La coagulation du lait par l’extrait des fleurs de cardon (Cynara cardunculus).

Abstract

The aim of the present work is the preparation and the characterization of the cardoon flowers (Cynara cardunculus) extract, as well as the study of its potential use as a calf rennet substitute. The work consisted of the coagulant agent extraction from flowers locally harvested, and of the characterization of the enzymatic extract obtained. The comparison between the cardoon floral extract and calf rennet, by studying its proteolytic activity and by approaching the interaction types implied in the gel formation. And finally the realization of production trials of a Brie type soft cheese and Camembert type in two local unites of cheese making. Extraction diagram used allowed to have a coagulant extract containing mainly cardosines A and B. One milliliter of the prepared extract presents a coagulant activity of 3.23 UP and a power of 1/888. The optimum of its activity is noticed at pH 5, at a temperature of 60°C and at a CaCl2 concentration of 0/02 mole/liter of milk. The proteolytic activity of this extract is nearly the double of the calf rennet. The study of interactions showed the importance of the hydrophobic, hydrogenic and calcic bonds in the cardosine gel formation. Soft cheeses obtained with cardoon flowers extract present a better organoleptic quality, however, the yield is relatively weak. Thus, we suggest the possibility of the substitution of calf rennet with cardoon flowers extract in the manufacturing of cheese, meanwhile considering the study of means for promoting a better cheese yield.