Response Surface Methodology was applied to investigate variables such as concentration of citric acid in the blanching solution, time of treatment and number of recycles of the blanching solution, which affect the acidifying blanching of pickled "Cicorino" leaves. A Central Composite Design was developed to model the variables. Results showed that the obtained models were able to provide a good estimate of the effects of individual and interactive factors on the final pH of "Cicorino". Among the considered factors, citric acid concentration is the main variable affecting sample pH value. The number of recycles did not affect in a negative way pH value providing an extension of the blanching time. (C) 2003 Elsevier Ltd. All rights reserved.