[Objective] The aim was to study on effect of maltose concentration by ultrafiltration.[Method] 40% and 15% maltose syrups were concentrated with ultrafiltration membranes at molecular weight of 6 000 Da in order to study on concentration effect of maltose and restoration effect of membranes property through backflushing.[Result] When 40% maltose was concentrated with the membrane,membrane flux weakened rapidly and pores blocked.In contrast,when 15% maltose was concentrated with the same membrane,the membra...