210 AGRICULTURAL CHEMISTRY 



is overripe, and then avoiding bleaching and leaching. 

 Rape, turnips, cabbage, parsley and onions contain essen" 

 tial oils. 



285. Synthetic Production of Essential Oils. 



Nearly all of the essential oils found in fruits, as pine- 

 apple flavor, peach flavor, and vanilla, are capable of 

 being produced synthetically in the laboratory. They 

 are definite chemical compounds, and it is only necessary 

 to bring together, under the right conditions, the radicals 

 or component parts for them to unite and form these 

 compounds. Pineapple flavor is ethyl butyrate. The 

 acid constituent of this salt, butyric acid, is found in stale 

 butter, while the basic part of the radical is present in 

 ether and alcohol. The chemical union of butyric 

 acid and the ethyl radical gives ethyl butyrate or pineapple 

 flavor. In fact, nearly all of the commercial fruit flavors 

 are laboratory products. When properly made, they are 

 identical with the same flavors as found in fruits, but 

 frequently they contain traces of acid or alkaline products 

 used in their preparation. 



286. Amount of Essential Oils in Plants. The 



amount of essential oils in plants and foods is small, less 

 than i per cent, and usually only a fraction of a per cent. 

 This small amount is, however, sufficient to give a char- 

 acteristic taste. 



287. Food Value. Some of the essential oils of fod- 

 ders, like the organic acids, exert a favorable influence 

 upon digestion by imparting palatability and stimulating 

 the secretion and flow of the digestive fluids. They are 



