Inclusion complexes of starches with hydrocarbons

Starch formed inclusion complexes with aliphatic and aromatic hydrocarbons. The amount of included hydrocarbons depended on the starch variety. Waxy m aize starch was superior for this purpose as it included over 7% of hydroca rbons. Tapioca, maize and potato starches included gradually lesser amount of hydrocarbons. Oven-dried starches performed better than air-dried ones. Aromatic hydrocarbons complexed more readily. Polarity is, perhaps, the mos t essential factor governing the complexation. Less polar hydrocarbons were complexed more readily. The FT-IR spectra taken in the Kubelka-Munk mode a nd CLBM studies (the hedgehog effect) revealed that complexing hydrocarbons expelled part of the amorphous content of starch granules to form internal empty domains. In such domains, hydrocarbons were held with involvement of local van der Waals and dispersion forces of D-glucose units rather than b y formation of helical complexes with amylose and amylopectin. (C) 2000 Els evier Science Ltd. All rights reserved.