THE SUPPLEMENT TO THE 



Tropical Agriculturist and Magazine of the C. A. 8. 



Compiled by A. M. & J. FERGUSON. 



No. 2,] FEBRUARY, 1910. [Vol. VI. 



MOISTURE IN COPRA. 



I. 



Moisture gives rise to deterioration in many 

 commodities produced in India, and we have 

 repeatedly drawn attention to the importance, 

 of improved methods of drying. The deterio- 

 ration results from the fact that various chemical 

 and bacterial changes take place in the presence 

 of moisture. These induce either direct con- 

 sumption or conversion of valuable constituents, 

 or injury through the development of heat, or 

 such defects as an undesirable colour, smell or 

 taste. It may probably be said that the com- 

 monest agents in such accidents are moulds 

 and bacteria, though it was seen from Mr 

 Lefroy's interesting paper (published in our*) 

 issue of the 18th November that the destruction 

 of wheat by weevil is dependent on moisture and 

 may be controlled by its elimination. One of the 

 commodities most sensitive to action by micro- 

 organisms is copra. This is due to the presence 

 in it of constituents on which moulds and bac- 

 teria feed ; but moisture must also be present in 

 a certain measure before these forms of life can 

 germinate. When these conditions exist and 

 organisms appear, the copra deteriorates both 

 through the destruction of the oil proteids and 

 carbo-hydrates and through the establishment 

 of bad colour, taste and smell. The copra 

 industry is one associated in India mainly with 

 the coast line and the banks of great waterways. 

 In these regions the air is commonly moist, 

 so that drying is relatively slow. During the 

 rainy season drying is impracticable in the open 

 and the trade is entirely arrested. At other 

 seasons when storms, showers or heavy dews 

 are experienced, it is retarded and the product 

 is apt to be deficient both in quality and in 

 content of oil, sugars and albumen. 



The Philippine Journal of Science for February 

 15th, 1906, contained a useful paper on the 

 Keeping Qualities and the Causes of Rancidity in 



* Indian Trade' Journal. — A, M. & J. F. 



22 



Coconut Oil. The experiments described inclu- 

 ded a number with copra ; and the author said : — 



" The most important fact brought out by this work is 

 that by far the greatest deterioration which an oil under- 

 goes takes place in the copra itself. After an oil has 

 been expressed from the dried meat, its change on 

 standing is very slight compared with that which is 

 found in the same time while it is in copra. No great 

 amount of rancidity was developed in any case until signs 

 of mould or bacterial growth were visible on the surface of 

 the copra. From this it would seem very probable that 

 the splitting up of fat and the accompanying rancidity 

 produced in copra are in a large measure due to the action 

 of micro-organisms which have an excellent culture medium 

 in the sugar, albuminoids and water which exist together 

 with the oil in coconut meat." 



The author proceeds to quote other autho- 

 rities who have shown that cotton-seed meal 

 containing a sufficient amount of water is at- 

 tacked by moulds and bacteria and that the oil 

 therein is, on long standing, almost completely 

 destroyed. He then details the sets of experi- 

 ments made with copra (a) when inoculated 

 with a solution from an old mouldy sample and 

 (6) when left exposed to attack by such micro- 

 organisms as might be present in the atmos- 

 phere. It was seen that the two sets of speci- 

 mens behaved very much alike. The period of 

 experiment was only fourteen days and the 

 actual loss of oil was, therefore, in no case great 

 but, as the author says, " it was sufficiently 

 marked to show that it also chiefly took pla,ce 

 in those tubes which contained a growth of 

 mould ; the loss of substances other than oil, on 

 the contrary, was considerably less where the 



mould was most vigorous." "The large loss 



in substances other than oil (sugars, albumi- 

 noids, etc.,) was confined to those tubes in which 

 bacteria predominated— that is, those contain- 

 ing more than 16'67 per cent of moisture— indi- 

 cating that bacteria obtain their carbon and 

 hydrogen chiefly from the sugars, albuminoids 

 and cellulose which are present in copra, while 

 moulds directly attack the oil." 



" The most important point to be considered 

 from a practical point of view is," according to 

 the author, " that copra containing as little as 

 9 per cent of moisture is still attacked by moulds 



