DOI: 10.1094/CC-82-0131 |  VIEW ARTICLE

Water-Barrier Property of Starch Films Investigated by Magnetic Resonance Imaging.

Yi-Lin Chung (1) and Hsi-Mei Lai (1,2). (1) Department of Agricultural Chemistry, National Taiwan University, No. 1, Roosevelt Rd., Sec. 4, Taipei 106, Taiwan. (2) Corresponding author. Phone: +886-2-23630231 ext 3061. Fax: +886-2-23633123. E-mail address: <hmlai@ntu.edu.tw> Cereal Chem. 82(2):131-137. Accepted September 29, 2004. Copyright 2005 American Association of Cereal Chemists, Inc.

Water-barrier property of a starch film was investigated using a magnetic resonance imaging (MRI) technique with a two-gelatin gel model system. A film was placed between two gels, which contained different amounts of sorbitol leading to high water activity (H-gel) and low water activity (L-gel) gels. The assembled model systems were used to investigate the changes of water status of gels during storage. A multislice-multiecho pulse sequence was applied to acquire a series of transverse relaxation decay images, then spin-spin relaxation time (T(2)) of water protons of gelatin gels was calculated. The water migration from H-gel to L-gel and water redistribution within the gel during storage was evaluated based on the results of T(2) maps and T(2) profiles. The water transference rate was significantly influenced by the types of film used to separate the gels. The starch-beeswax composite film had better water barrier ability than the starch fim. The combination of two-gelatin gel model system and MRI techniques allowed the evaluation of the water-barrier property of edible film prepared from biopolymers and also gave an insight into the physical structural change and chemical environmental conditions of gels due to water migration.