ovens (System Mayfarth) are also used, and sometimes

complete heating and drying installations.

[8] This had already been noticed by J. Hinchley Hart; Cacao (Trinidad

1892). It is therefore scarcely conceivable that the “Germination”

theory should have held the field so long.

[9] According to Schweizer (Pharmazeut. Ztg. 1898, page 389)

these substances would be represented by the chemical formula

C_{60}H_{86}O_{15}N_{4}, corresponding to 1 molecule cacao red, 6

molecules grape sugar, and 1 molecule Theobromin.

[10] Cf. Hilger, Apotheker-Ztg. 1892, p. 469.

[11] Cf. Tropenpflanzer V. 4, 1901, April-Number.

[12] Loc. cit. page 167.

[13] The leaves of the tobacco plant must also be fermented, before

they acquire their rich brown colour and peculiar aroma.

[14] Reports of the German Pharmaceutical Society 1900, Vol. 5, page

115.

[15] J. F. Hanousek, Die Nahrungs-und Genußmittel aus dem

Pflanzenreiche. p. 437.

[16] Anleitung zur mikroskopischen Untersuchung der Nahrungs-und

Genußmittel. Jena 1886.

[17] Grundriß einer Histochemie der pflanzlichen Genussmittel.

[18] See page 16 loc. cit.

[19] Cf. Dr. Stollwerck. The Cacao and Chocolate Industries.

[20] Mitscherlich, p. 57.

[21] Cacao and its Preparation; a few Experiments.

[22] Ridenour, M. American Journal of Pharmacy, 1895. Vol. 67, p. 207.

[23] Filsinger, Chemical Journal, 1887, p. 202.

[24] Z. U. N. G., 1906. Vol. 12, p. 88 et seq.

[25] The husks contain no fat when in a fresh condition but absorb fat

from the bean when the cacao is fermented and dried; especially so also

in the later process of roasting, when they become saturated with it.

[26] Klimont, Ber. d. Dtsch. chem. Ges. 34, 2636; Monatssch. f. Chem.

1902 (23) 51; 1904 (25) 929; 1905 (26) 536.

[27] Journal of the Society of Chemical Industry 1899, p. 556.

[28] Chevalier & Baudrimont, Dictionnaire des alterations.

[29] Achiv de Pharmacie 1888, Vol. 26, p. 830.

[30] See previous reference.

[31] Schmidt, Ztschr. analyt. Chem. 1898, vol. 301 p. 301; cf. also P.

Welmans, Pharm. Ztg. 1894, p. 776.

[32] Pharm. Zeitung 1898 No. 10.

[33] Cor. Assoc. Germ. Choc. Man. 1889, Vol. 5, p. 65.

[34] The Brit. and Colon. Druggist 1897 No. 21.

[35] Zeitschr. anal. Chemie.

These new values may be provisionally regarded as normal. From