Edible Products. 



442 



[May 1908. 



The best forms of drier appear to be 

 those in which warm air is drawn over 

 the citrate deposited on shelves ; these 

 driers are of the tvpe of cacao driers 

 described in the West Indian Bulletin, 

 Vol. II, p. 173.* 



As regards the relative advantages of 

 making citrate or concentrated jnice, I 

 have nothing to add to what I said in 

 the West Indian Bulletin, Vol. Ill, p, 

 152. The question appears to me to be 

 still an undecided one. 



In order that those interested in the 

 subject may form some idea of the appli- 

 ances required for the manufacture of 

 citrate, Iappend here plans for a citrate 

 factory c apable of dealing with a crop 

 of about 100 casks of concentrated juice. 



Considerable improvements may be 

 effected in the manufacture of con- 

 centrated juice. In the first place, the 

 juice should be freed from pulp and 

 suspended impurities before coucentrut- 

 ing. This is now found to be a com- 

 paratively simple matter. It is usual 

 to heat the juice in a still in order 

 to recover the essential oil, When 

 the distillation is finished and the hot 

 juice discharged from the still, it is 

 readily clarified either by allowing it to 

 stand in vats to permit the suspended 

 impurities to subside, or preferable, it 

 may be passed through bag filters in the 

 manner mentioned above. 



Concentrated juice prepared from clari- 

 fied lime juice is comparatively free from 

 suspended impurities, and is a superior 

 article to much of the concentrated 

 juice now commonly placed on the 

 market. Some suspended impurities are 

 present, however ; these result from the 

 action of heat on the juice in the process 

 of concentrating, 



It is important that the concentration 

 should be controlled by means of the 

 citrometer in the manner described in 

 the West Indian Bulletin, Vol- II, p. 309, 

 which briefly is this : ' Carry on the 

 concentration untii the citrometer, when 

 immersed in the juice at the boiling 

 temperature shows a density of 60.° t 



A much finer product would be obtain- 

 ed if the juice were concentrated in 

 steam-heated pans instead of over open 

 fires. It is suggested that shallow 

 wooden vats heated by steam coils of 



* Dries of this kind are made by the Blackman 

 Export Co., Ltd., 70, Finsbury Pavement, London. 

 E.C. 



t Citrometers may be obtained from Messrs. 

 Baird and Tatlock, 14, Cross Steeet, Hatton 

 gardeni, London, W. C. ; Messrs. J. L. Long & Co., 

 East cheap, London, E. C, or from most dealers 

 in chemical apparatus. 



copper or block tin will serve for this 

 purpose, I have not seen such appliances 

 in use, but the suggestion is one well 

 worthy of consideration and should 

 commend itself to planters for trial. 



I am informed that there is a demand 

 for the better qualities of concentrated 

 lira 1 } juice for direct use in various arts 

 : nd manufactures in the place of cryst- 

 flli jed citric acid. This is of importacce, 

 for, if a fine quality of concentrated 

 juice, of good colour and free from sus- 

 peaded impurities can be placed on the 

 market, it is reasonable to suppose it 

 will be in demand for those purposes in 

 which a solution of citric acid can be 

 employed in place of the crystallised 

 acid, and should command a higher price 

 than ordinary concentrated juice. 



THE USE OF CENTRIFUGALS 

 FOR DRYING CITRATE. 



Until recently I was of opinion that it 

 was sufficient to press the wet citrate 

 in bags in order to remove the super- 

 fluous water before putting the citrate 

 in the drier. I have, however, recently 

 had an opportunity of conducting some 

 experiments with citrate, as produced 

 on a commercial scale, and have as- 

 certained that a centrifugal will remove 

 a considerable quantity of water from 

 citrate which has already been well 

 pressed. 



The experiments were conducted with 

 a model centrifugal having a basket 

 5 inches in diameter and run at a speed 

 of about 3,000 to 3,500 revolutions a 

 minute ; thus developing a centrifugal 

 force of about the same intensity as that 

 obtained in large centrifugals in com- 

 mercial use. 



The experiments also demonstrated 

 very clearly that citrate can be handled 

 very conveniently by means of centri- 

 fugals. The centrifugal employed for 

 the experiments was lined with twill 

 cloth of the kind used for press cloth. 

 There was no tendency for the citrate 

 to force its way through the cloth, and 

 the water was removed with striking 

 rapidity. The centrifugal removed a 

 considerable quantity of water from 

 citrate which hail already been well 

 pressed. 



The citrate may be washed very con- 

 veniently in the shortest space of time 

 and with the minimum amount of hot 

 water while it is still in the centrifugal, 

 thus producing a pure citrate of good 

 colour. 



