During the enzymatic biotransformation of lactose to galactooligosaccharides, complex saccharide solutions are generated. In most cases, solely a fraction of these saccharides is desired. Therefore, four industrial relevant nanofiltration membranes were tested regarding their suitability to fractionate mono- and disaccharides. The most promising membrane was selected for further experiments. With this membrane additional parameters, namely transmembrane pressure difference dpmf, filtration temperature (sic) and saccharide concentration c(S), were varied under steady state conditions. Saccharide concentrations in all retentate and permeate samples were analyzed by HPLC-ELSD. The criteria of flux J, rejection R-S, solute flux J(S), fractionation purity Delta R-S and efficiency QJ(S) were evaluated in a complex food matrix at an industrial relevant scale. The interaction between Delta p (TM) and (sic) and their influence on Delta R-S and QJ(S) was further investigated by performing a multiple linear regression analysis with a quadratic model. The results suggest that for the chosen membrane and saccharides, trade-offs between purity and efficiency are necessary depending on the overall aim of the process. In the case that high purities need to be achieved, combinations of either low pressures and temperatures or high pressures and temperatures are promoting, while only increasing one parameter decreases the purity of the fractions. In order to achieve a high process efficiency high pressures are promoting.