Mineral fortification modifies physical and microstructural characteristics of milk gels coagulated by a bacterial...

An enzymatic pool from the Amazonian bacterium Bacillus sp. P7 was used as milk coagulant. Discovery of novel coagulants is of great interest in dairy industry for the development of new textures in cheese. Color, mechanical and microstructural characterization of milk gels induced by the bacterial enzymatic pool was carried out. Effect of mineral fortification on these characteristics was studied. Whiter gels with smaller pore diameters were obtained in the presence of Ca²⁺ or Mg²⁺. These characteristics seemed to be influenced by the effect of ionic strength on casein structure which was also evidenced by digital texture features analysis. On the other hand, specific affinity of the assayed cations for milk proteins showed to be important in the development of the mechanical texture of the gels. Firmness and fracture force of milk gels obtained in the presence of Zn²⁺ or Ca²⁺ were higher than in the presence of Mg²⁺ and Na²⁺.