a heavy, watery-white syrup made from maize starch, is also known as ‘liquid glucose’ or ‘glucose syrup’. (This is not quite correct, since it does not consist entirely of glucose, otherwise known as dextrose, but includes a substantial amount of dextrin. However, it gives the right impression.)
Corn syrup is used in the food industry as a sweetening agent in place of sugar, especially for the manufacturing of soft confectionery, ice cream, and similar foods. It is useful because glucose, although less sweet than ordinary sugar (sucrose), crystallizes much less readily. Also, corn syrup has no flavour of its own, and in some parts of the world it is less expensive than ordinary sugar.
In human digestion, glucose is formed by the hydrolysis (breaking down) of starch and other carbohydrates. Until recently, all corn syrup made industrially was produced by a method which mirrored on a large scale what happens inside humans: the heating of maize starch with an acid broke down the large molecules of starch into their component parts, mostly molecules of dextrose (glucose).
Recently, a new method has been adopted: hydrolysis carried out by enzymes, which can work at a moderate temperature. Nor is this all. Certain bacteria (Streptomyces spp), with which the syrup can be inoculated, will produce other enzymes which convert some of the dextrose to fructose, which is considerably sweeter than either glucose or ordinary sugar (sucrose). If this procedure is followed, the result is a ‘light fructose’ syrup which is much sweeter than ordinary corn syrup, although its energy value is no greater than that of any other common sugar.
Ordinary corn syrup can be refined further into what is called ‘corn sugar’ or ‘solid glucose’. This has a lower content of dextrin, but it is still not pure glucose.
Alan Davidson was a distinguished author and publisher, and one of the world's best-known writers on fish and fish cookery. In 1975 he retired early from the diplomatic service—after serving in, among other places, Washington, Egypt, Tunisia, and Laos, where he was British Ambassador—to pursue a fruitful second career as a food historian and food writer extraordinaire. Among his popular books are Seafood of South-East Asia, North Atlantic Seafood, and Mediterranean Seafood. In 2003, shortly before his death, he was awarded the Erasmus Prize for his contribution to European culture.
