Caseinolytic activity expression in flowers of Cynara cardunculus L

Flowers of wild cardoon [Cynara cardunculus L. subsp. sylvestris (Lamk) Fiori] represent a milk–clotting agent for production of typical cheeses in some countries (Portugal, Spain, Morocco, Italy). Considering that during the production of globe artichoke [Cynara cardunculus L. subsp. scolymus (L.) Fiori], a number of small unmarketable heads are left in the field, it has been proposed to utilize these for Sicilian cheese production. The aim of the present research was to evaluate the total caseinolytic activity and coagulating strength of globe artichoke flowers (cv. ‘Violetto di Sicilia’) compared with those of flowers of 3 wild cardoon ecotypes collected in different areas of eastern Sicily (south Italy). Such activity was evaluated on samples of ovine, bovine and caprine milk. Globe artichoke showed a high caseinolytic activity (0.46 U mg-1), but a low coagulating strength (71 Soxhlet Unit); within the three ecotypes of wild cardoon, S. D. Vittoria accession presented the highest caseinolytic activity (0.45 U mg-1) and coagulating strength (135 Soxhlet Units). The milk–clotting activity was highest at pH 6 and with no NaCl. Regardless of the studied genotypes, caprine milk showed the highest coagulating strength. Results obtained could represent the basis for further researches focusing on the integral utilisation of globe artichoke, above all aiming to valorise the waste biomass.