Production of glucooligosaccharides and polydextrose by extrusion reactor

Glucose mixed with citric acid as a catalyst was extruded and polymerized using twin screw extruder with 40 of L/D (length/diameter) ratio at 160, 180 and 200°C, where the polymerization yields of glucose were 43.9%, 75.0% and 93.7%, respectively. Gel permeation chromatography of glucose extradates showed that the higher molecular weight fractions increased with extrusion temperature, which also resulted in increasing hydrodynamic intrinsic viscosity. Glucooligosaccharide and polydextrose produced by extrusion of glucose were stable for thermal treatments over a wide range of pH 3.0-11.0. In addition, a-amylase and amyloglucosidase treatment did not affect the solution viscosity, indicating the random linkages of glucose and thus the potential applications as dietary fiber. This research clearly demonstrated that the extrusion reactor can be successfully utilized to produce glucooligosaccharide and polydextrose from glucose rapidly and continuously in conjunction with selective control of polymerized composition.