Lesson 29 :Processing and Preparation of Sugar and Related Products
The presence of substances that interfere with crystallisation of sucrose in fondant and other candies is desirable, but at an optimum level. Glucose, corn syrup or invert sugar either added directly or formed by acid hydrolysis affect crystallisation because they make the sugar solution more soluble and therefore, decrease the ease of crystal formation. Other substances including fats from milk, cream, butter, margarine and chocolate and proteins from milk and egg white do not themselves crystallise. They physically interfere with the process of crystallisation, retarding the growth of crystals. All these interfering substances aid in fine crystal formation and smooth texture in crystalline candies.
The temperature at which crystallisation occurs affect the size of crystals, primarily because it affects the rate of crystallisation. In general, the higher the temperature at which crystallisation occurs, the faster the rate of crystallisation and the more difficult is to keep the crystals separated, resulting in larger crystals. Cooling the mixture to about 40oC before starting at lower temperatures. High viscosity is a further aid in the production of fine crystals because it retards crystallisation. Too low a temperature may also hinder the formation of many nuclei.