Nov. 1906.) 



387 



Edible Products. 



Report on Citrate op Lime prom Seychelles, 

 by Professor Wyndham R. Dunstan. 



A sample of citrate of lime manufactured in the Island of Silhouette 

 was forwarded to the Imperial Institute by the Curator of the Botanic Station, 

 Seychelles, and is referred to in a letter from the Governor, No. 29/1906, dated the 

 6th January, 1906, in which a report on the value of the product was requested. 



Description of Sample. — The sample consisted of one pound of a pale «rey 

 powder which had a slight pleasant odour. When moistened, the citrate of lime 

 showed a faint greyish orange-brown colour, and it gave a yellow solution when 

 dissolved in water. 



Examination of Sample.— The substance was examined in the Scientific and 

 Technical Department of the Imperial Institute and was found to contain 84'56 per 

 cent of citrate of lime (calcium citrate) and 0'42 per cent of free acid calculated as 

 citric acid, these constituents being together equivalent to 66'89 per cent of crystal- 

 ised citric acid. It contained a, small quantity of iron salt, equivalent to 7 per cent 

 of ferric oxide, and also a little nitrogenous and mucilaginous organic matter. The 

 proportion of moisture, including water of crystallisation, was 12 57 per cent. 



The analytical results show that this sample of citrate of lime is of good 

 quality, and that it contains very little organic impurity in the form of mucilaginous 

 or colouring matter. No excess of calcium carbonate is present, but the amount of 

 ferric oxide is rather high, owing probably to the use of impure chalk in the 

 preparation of the product. Care should be taken to use a white chalk free from 

 rusty patches for the neutralisation of juice 



The amount of moisture is also rather high, viz., 12 57 percent. Air driedcitrate 

 of lime ought to contain only about 7 to 8 per cent of moisture, and it is desirable that 

 this percentage should not be greatly exceeded in commercial consignments. 



Commercial Valuation. — A portion of the sample was submitted to a large firm 

 of manufacturing chemists in London who use considerable quantities of citrate of 

 lime. This firm reported that the quality of the product is extremely good, especially 

 as regards colour, percentage of citric acid, and freedom from lime and mucilage. In 

 these respects it is superior to many commercial samples. The chief defect is that 

 more iron is present than usual, but, as already pointed out, this can be easily 

 remedied in future by carefully selecting the chalk used for neutralising the juice. 



The present value of citrate of lime is £70 per ton. This is a higher figure 

 than has prevailed for a long time, and the normal value is £i5 per ton delivered in 

 London. 



Conclusions and Recommendations.— It is clear from these results that 

 this sample of citrate of lime from Seychelles is of good quality and compares very 

 favourably with the material at present on the market. It would be desirable to 

 prepare a commercial consignment of the product, taking precautions to avoid the 

 presence of iron, and to forward this for sale in London so that it could be brought 

 to the notice of manufacturers and its value definitely determined. It is of the 

 highest importance that the citrate should be thoroughly dry before being shipped 

 in bulk, as the effect of any dampness is to permit fermentation, which in some cases 

 will go on to such an extent that a substance shipped as citrate of lime arrives at its 

 destination in the form of impure carbonate. Want of care in connection with this 

 point acted as a serious check to the Sicilian industry for many years. 



WYNDHAM R. DUNSTAN. 



26th May, 1906. 



[A fair amount of trade is springing up in citrate of lime, prepared by 

 adding lime juice to chalk, and Ceylon should take a share in i , the lime being 

 abundant here.— Ed.] 



