Cheesemaking with plant coagulants obtained from local wild flora of Marche region

ABSTRACT The aim of this doctoral thesis was to characterize the technological properties of the proteases found in raw aqueous extracts (CE) from wild flora of the Marche region, (Carlina achantifolia All.Subsp. Achantifolia). Microbiological dynamics, physico-chemical parameters, and volatile components (aroma) of cheese (“Caciofiore della sibilla”) obtained by using vegetable coagulants, were also studied. CE prepared from separate anatomical parts of the thistle plant were compared with calf rennet and tested at different temperatures, concentrations of CaCl2 and storage conditions. Analyses showed that the calf coagulant had the highest milk clotting activity (MCA) whereas vegetable coagulants had lower milk clotting times. The optimal MCA of CE was observed at a temperature of 55-60 °C. MCA of the flower extracts was greater than that of the stems. Addition of CaCl2, in the range of concentration experimented, had a positive effect on the clotting activity of extracts. The amount of enzymes (CE) used was very discriminating for MCA. Storage at -20 °C had no effect on MCA. The volatile components of the aqueous extracts obtained from Carlina achantifolia All. and of the cheese sampled different times of ripening were also quantified and partially identified by SPMEGC- MS. The number of volatile compounds identified in the flower aroma were greater than the stems. Many compounds identified in the early stages of the ripening were not detected in the final product. Other compounds were identified in all cheese samples but exhibited higher levels in the ripe cheese . The impact of vegetable rennet on bacterial dynamics and on the overall diversity showed a great difference in the bacterial composition in the cheese while the contribution of the vegetable coagulant to the cheese fungal diversity had a marginal or no contribution.