214 



The following points are noted as having been brought out by the limited data 

 obtained : 



(1) Any method in which portions of the extract are poured off into shell vials, etc., 

 for the determination of the iodin number, as is customary in the determination of 

 this constant with oils and fats, should be avoided, for as before stated it is absolutely 

 impossible by this method to obtain two portions of identical composition. 



(2) Iodin numbers determined on the nonvolatile ether extract of paprika, which 

 by the high value of this constant would appear not to be adulterated with olive oil, 

 are found when made on the product obtained by the official method of extraction 

 to be considerably lower than those obtained on the product produced by extraction 

 with cold solvents, indicating perhaps the presence of drying oils; while, as is to be 

 expected, the percentage of nonvolatile ether extract is lower. On the other hand, 

 with commercial paprikas adulterated with olive oil the difference between the iodin 

 numbers obtained by the two methods of extraction is not so marked. Extraction 

 with cold petroleum ether, boiling point 50-60 gives a nonvolatile extract about 

 1 per cent lower than is obtained by the use of an equal volume of sulphuric ether 

 under identical conditions. In the following table samples Nos. 1 to 8 are commer- 

 cial paprikas sent in on suspicion of adulteration with olive oil while No. 9 is a pure 

 product prepared by grinding the shells of Hungarian paprika. 



Comparison of methods for determination of iodin number and nonvolatile ether extract. 



DETERMINATION OF STARCH IN COCOA PRODUCTS. 

 By W. L. DUBOIS. 



The provisional method for the determination of starch in cocoa and cocoa products 

 requires grinding of the sample in a mortar repeatedly with ether and pouring the 

 solution through filter paper each time until the fat is extracted. With sweetened 

 material the fat-free residue is then rubbed in a mortar to a paste with water and 

 filtered on the same paper, the process being repeated until all the sugar is removed, 

 which requires about 500 cc of water. This process is a very slow and tedious one. 

 The manipulation of the sample in the mortar with ether both in the grinding and 

 subsequent pouring requires extreme care to prevent loss. The filtration in many 

 cases is very slow and with sweetened samples it often takes two days to wash with 

 500 cc of water. In order to overcome this objection the following procedure was tried : 

 Four grams of the unsweetened sample or 8 grams of the sweetened goods are shaken 

 with 100 cc of gasoline in an ordinary 8-ounce, short neck, nursing bottle until the 

 material is completely disintegrated; the bottle is whirled in a centrifuge until the 

 supernatant liquid is clear and the gasoline drawn off with a small tube attached to 

 vacuum pump and the process repeated. This procedure removes practically all the 



