Although carbohydrates are usually denned as compounds of carbon, hydrogen, and oxygen, the last two elements being in the proportion in which they occur in water, other substances, such as acetic acid, lactic acid, and inosite exist, which answer to this description and yet are not carbohydrates. Chemically speaking, carbohydrates are really aldehydes or ketones (aldoses or ketoses) of polyhydric alcohols, and are probably built up by combination of a number of molecules of formaldehyde - C2HO. Those derived from hexatomic alcohols are divided into three groups: -

I. Monosaccharoses (Or Monosaccharides), C6HI2O6

(a) Dextrose, glucose, or grape sugar, found in fruits, honey, and to the extent of 0.12 per cent. in the blood, as well as other parts of the body.

(b) Laevulose, often called fructose.

(c) Galactose.

II. Disaccharoses (Or Disaccharides), CI2H22O14

(a) Saccharose, or cane sugar.

(b) Lactose, or milk sugar.

(c) Maltose, or malt sugar.

III. Poly Saccharoses (Or Polysaccharides), C6HI0O5N

(a) Starch.

(b) Dextrin and its varieties, erythro-dextrin and achroodextrin.

(c) Glycogen, or animal starch, found in liver, muscle, white blood corpuscles and other tissues.

(d) Cellulose.

Comparing these groups side by side after equalisation of their carbon atoms, their relationship is seen at a glance: -

Monosaccharoses ... ... ... CI2H24OI2

Disaccharoses ... ... ... CI2H22OI1

Polysaccharoses ... ... ... CI2H2OO10

H2O subtracted from two or more molecules of mono-saccharose results in the formation of disaccharose, and the loss of another molecule of water produces a polysaccharose.

Effect Of Cooking

The nutritive ingredients of all vegetables are contained in cells whose bounding wall is cellulose, and even starch grains themselves are composed of concentric envelopes of starch proper, amylum or granulose, alternating with layers of starch cellulose or farinose. The digestive enzymes have little or no effect upon cellulose, but fortunately the process of cooking causes such a swelling of the contained starch granules that the cellulose envelope is ruptured and the digestive juices are permitted to come into contact with the granulose. (See Chapter XII (Raw Food In Theory And Practice). for further details.)