Technological characterisation by free zone capillary electrophoresis (FCZE) of the vegetable rennet (Cynara cardunculus) used in “Torta del Casar” cheese-making

The purpose of this work was to develop a procedure based on protein analysis by free zone capillary electrophoresis (FZCE) that can be used as an alternative to other methods in the determination of the technological quality of vegetable rennet to use in “Torta del Casar” cheese-making. Samples of cardoon flowers (Cynara cardunculus) grouped according to location, harvest year, and ripening stages were used in the study. For the FZCE, a protocol for extracting the methanol-soluble proteins was tested. This method was found to give good repeatability of the corrected migration time (CMT), and showed higher effectiveness in discriminating the technological properties (milk-clotting and casein degradation activities) of vegetal rennets than the SDS–PAGE technique. In addition, three peaks found in the FZCE electropherograms were examined as a good tool to predict the impact of vegetable rennet on the creaminess and overall acceptability of the “Torta del Casar” cheese.