Study of the impacts of the starter cultures composition on the physical-chemical properties in the biotechnology of cheese making

Ways to improve assessment of physical-chemical properties of starter cultures in cheese making are discussed. According to the concept of structure formation certain connection exists between rheological properties of starters, rennet coagulum and rennet cheese. That’s why effects of the starter type on the changes of acid coagulum are of great importance. Effective viscosity was determined for the commercial starter of mesophilic streptocci and mesophilic lactococci of the Lithuanian Food Institute, starter of special composition from thermophilic lactococci and lactococci, starter of monoculture of Lbm. helveticus 19. Rate characteristics of viscosity were analyzed using the Osvaldde -Will equation. Shear rate increase leads to the sharp decrease of viscosity, and this can be explained by partial destruction of the structure. When shear rate becomes lower the rate of viscosity change depends on the gradient rate in the less degree. The system was destroyed to less degree than when rate gradient increased. Ticsotropic properties of the starters were evaluated by the Green-Grace method. It was established that high level of ticsotropicity was characteristic for all the types of starters. After mechanical destruction the protein coagulated system restored its structure well enough. It was found that changes of the starter micro ora considerably effect rheological product of the starter. High viscosity of the coagulum promoted improvement of cheese consistency.

cheese making, starters, physical-chemical characteristics