284 The Fermentation of Cacao 
alcohol; (4) the saponification number ; (c) 
the iodine value; (d) the volatile insoluble 
acids. The author also determines the acidity 
of the sample. In German tests the refracto- 
meter index, the melting point, and Bjork- 
lund’s test are also required. Robin detects 
coco-nut oil (5 per cent.) by finding the solu- 
bility in alcoho! (55°5°) and comparing the. 
co-efficient obtained with the saponification 
number. For pure cacao butter the constant 
lies between 7° and 8°, but is considerably de- 
creased in presence of very small amounts of 
coco-nut oil (Axx. de Chim. Anatl., 1906, p. 454, 
1907, pp. 14, 40, 87, 181). Coco-nut fat gives 
a figure of 15 to 18 (cc. N/to NaOH for 
5 grm.) for volatile soluble acids, considerably 
higher than that for cacao butter, and at the 
same time raises the saponification number 
and lowers the refractive index and the iodine 
figure. Byjorklund’s ether solubility test is 
valuable for the detection of wax, margarine, 
and paraffin, especially when the melting-point 
also is taken of the fat which is deposited, on 
cooling the solution too. This melting-point .. 
should not exceed 30°. The acidity of com- 
mercial cacao butter, when not rancid, is not 
greater than o'5 per cent., expressed as oleic 
acid. Cacao butter is also adulterated by the 
addition of fat from the pellicle and other 
waste parts of the plant. This fat is less 
aromatic than the true ‘butter’ and rapidly 
becomes rancid. It is hardly possible to detect 
this adulterant with certainty.” 
