A preliminary study of continuous milk coagulation using Cynara cardunculus flower extract and calf rennet immobilized on magnetic particles

- Calf and vegetable rennets were covalently immobilized on magnetic carriers.
- Optimal pH and temperature of both immobilized coagulants, shifted respect to the free forms.
- In a bench-scale bioreactor immobilized coagulants carry out a continuous milk coagulation.

The aim of this study was to develop a bioreactor design for continuous milk coagulation using a biocatalyst composed of immobilized animal and vegetable rennet on aminated magnetic particles, which has been proven to be an appropriate carrier for enzyme immobilization. Calf and vegetable (Cynara cardunculus) rennets were covalently immobilized on CLEA® magnetic supports and the immobilization procedure was optimized in batch mode, by evaluating protein loading, caseinolytic activity and the coagulation properties of skim milk powder and cow's milk. Subsequently the optimal temperature of immobilized coagulant was defined and a technically-friendly enzyme bioreactor was developed in order to carry out a continuous milk coagulation process with the aim of producing soft cheese.