FOOD-GRAINS or INDIA. 



number of other nitrogen-compounds in organic food products which 

 are non-albuminoid. Amongst these may be named the ossein 

 and cartilagin of bone and cartilage, and the amides of beet- 

 root, potato tubers, and unripe pulse. But it so happens, that 

 the ripe grains and seeds which are discussed in the present 

 Handbook generally contain but small quantities of nitrogen in 

 forms other than those of the albuminoids, so that we shall 

 not be led into serious error by ignoring their existence. In 

 some of these food-grains, however, small quantities of the 

 compounds called peptones have been found, but these are known 

 to fulfil the same nutritive functions as albuminoids, and indeed 

 are the forms in which the latter after digestion are taken up 

 into the circulatory system of the human body ; they are diffusible 

 through membranes which the original albuminoids are not. 

 Further explanations as to the nitrogen-compounds will be found 

 on pp. 32 and 118. 



Starch, Sugar, and Carbohydrates in general. The carbo- 

 hydrates are so called because they may be regarded as containing 

 hydrogen and oxygen in the proportion in which they form water, 

 associated with carbon. The most important member of the 

 group is starch. This is the chief constituent of all dry food- 

 grains, except those which contain very much oil. Starch occurs 

 mainly in the form of granules, which differ much in different 

 grains both in size and shape, and, it may be added, in their 

 rate of digestion. Uncooked maize-starch and oat-starch are 

 very quickly turned into sugar by the digestive ferment of the 

 saliva or by the diastase of the pancreas; wheat- starch requires 

 a much longer time, and potato-starch is still . more obstinate ; 

 when thoroughly cooked all starches require nearly the same 

 time for salivary and pancreatic digestion. The products of 

 this change are dextrin, maltose, and a little grape-sygar. 

 Dextrin may also be formed by gently roasting starch and in 

 many other ways ; it is more easily digested than starch, but 

 has the same percentage composition, and probably the same 

 nutritive power. It occurs abundantly in parched grain and in 

 the crust of bread. Several varieties of dextrin exist. 



