Molecular encapsulation of flavours as helical inclusion complexes of amylose

The formation of helical inclusion compounds of amylose with different typical flavour compounds was optimised. Maximal guest molecule contents between 5.7 and 10.4 wt% in the complex were obtained. This corresponds to segments of 8-16 anhydroglucose units in the amylose helix per included guest molecule. Contents of this order of magnitude approach the maximum content of guest molecules possible in the core of the amylose helix. A method for determining the association constants for complexing using headspace gas chromatography was applied. Constants ranging from K=29-1080 l/mol were obtained. The association constant with the same guest molecule is strongly dependent on the origin and the chain length of the amylose. Flavours with low boiling points such as hexanal (b.p. 128 ° C) form complexes which are completely stable under freeze-drying conditions and show long-term stability. Flavour release was only observed at high temperatures (80 ° C). On addition of water, guest molecules are quickly released but with water activities of a(w)=0.3 - as found in normal dry food - the complexes are stable at room temperature. Complexes with two or more guest molecules show a remarkable influence on complexing ability induced by the co-inclusion compounds. The overall content of guest molecules is lower compared to that obtained with individual flavour compounds. © 2004 Elsevier Ltd. All rights reserved.