170 



The Supplement to the Tropical Agriculturist 



with the consequent production of free acid 

 and colouring matter as well as loss in weight 

 of oil. Unfortunately the copra produced in 

 the Philippine Islands ordinarily contains from 

 9 to 12 per cent of water, a condition which is 

 the most favourable for mould growth and for 

 the deterioration of the oil. The remedy for 

 this is obvious. A more complete drying to re- 

 duce the water content to 5 per cent or less will 

 produce a copra which is unattacked by orga- 

 nisms. Such a product, kept dry, will remain 

 fresh and sweet for a long time. In a previous 

 part of this paper I have shown that copra, once 

 sufficiently dried, may be kept during the dry 

 season in Manila without any change what- 

 soever ; but recent experiments prove this 

 not to be the case during the rainy one, even 

 with anhydrous copra." These experiments, 

 as described by the author, showed that 

 copra entirely free of water could in one 

 month of the rainy season acquire sufficient 

 moisture to develop moulds after the con- 

 taining vessel had been closed, while an- 

 other sample which remained exposed to the 

 atmosphere for two months changed less. 

 As regards India it does not appear that 

 any complete analysis has been made for 

 the purpose of determining the percentage 

 of moisture in purely Indian copra, but 

 it is believed to be about 6 per cent. But 

 to return to the Philippines. We quote also 

 the conclusion on this point arrived at by the 

 same investigator after further experiments 

 which were recorded in the same Journal 

 for 1908 :— 



" The results given above, when applied to the ques- 

 tion of the diminution iD value of commercial copra, 

 would render it certain that such copra, if mouldy, has 

 suffered a loss in total oil, of course not in all probabi- 

 lity as great as I noticed in some cases (19'9 per cent), 

 for my copras were placed under the most favourable 

 conditions for the maximum of mould action ; but, never- 

 theless, this change must amount to a sufficient quan- 

 tity to be considered in the purchase of copra which 

 has suffered from the action of moulds. 



" Such material undoubtedly cannot give as good a 

 yield of oil as others which have been carefully dried 

 and preserved. However, another factor must also be 

 considered. Poorly dried and preserved copras, if a 

 sufficient quantity of water (above 15 per cent) is pre- 

 sent, suffer from bacterial and not from mould action ; 

 in which event no diminution of oil would be observed, 

 but, nevertheless, bacteria so disintegrate and change 

 the copra that a slimy, soft mass, difficult to work so 

 as to procure pure oil reasonably free from acid, results. 

 A bad odour also frequently accompanies such copras." 



It is thus evident that thorough drying is 

 of crucial importance in the production _ of 

 copra. The author of the paper from which 

 we have quoted conducted a series of experi- 

 ments in several methods of drying, and we 

 propose to review his results in our next issue. 

 — Indian Trade Journal, Dec. 23. 



II. 



Since the quick and through drying of copra 

 has been shown in the last issue of the Indian 

 Trade Journal to be of such vital importance in 

 order to insure the production of a pure oil, the 

 results of an investigation made in the Philip- 

 pines of various methods of copra drying may 

 prove of interest. The simplest mode of drying 

 copra is to expose the nuts, cut in halves, to the 

 action of the sun during about five days. This 

 method, although slow, produces a very fair 



quality of copra. However, a sudden rainstorm 

 or a succession of cloudy days is sufficient to 

 start mould and bacterial growth, with the con- 

 sequent deterioration of the copra. Considerable 

 loss, due to the attacks of insects and animals, 

 is also suffered during the long period of drying, 

 and the finished product very seldom contains 

 less than 9 per cent of moisture. 



A much quicker method is the one carried out 

 by laying the half nuts, face downward, on a 

 bamboo grating placed over a slow fire of coco- 

 nut husks. After being dried in this manner 

 over night, the nuts are removed from their shells 

 and are then again placed over the fire, where 

 they are allowed to remain tor from four to five 

 hours longer. This process, although it is cheap 

 and comparatively rapid, has the disadvantage 

 of yielding a dark-coloured product which has a 

 smoke-like taste and odour, and it also tends to 

 form a hard, burnt coating over the surface of 

 the nut while the inside is left in a compara- 

 tively moist state. Commercial copra, prepared 

 in this way, contains from 9 to 13 per cent of 

 moisture. 



The hot-air method of desiccation has 

 been used successfully for a long time in the 

 preparation of coffee, cocoa, dried fruits, etc., 

 and is at present in quite extensive use for 



THE MAKING OF COPRA IN CEYLON, 



where it is said to give a very pure, light- 

 coloured product. The type of apparatus used 

 in that island essentially consists of a large 

 chamber filled with wire trays upon which the 

 coconuts are placed and over which a current of 

 hot air, driven by a fan, is passed. In Trinidad, 

 there is now in operation a rotary hot-air drier 

 which, it is stated, is better than any other 

 a pparatus now in use. 



For the purpose of testing the efficiency of 

 the stationary form of hot-air drier, a double- 

 walled, rectangular galvanized-iron box, having 

 an internal capacity of about - 2 cubic metre 

 was constructed. Three galvanized-iron trays, 

 perforated at one end, were set in this box in 

 such a manner that the stream of hot air, enter- 

 ing through a 20-centimetre pipe at the bottom, 

 was compelled to pass over each in turn before 

 escaping at the top of the apparatus. A con- 

 stant current of air was obtained by means of 

 a small electric fan which was connected with a 

 section of 15-centimetre pipe, so arranged that 

 it could be heated by a small kerosene stove to 

 any desired temperature. The apparatus had 

 a maximum capacity of 24 nuts split in halves, or 

 12 nuts when shredded. In the first experiment 

 four nuts were split in halves and placed on the 

 bottom tray. The temperature of entering air 

 was 56°C. and of escaping air 51°C. The time 

 of drying was 20 hours. The copra dried at this 

 comparatively low temperature was very white 

 and of the best quality. A sample of oil ex- 

 pressed from it contained 0'08 per cent free acid. 



In the second experiment the meat from 

 twelve nuts was shredded by hand and treated 

 for one day in the same manner as in the pre- 

 ceding experiment; it was then allowed to stand 

 at room temperature over night and completely 

 dried on the following day. The substance in 

 the bottom tray naturally desiccated much more 



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