January, 1909.] 



11 



Oils and Fats. 



take place as the result of an enzyme 

 in the foot, or be caused by one in 

 the meat, which is dormant until 

 rendered active by some product of 

 metabolium in the foot. It i,°, however, 

 not possible to prove by an increase 

 in free fatty acid the presence of any 

 fat-splitting enzyme in the coconut. 

 Such an enzyme may exist, but under 

 such conditions that any large excess 

 of free acid must be used up by the 

 growing plant before the process can 

 continue. 



To summarize in a word the changes, 

 determinable by chemical analysis, in 

 the growing coconut :— 



Oil is lost by the meat ; it is not 

 taken up as such by any other portion 

 of the nut, but is either oxidised to 

 furnish energy for the growing plant, 

 or is split up and transformed by 

 progressive synthesis into sugar and 

 finally into cellulose. Sugar is lost by 

 meat and milk, but a corresponding 

 quantity is gained by the foot, the 

 total quantity in the nut remaining 

 approximately the same. A small amount 

 of crude fibre is lost by the meat, but 

 a much larger quantity is produced in 

 the sprouts and roots. 



Note 3 deals with the action on copra 

 of micro-organism in pure culture. 



The Philippine Journal in 1906 recorded 

 the fact that moist copra is attacked 

 by micro-organisms with consequent 

 splitting up and destruction of the oil 

 —this action being most pronounced 

 when the copra contains from 10 to 15 

 percent, water. Under these conditions 

 the growth of mould predominated 

 largely over that of the bacteria. With 

 a much larger percentage of water, and 

 when the bacteria were in excess of the 

 moulds, the destruction of fat is greatly 

 diminished. These observations led 

 logically to the conclusion that hydro- 

 lysis of oil in copra was due to mould 

 action alone, although the then available 

 data did not exclude the possibility of 

 symbiosis and interdependence, in this 

 fat-splitting process, between moulds 

 and bacteria. Dr. Edwards of the 

 Biological Laboratory of the Philippine 

 Bureau of Science, in pursuing further 

 research into this question, separated 

 some fifteen different organisms from 

 mouldy copra and coconut meat, and 

 finally succeeded in isolating in pure cul- 

 tures the majority of the growths 

 present. The identification of every 

 organism was found to be impossible, and 

 indeed the majority of them are probably 

 new and undescribed. Hoivever, the 

 main object of the experiment, viz., the 

 differentiation between moulds and 

 bacterial action has been accomplished. 



Taking the total weight of dry copra, 

 every active mould culture brought 

 about a decided loss ranging from 5 to 

 11 per cent., while only one bacterium 

 was found to cause any appreciable loss. 



The moulds destroy a certain percent- 

 age of the oil, and the greater portion of 

 the loss is attributable to this cause. 

 These losses, which represent 8 9 to 19-9 

 per cent, of the original weight of oil, 

 are accompanied by hydrolysis with the 

 formation of fatty acids and glycerine. 



There seems to be no direct relation 

 between the percentage of free fatty 

 acid evolved and the total quantity 

 of oil destroyed at the time, since low 

 as well as high precentages of free 

 acid show the same loss of oil. As 

 already mentioned, only one bacterium 

 caused diminution of oil, and this only 

 to the extent of 8 grammes, which is 

 less than that brought about by the 

 mould with the weakest action, and 

 the loss is not accompanied by hydrolysis 

 in this case. On the other hand, one 

 bacterium appears to have caused a 

 slight gain in total oil. The sugar is 

 almost completely destroyed by all 

 moulds, whereas bacteria may be said 

 to produce no effect here. 



Looking at this matter from a com- 

 mercial standpoint, it may be stated that 

 mouldy copra must have suffered a loss 

 in total oil-content which may reach the 

 neighbourhood of 20 % under the most 

 favourable conditions, but certainly to 

 an extent to be taken into account in the 

 purchase of such copra. Such inferior 

 produce undoubtedly cannot give as good 

 a yield of oil as that which has been 

 carefully dried and preserved. On the 

 other hand, in the case of badly cured 

 copra, if a sufficient quantity of water 

 (about 15 %) is present, it is bacterial 

 action and not mould action that will 

 come into play ; so that no diminution of 

 oil would be observed, though bacteria 

 so disintegrate and change the copra 

 that a slimy soft mass characterised by an 

 objectionable odour, and difficult to work 

 so as to procure pure oil reasonably free 

 from acid, results. 



In the Philippines a large amount of 

 copra is dried by means of fires in pits, 

 the meat being placed on bamboo 

 gratings above and the fuel beneath. It 

 is not impossible that the smoking 

 to which the copra is subjected has a 

 slight antiseptic action which would 

 tend to diminish the subsequent growth 

 of oiganisms, and so to preserve the oil. 

 Nevertheless, the arguments are all in 

 favour of a clean white, prefectly dried 

 copra, which will not afford a medium 

 for the growth of organisms, unless the 



