Carbohydrate Polymers 68 (2007) 226–234 www.elsevier.com/locate/carbpol 0144-8617/$ - see front matter  2007 Published by Elsevier Ltd. doi:10.1016/j.carbpol.2006.12.017 InXuence of unmodiWed and modiWed cycloheptaamylose (-cyclodextrin) on transition parameters of amylose–lipid complex and functional properties of starch Anil Gunaratne, Harold Corke ¤ Cereal Science Laboratory, Department of Botany, University of Hong Kong, Pokfulam Road, Hong Kong Received 26 September 2006; received in revised form 14 December 2006; accepted 15 December 2006 Available online 23 December 2006 Abstract Functional characteristics of starches from cereal, tuber, and root were studied in the presence of -cyclodextrin and hydroxypropyl -cyclodextrin. Both cyclodextrin compounds signiWcantly increased swelling factor, amylose leaching, and solubility of cereal starches while tuber and root starches were less aVected. Gelatinization enthalpy in cereal starches was slightly decreased in the presence of -CD and HP-CD but in tuber and root starches was not aVected. Both -CD and HP-CD decreased dissociation energy of native (wheat, maize, and rice) and synthesized (amylose–lysophosphatidylcholine and amylose–stearic acid) amylose–lipid complex. Reformation of native amylose–lipid complex in cereal starches was decreased by both -CD and HP-CD. Only in cereal starches the presence of -CD and HP-CD during starch pasting result in early swelling and decreased pasting temperature. Both cyclodextrins did not inhibit -amy- lase. The results were consistent with the disruption of amylose–lipid complex within the starch granules by both cyclodextrins by com- plexing with starch lipids, aVecting a range of functional properties of starch.  2007 Published by Elsevier Ltd. Keywords: -Cyclodextrin; Hydroxypropyl -cyclodextrin; Amylose–lipid complex 1. Introduction Cycloheptaamylose (-CD) is a cyclic oligosaccharide composed of seven glucose units arranged in a donut- shaped ring. Its hydrophobic core can complex with a vari- ety of guest organic and inorganic molecules. -CD is widely applied in food, pharmaceutical, and cosmetic industries. In food industry -CD has been applied to remove cholesterol from lard (Yen & Tsui, 1995), egg yolk (Smith, Awad, Bennink, & Gill, 1995) and cream (Ahn & Kwak, 1999), and also used a Xavor carrier for some prod- ucts (Kant, Linforth, Hort, & Taylor, 2004). Hydroxypro- pyl -cyclodextrin (HP-CD) is prepared by substituting hydroxypropyl groups to the hydroxyl groups of the seven glucose molecules that are oriented to form a hydrophobic core in the center of the molecule. Substitution thus may have an eVect on complex-forming ability because of greater hydrophilicity and larger molecular size. In a study of wheat starch gelatinization in the presence of -cyclo- dextrin, it has been shown that -cyclodextrin increases amylose leaching, swelling power, and solubility of wheat starch in a manner consistent with the disruption of amy- lose–lipid complex within the starch granules (Kim & Hill, 1984b) These authors further reported that the eVect is more pronounced at the second stage of gelatinization. In food systems, behavior of the amylose–lipid complex is of technological interest because it can aVect the quality of starch-based food products. For example, retardation of starch retrogradation and bread Wrming (Biliaderis & Tonogai, 1991), prevention of stickiness of dried potato (Hoover & Hadziyev, 1981), and improvement of structural integrity of cereal kernels during cooking (e.g., * Corresponding author. Tel.: +852 2859 0314; fax: +852 3015 6473. E-mail addresses: hcorke@yahoo.com, Harold@hku.hk (H. Corke).