BACKGROUNDThe isomerization of glucose to fructose is one of the most widely used processes in the food industry to produce dietetic foods and drinks. Since this reaction is affected by external mass transfer resistances, application of an impinging jets technique in reducing external resistances may be justified. RESULTSConversion of glucose to fructose was studied in a novel type of impinging streams reactor using glucose isomerase enzyme. Response surface methodology was applied to determine the effects of certain pertinent parameters of the process including axial velocity (A), feed concentration (B), nozzle flow rates (C) and enzyme loading (D) on the performance of the apparatus. A quadratic polynomial multiple regression model was selected and analysis of variance revealed a high coefficient of determination (R-2) value equal to 0.972. The optimum process conditions for fructose production were established as, A = 0.1 m s(-1), B = 1.5 kg m(-3), C = 3.3e-5 m(3) s(-1) and D = 0.0035 kg. CONCLUSIONIt was found that an impinging streams reactor had higher performance capability in comparison with conventional reactors in solid-liquid enzyme reactions. In such a reactor 30% conversion of glucose was obtained within 9 s while the same conversion in packed-bed reactors requires 5 min. (c) 2013 Society of Chemical Industry