October, 1908.] 



341 



Edible Products. 



The internal fermentation shows as 

 follows :— So long as the seed remains 

 alive, no chemical process seems to take 

 place, but, as soon as dead, such process 

 sets in. The temperature developed by 

 the fermentation of the pulp causes the 

 deatli of the contents of the kernel. 



He made the following experiments to 

 establish the temperature at which 

 death took place. To secure for the ex- 

 periments well germinating and uniform 

 seeds special care was taken. Ten seeds 

 were exposed for three hours to a tem- 

 perature of 43° 0., all germinated. After 

 an exposure lasting six hours four ger- 

 minated but with unhealthy looking 

 sprouts. When exposed nine hours one 

 germinated. Of ten seeds which were 

 exposed for six hours to a 44° C. tem- 

 perature none germinated. 



As the temperature usually developed 

 during the external fermentation reaches 

 45° 0. and is continued for at least four 

 days, it is fairly certain that all the 

 seed-germs are killed and the internal 

 fermentation has set in. 



The next, investigate the change of 

 colour taking place in the kernels. The 

 change from purple in the unfermented 

 bean to brown in the fermented appears 

 to be the result of some agent or agency 

 present in the kernel itself, as no direct 

 connection seems to exist between the 

 two (external and internal) fermenta- 

 tions. This agent is an enzyme, and a 

 series of experiments are conducted to 

 prove this assertion. A comprehensive 

 understanding of the subject can be 

 gained by noting the result of these ex- 

 periments without going into detailed 

 descriptions of them. 



If kernels are finely pulverized the 

 change of colour takes place, free access 

 of air being essential. 



If the kernels are previously steeped 

 in boiling water no colour-change occurs. 



If to the steeped mass some unsteeped 

 kernels are added the colour changes. 



The enzyme manifests the greatest 

 activity at a temperature ranging from 

 45°0. to 60°C. (optimum temperature). 



Through the usual method of washing, 

 filtration and alcoholic precipitation a 

 culture of the enzyme was made. Prom 

 one kilo of beans about one-half gram of 

 culture was obtained. 



When some of this enzyme-culture was 

 added to a quantity of pulverized beans, 

 which had been immersed in boiling 

 water, colouring took place in one hour. 



When the temperature of the mass 

 was for five minutes raised to 100°C (a 

 temperature at which enzymic activities 



generally cease) it retained its original 

 colour. 



The chemical process occasioned by 

 the enzymic is explained thus : — 



The beans contain a glucoside Cacao- 

 nine Ceo Hsg Oio Ni, (Hilger) and a large 

 percentage of water. During fermen- 

 tation oxygen is taken up. The result 

 of the fermentation is Theobromine, 

 C7 H8 O2 N4. dextrose G3 II 12 06 and 

 cacao red C17 H22 Oio, 



Ceo H 86 O15 N 4 + 8 H 2 O + 25 O = C 7 Hs 

 0> N 4 + 6C 6 H12O6 + C17H22 O12. 



One molecule of Cacaonine, 8 molecules 

 of water and 24 molecules of oxygen are 

 thus converted into one molecule of 

 Theobromine, six molecules of dextrose 

 and one molecule of cacao red. 



Theobromine is an alkaloid which im- 

 parts to Cacao its pungent and bitter 

 taste. Cacao red has been considered 

 the ingredient from which Cacao derives 

 its characteristic smell and flavour. Dr. 

 Sack by confirming Hilger's and Lazarus' 

 work proves the fallacy of this sup- 

 position ; Cacao red being a perfectly 

 tasteless and colourless powder. 



As unfermented Cacao be5ms give no 

 scent in cooking, it is evident that the 

 scent is acquired through some product 

 of the fermentation. Some pulverized 

 fermented Cacac was distilled and re- 

 distilled with steam, and a volatile oil 

 called cacao-oil produced. This oil 

 possesses the scent and the flavour 

 pecular to cacao. It is present in small 

 quantities, 20 kg. of Cacao yielding only 

 1 c.c of the oil, 



In closing Dr. Sack sums up the con- 

 tents of his paper : — 



" While curing Cacao fungi enter the 

 pulp, setting up an alcoholic fermenta- 

 tion through which the sugar of the 

 pulp is split up into alcohol and oxygen ; 

 the alcohol is by admixture of the 

 oxygen of the air further oxydized 

 forming vinegar, during which process a 

 considerable amount of heat is developed. 

 This constitutes the external fermenta- 

 tion. When the temperature reaches 

 about 45° C. the germinating powers of 

 the seeds are destroyed. As soon as this 

 takes place the internal fermentation 

 sets in, which is an enzymic fermenta- 

 tion process causing the Cacaonine to 

 be split up into Theobromine, Acetrose, 

 Cacao red and Cacao-oil." 



The aim of Cacao-curing is threefold : 

 To remove the useless pulp, thereby 

 insuring the " keeping" of the Cacao; 

 to produce theobromine, which gives to 

 Cacao its stimulating properties ; and to 

 generate Cacao-oil which makes the 

 Cacao palatable. — Bulletin, Botanical 

 Department, Trinidad, No. 58, April, 1908. 



