Influence of Type of Substrate and Enzyme Concentration on Formation of Galacto-oligosaccharides

Different substrates and different concentrations of enzyme (Maxilact LX 5000) for galacto-oligosaccharides synthesis were tested. Lactose in phosphate buffer (138 mmol/l), ultrafiltration permeate (115 mmol/l), recombined whey (136 mmol/l) were used as substrates. Concentrations of used enzyme were from 0.15 to 15 U/ml for lactose in buffer, from 0.12 U/ml to 1.5 U/ml for ultrafiltration permeate and 1.5 U/ml for recombined whey. Reaction products were analysed by HPLC. There was obtained 6.4 +/- 0.4 mmol/l of galacto-oligosaccharides (GOS) for lactose in buffer, it means that 0.0633 +/- 0.0025 g/g of lactose was converted to GOS. The conversions of lactose to GOS for recombined whey and ultrafiltration permeate were 0.0669 +/- 0.0079 and 0.0920 +/- 0.0010 g/g. There was obtained 7.3 +/- 0.1 mmol/l of GOS for ultrafiltration permeate and for recombined whey 5.9 +/- 0.1 mmol/l of GOS.