Foods may contain high concentrations of individual sugars, e.g. jam and boiled sweets with a high sucrose content and where these high concentrations are found there is the risk of crystallization of that sugar. Traditionally in jam and boiled sweet manufacture a combination of heat and acid was used to control the inversion of the sucrose to give a finished blend of sucrose, dextrose and fructose. Whilst potentially all may crystallize if present alone, providing no single sugar is present in high concentration, crystallization in the system is avoided. Generally the greater the number of different components in a sugar mix the more difficult it is for one particular sugar to crystallize. Today, glucose syrups are used to ‘dilute’ the sugar and to provide the added sugars to prevent crystallization. They are ideally suited for this purpose being complex mixtures and such syrups are referred to as ‘doctor syrups’. Additionally, low DE syrups containing high molecular weight glucose oligomers are able to form a matrix with low molecular weight sugars such as dextrose, fructose and sucrose and again prevent localized concentration buildup with attendant risk of crystallization (Howling, 1992). Although glucose syrups are complex mixtures of dextrose and its polymers, only dextrose, maltose and maltotriose are crystalline with the higher saccharides being amorphous in nature.
