Effect of high pressure on isomerization and degradation of lactose in alkaline media

The combined effects of temperature (60 °C) and high-pressure treatments (400 MPa for 3 h) on the isomerization-degradation of lactose (10%) in basic media were studied. The formation of isomeric disaccharides (lactulose and epilactose) and galactose decreased by the application of high pressure in aqueous sodium hydroxide 4 mM (pH 10.2) and 8 mM (pH 10.6), and sodium carbonate-bicarbonate buffer (pH 10.0). In addition, no substantial color development was observed in the sodium hydroxide systems for high and atmospheric pressure, whereas the application of high pressure led to a noticeable decrease of color development in the carbonate-bicarbonate system.This work was supported by the Comisión Interministerial de Ciencia y Tecnología (C.I.C.Y.T.) Project AGL2001-1971 and AGL2000-1497.Peer Reviewe