Direct Synthesis of Cyclodextrin in a Heterogeneous Enzyme Reaction System Containing Insoluble Extruded Starch

Abstract

Cyclodextrin (CD) production has been mainly carried out in a homogeneous enzyme reaction system utilizing soluble liquefied starch (1,2). The shortcomings of above conventional CD production method were low CD yield and difficulties of separation and purification, due to formation of undesirable oligosaccharides (3). Direct production of CD from insoluble raw starch has distinct advantage of formation of high purity of CD without accumulation of undesirable oligosaccharides, which will facilitated purification of CDs (4,5). But raw starch exists as a compact crystalline structure, and the rate and yield of CD formation by cyclodextrin glucanotransferase (CGTase) is too low for industrial application. Therefore the structural modification of raw starch is required to increase the susceptibility to enzyme. In this work, the structre of raw starch was modified by means of extrusion, and the direct synthesis of CD in a heterogeneous enzyme reaction system containing insoluble extruded starch was attempted.