Book 4
. Filsinger, the meritorious experimenter on the subject of cacao, has by König’s method determined the amount of crude fibre in a series of different varieties of cacao bean, and obtained the following results as regards shelled and roasted beans.
percent 1. Puerto Cabello 5·37 2. Java 3·97 3. Ariba Guayaquil I 4·10 4. Ariba Guayaquil II 4·07 5. Machala Guayaquil I 4·43 6. Para 4·01 7. Surinam Guiana 3·01 8. Bahia 2·81 9. Grenada 3·10 10. Guatemala 3·50 11. Machala Guayaquil II 3·58 12. Caracas 3·65 13. Samana 4·58 14. St. Thomé A I 4·13 15. St. Thomé A II 2·95 16. St. Thomé B 3·15 17. Haiti 3·12[76]
These new values may be provisionally regarded as normal. From 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: ————————————————————————+——————+——————+——————+——————+——————+——————- Insoluble respectively |Mara- |Cara- |Trini-|Mach- |Porto | Mean in dilute hydrochloric |caibo | cas | dad | ala | Cab- | or nitric acid | | | | | ello | ————————————————————————+——————+——————+——————+——————+——————+——————- 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 | | | | | | Soluble in dilute | | | | | | hydrochloric | | | | | | or nitric acid: | | | | | | 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 ———————————————+——————+—————+————-+————-+————-+————-+————-+————— |Amount| | | | | | | | 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
————————————————————-+————-+————-+————-+————-+————-+————-+————-+————— |Surin|Carac|Trini|P Cab|Mach |P a P|Ariba|Mean ————————————————————-+————-+————-+————-+————-+————-+————-+————-+————— | ~Per cent~ ————————————————————-+————-+————-+————-+————-+————-+————-+————-+————— Moisture |13·02|11·90|13·09|12·04| — | — | — |12·51 Fat | 4·17| 4·15| 4·74| 4·00| — | — | — | 4·23 Cacao tannic acid | | | | | | | | soluble in 80% | | | | | | | | 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 Proportion of husk | | | | | | | | 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].
==========================+========+=======+=======+========+======== | Mara- | Cara- | Trini-|Machala | Porta | caibo | cas | dad |Guayaquil| Plata +————————+———————+———————+————————+———————— | ~Per cent~ ==========================+========+=======+=======+========+======== Ash dried at 100° C. | | | | | | | | | | I. insoluble in dilute | | | | | hydrochloric | | | | | or nitric acid: | | | | | 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 | | | | | II. Soluble in dilute | | | | | hydrochloric | | | | | or nitric acid: | | | | | 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 to chlorine | | | | |
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,