Sugar cane existed in New Guinea 12,000 years ago and was cultivated in Egypt and the coastal lands of the Mediterranean about 3000 BC. A soft, sweet and thin-stemmed variety, known as Criolla, was introduced into the West Indies in 1493 by the explorer Christopher Columbus. During the eighteenth century, sugar cane plantations developed rapidly in the colonies of many European countries as a result of the cheap supply of slave labor drawn from the African continent. The modern varieties of sugar cane are hybrids of Saccharum officinarum, S. robustum and S. spontaneum, which have been bred to resist Mosaic disease and to give high yields.
The sugar beet plant was discovered comparatively recently. As a weed, Beta maritima, it was found on Mediterranean seashores. The variety cultivated about one hundred years ago contained only about 5 per cent by weight of sucrose, but later varieties, such as Beta uulgaris, contain up to 20 percent sucrose. Sugar beet is grown in temperate regions and accounts for around 40 per cent of world sugar production. The rest is obtained from sugar cane grown in tropical regions
Granulated sugar is over 99 per cent pure sucrose, which is a disaccharide with the chemical formula C12H22011. It can be transformed to two other sugars, glucose and fructose, by the addition of one molecule of water. This process of hydrolysis is called inversion and can be accomplished by heating a sucrose solution with a dilute acid or by the action of enzymes. The resulting glucose and fructose are referred to as invert sugars and, unlike sucrose, they are able to reduce copper in a Fehlings solution (an alkaline solution containing Rochelle salt and cupric sulfate) to a precipitate of cuprous oxide.
The sugar beet at maturity contains virtually only sucrose but the sugar cane may contain appreciable quantities of invert sugars which, fortunately, are at a minimum at maturity.