Crystals

Abstract

A few foods—salt, table sugar, and especially rock candy—are obviously crystals. They look like the crystals familiar from science classes and science fiction films; angular solids with shiny faces and clear geometric shapes. However, there are many other smaller and less immediately obvious crystals in foods. The hardness of butter and ice cream depends on the proportion of the oil or water respectively that is crystalline, even though the individual fat and ice crystals are too small to be seen by the naked eye. Likewise in a starch granule, parts of the amylopectin molecules are present in tiny crystallites that melt on gelatinization. All these crystals contribute to the properties of food and share some common features that make them worth considering as a class in their own right.