Effect of temperature and agitation on the enzymatic synthesis of oligosaccharides and dextran in orange juice

Abstract

The production of prebiotic fruit juices has been extensively investigated, mainly by the enzymatic route. However, studies involving agitated reactors and other important parameters are lacking. This work evaluated the effect of temperature and agitation on the synthesis of oligosaccharide and dextran in orange juice using dextransucrase. The syntheses in orange juice were carried out in magnetic and mechanic stirred-tank reactors at 25 (MAG25, MEC25) and 30°C (MAG30, MEC30) for 24 h. A low final sucrose concentration was found at 6h for magnetic stirring and low temperatures. The reducing sugar concentration decreases at 25°C and increases at 30°C throughout the process. Results showed higher oligosaccharide and dextran production at 25°C. Magnetic agitation (MAG) favored the dextran synthesis over the mechanic agitation (MEC) at the same temperature. MAG25 and MEC25 provided similar concentrations of oligosaccharides at 6h. Although MAG25 and MEC25 were the best conditions to synthesize oligosaccharides and dextran in orange juice, MEC25 is more suitable and feasible for large-scale production.