Effects of dextrinization and octenylsuccinylation of high amylose starch on complex formation with omega-3 fatty acids (EPA/DHA)

Abstract

High amylose maize starch (70% amylose) was dextrinized in an acid/alcohol solution (0.36% HCl in ethanol, 50 degrees C for 24 h), and the starch and its dextrin were octenylsuccinylated (DS 0.019) to be utilized as complex forming agents for omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid). A fish oil was used as the fatty acid sample and dispersion with starch and fish oil was stirred at 60 degrees C for 3 h and cooled at an ambient temperature for 3 h. The complex was isolated as the precipitates after centrifugation (25,000 x g, 25 degrees C for 30 min), and then the recovery of fatty acids in the complex and crystalline characteristics of the complex were examined. Dextrinization improved the efficiency of complex formation, increasing the recovery of fatty acids and decreasing the recovery of solid precipitates. Octenylsuccinylation, however, retarded the complex formation showing a decrease in fatty acid recovery. It was hypothesized that intermolecular complex between amylose and octenyl group in the substituents was formed during the reaction because the modified starch and dextrin without fatty acids showed a new endotherm (at around 100 degrees C) in their thermograms. Because of the possible competition between the substituents and fatty acids in complex formation, octenylsuccinylation hindered the complex formation between amylose and fatty acids. The fatty acid complex particles prepared with native starch or dextrin showed average particle size less than 400 nm with zeta potential below -40 mA, assuring the dispersion stability during an ambient storage. (C) 2017 Elsevier Ltd. All rights reserved.