Effect of vegetable coagulant, microbial coagulant and calf rennet on physicochemical, proteolysis, sensory and texture profiles of fresh goats cheese

Abstract

In order to determine the technological suitability of vegetable coagulants for the manufacture of cheeses, two different aqueous extracts from cardoon (Cynara cardunculus subsp. flavescens and C. cardunculus subsp. cardunculus) and microbial coagulant (Mucor miehei) were compared with calf rennet. Optical sensors showed that the microbial coagulant had the highest clotting time (T max) whereas both rennet and vegetable coagulants had similar and lower milk clotting times. For most of the physicochemical (Colour CIELab, protein and fat) and textural (cohesiveness and springiness) parameters, no differences were observed between the different enzymes assayed. However, dry matter content, hardness, gumminess and chewiness showed significant differences, higher values being obtained in cheeses made with vegetable coagulants. As regards sensory properties, cheeses made with vegetable coagulants showed less firmness and whiteness but higher bitterness while microbial coagulant and calf rennet showed similar and higher values. No statistically significant differences were found in the soluble nitrogen or non-protein nitrogen fractions between the cheeses. The vegetable coagulants showed higher intensity bands in the Pre-αs-casein region, which was related to higher αs-casein proteolytic rates. The use of vegetable coagulants should enable manufacturers to produce fresh cheeses with new textural features, but to improve sensory profile, different technological strategies might be adopted.