Preparation and characterization of annealed-enzymatically hydrolyzed tapioca starch and the utilization in tableting

Abstract

Tapioca starch was annealed at 60°C for 90 min followed by hydrolysis with α-amylase at 60°C at various lengths of time (30, 60 and 120 min) to obtain high-crystalline starches. The reaction products were subjected to spray drying to obtain annealed-enzymatically hydrolyzed-spray dried tapioca starch (SANET) in the form of spherical agglomerated granules. The properties of SANET were compared with those of annealed-spray dried tapioca starch without enzymatic treatment (SAMT) and native-spray dried tapioca starch (SNT). Scanning electron micrographs of the starch samples were used to study the morphological changes and to suggest the mode of enzyme attack during hydrolysis. The á-amylase preferentially attacked the interior of the starch granules, leaving a deep round hole on the starch granule surface. It was found by X-ray diffraction that both annealing and amylolysis did not alter the A type diffraction pattern. The% relative crystallinity of SANET was raised with increasing hydrolysis time and with decreasing amylose content. High performance size exclusion chromatography (HPSEC) demonstrated the decrease of the degree of polymerization (DP) of the amylose fraction of SANET after prolonged hydrolysis. For the utilization of SANET as tablet filler, it was directly compressed by a tablet compression machine at 4 kN to obtain tablets. The increased relative crystallinity of starch resulted in increased crushing strength and disintegration time, but in a decreased tablet friability. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.