March, 1909. j 



255 



Edible Products. 



composition of the whole grain is as 

 follows :— 



per cent. 



Moisture ... 1075 



Proteins - 10-00 



Oil ... 4'25 



Starch, etc. ... 7P75 



Fibre ... 175 



Ash ... 1-50 



100-00 



In various samples the percentage of 

 proteins may vary from 4 below to 3 

 above the figure given above; that of 

 the oil from \\ below to 4i above, and 

 that of the starch, etc., from 9 below 

 to 5h above. 



The grain of maize does not differ 

 much in its percentage composition from 

 that of wheat, but the proteius {i.e., 

 the nitrogenous substances or "flesh- 

 formers ") are largely " zeins," which do 

 not yield the same elastic dough that 

 the proteins of wheat and rye give, and 

 consequently maize meal does not give 

 such a satisfactory bread. To obviate 

 this a proportion of wheat or rye flour 

 is sometimes mixed with the maize 

 meal for bread-making. Although 

 maize yields inferior bread, many other 

 satisfactory forms of food can be pre- 

 pared from it by skillful cooking. 



The whole grain is made up of 5'6 per 

 cent, skin, 10"2 per cent, germ, and 84'2 

 per cent, endosperm, and these differ 

 considerably in their composition. 



Percentage Composition of Water-free 

 Subalance. 





Whole 



Skin. 



Germ, 



Endos- 





grain. 





perm. 



Proteins 



127 



6-6 



21-7 



12-2 



Oil 



4-3 



1-0 



29-6 



1-5 



Starch, etc. 



79-3 



74-1 



44-7 



85-0 



Fibre 



2-0 



16-4 



29 



0-6 



Ash 



1-7 



1-3 



11 



0-7 





100 



100-0 



100-0 



ioo-o 



The proteins and oil are thus concen- 

 trated in the germ, the fibre in the skin, 

 and the starch in the endosp^i ui. 



In the process of milling the grain is 

 usually first kiln-dried, which facilitates 

 the separation of the skin and lessens 

 the vitality of moulds ; the skin and 

 germ are then separated, and the endos- 

 perm is ground into products of varying 

 degrees of fineness. The offal amounts 

 to from 30 to 35 per cent, of the weight 

 of the whole grain. The separated 

 germs are submitted to hydraulic 

 pressure to obtain the oil they contain ; 

 very large quantities of this are pro- 

 duced in the United States, and it is 



used as an edible oil and for making 

 margarine and soft soap. Other pro- 

 ducts manufactured from maize are 

 starch, glucose, and an alcoholic drink 

 known as "Bourbon whislsy," 



Varieties. — The varieties of the maize 

 plant are very numerous, several 

 hundreds having been recorded, and the 

 differences between them are also great ; 

 thus as regards height they vary from 

 18 inches to 20 feet or more ; in length 

 of cob from 1 to 16 inches ; in the number 

 of rows on the cob from 8 to 24 ; and in 

 individual cobs from 4 to 48 ; the grains 

 may weiyh from 40 to 1530 grains weight 

 per 100 ; the time taken to ripen may be 

 from 1 to 7 months ; and cobs of other 

 colours besides white and yellow are 

 kuown. 



The different varieties have been 

 divided into seven classes according to 

 the nature of their grains, namely :— 



1. The pod corns : these are curious 

 varieties in which each grain is enclosed 

 in a pod or husk ; these are perhaps the 

 original form of the plant. 



2. The pop corns : in these the cob 

 and grains are small, and the endosperm 

 is mostly horny and translucent, there 

 being little or no opaque starchy 

 portion ; when heated over a? fire they 

 burst, with the formation of a white 

 starchy mass, which is eaten as a sweet- 

 meat. 



3. The flint corns : in these the starchy 

 portion of the endosperm is enclosed in 

 the horny portion. 



4. The dent corns : in these the 

 starchy portion of the endosperm is not 

 enclosed by the horny portion, but 

 reaches to the summit of the grain, and 

 the horny portion is at the sides ; as 

 the starchy portion shrinks in drying, 

 the summit of the grain is drawn in and 

 an indentation is produced. 



5. The soft corns : in these the endos- 

 perm is all starchy, and there is no 

 horny portion. 



6. The sweet corns : these are charac- 

 terised by the translucent horny appear- 

 ance of the grains, and by the latter 

 having a more or less wrinkled or 

 shrivelled condition. 



7. The starchy sweet corns : in these 

 the grain externally resembles sweet 

 corn, but the lower half is starchy. — 

 Bulletin of the Imperial Institute, Vol. 

 VI., No. 3, 1908. 



(To be continued.) 



