Physical and Chemical Papers. 81 



A STUDY OF THE GELATINIZING AGENTS, PASTY MA- 

 TERIALS AND THICKENERS USED IN 

 FOOD PRODUCTS. 



P.y Lioiix A. ('i).\i;i)OX. 



THE use of gelatinizing agents, pasty materials and thicken- 

 ers in food products has become quite prevalent in recent 

 years. Hence a study of these materials and their detection in 

 food products is important to the chemist. Quite often thick- 

 eners, pasty materials and gelatinizing agents are used to 

 cheapen the genuine articles, in that they are used to repre- 

 sent the genuine articles. In this class might be mentioned 

 agar-agar, which has been found in imitation lemon slices ; 

 starch, agar-agar and gelatine in imitation jelly; dextrin in 

 imitation cocoa cubes ; then again these materials are used to 

 cover up inferiority. In this class might be mentioned albu- 

 men, or white of egg, which is sometimes used to glaze coffee 

 beans to make them appear better than they really are. Again, 

 the thickenings, etc., are used in such products as ice cream 

 and custards, primarily to add bulk to the product, and to 

 give the material in which they are used a frothy appearance. 

 They are also used in this connection to make the ice cream and 

 custards "stand up." A great many ice-cream manufacturers 

 use a so-called "ice-cream powder." These "ice-cream powders" 

 vary in composition, but generally contain one or combinations 

 of the following: dextrin, acacia, tragacanth, gelatine, albu- 

 men, and starch. 



This paper will deal more specifically with the .detection of 

 these gelatinizing agents, pasty materials, and thickeners. I 

 will describe briefly the more common ones now in use. 



Gelatine is usually regarded as an albuminoid, but does not 

 come strictly within the requirements of the definition of 

 simple proteins, which possess essentially the same chemical 

 structure as the other proteins, but are characterized by great 

 insolubility in all neutral solvents. Gelatine is prepared from 

 bones and other animal parts, and is insoluble in cold water, 

 but soluble in hot water. When the hot-water solution con- 

 taining one per cent or more of gelatine cools it forms a jelly. 

 — G 



