Evidence of starch inclusion complexation with lactones

Starch, in particular the linear amylose, is able to form inclusion complexes with a wide spectrum of ligand molecules, among them flavor compounds. The complexing ability of a homologous series of gamma- and delta -lactones with potato starch was followed by amperometric iodine titration, differential scanning calorimetry, and wide-angle X-ray diffraction measurements. Lactones with a Linear chain of a size greater than or equal to C-5 form inclusion complexes with starch, whereas lactones with a short linear chain, such as gamma -heptalactone, show poor complexing ability. The thermal stability of starch-lactone complexes increases with increasing chain length of the lactone. In general, lactones induce tl;e formation of V-h helices. Only delta -decalactone complexes with starch were not definitely identified as V-h amylose helices. Complexation of starch dispersions with lactones induce turbidity and gelation or phase separation, both phenomena being the result of microphase separation.