Valorisation de fleurs de cardon algérien

Abstract

This study aims to promote traditional Algerian practices and the socio-economic valorization of spontaneous the Algerian cardoon (Cynara cardunculus var sylvestris) and the cultivated one (Cynara cardunculus var atlilis), exploring the use of proteases contained in their flowers as coagulants intended for the dairy industry. The work was carried out by comparison to a Portuguese control variety and subdivided into four main parts: 1) the purification and biochemical characterization of cardosines, 2) the study of milk clotting and biochemical characteristics of the coagulums obtained, 3) the artisanal manufacture of a Portuguese cheese monitoring the evolution of its qualities and a study on the possibility of preservation of cardoon flowers by drying. The raw extracts obtained from the two Algerian varieties (Cynara cardunculus var sylvestris et Cynara cardunculus var atlilis) showed contents of cardosins up to 70.57% and 62.15% of the total proteins for spontaneous and cultivated cardoon while a content of 42.12% was obtained for the control variety. The purification protocol carried out allowed separation of three types of cardosins (A0, A and B) from the Algerian varieties, that have been documented. All the cardosins studied are dimer heteroproteins consisting of two large and small chains. Cardosins from the two Algerian varieties differ from those of the Portuguese variety by shorter elution times, higher molecular weights, lower glycosylation levels and non-identical amino acid chains. The study of specificity with respect to kappa casein and the β chain of oxidized insulin did not reveal significant differences between varieties. Measuring coagulating properties and theoretical cheese yields revealed a good ability of our Algerian cardosins to coagulate milk. The coagulums obtained by our cardosins depicted various rheological behaviors offering a wide possibility of their application for the manufacture of different types of cheeses. The use of Algerian spontaneous cardoon flowers in the manufacture of Portuguese DOP cheese type Serra Da Estrella has allowed the production of a cheese very similar to the control. Flower drying tests have shown that the application of temperatures between 50 and 55 degrees Celsius leads to enzymatic and technological profiles closest to those of fresh flowers. Overall, our findings confirm the possibility of using flowers from spontaneous or cultivated Algerian cardoons as a coagulant in cheese making. The valorization of this crop by the production of its coagulants may be economically beneficial and could be a good alternative to reduce importations and support the national market.