CHOICE OF STABILIZATION PARAMETERS (FREEZING AND DRYING) OF SYMBIOTIC CONSORTIUM TO OBTAIN A STARTER OF DIRECT INOCULATION

An important component in the production of starters for food and biotechnology industries is the ability to store them over a long period without losing their properties. Long-term storage of biological products with the conservation of valuable properties and viability can only be ensured by methods of preservation which are able to inhibit metabolic processes without disturbance to biomaterial integrity. The article describes methods of deep-freezing of biomaterials, freeze-drying, L-drying, in particular their advantages and disadvantages, and gives more concrete description of the lyophilization method. The aim of this research was to choose a method of drying and optimum stabilization parameters for obtaining a starter of direct inoculation. To do this, freeze-drying method allowing the primary cell structure to be fully preserved was used. The experiment indicated that this method makes the object of drying independent from external influences and is able to retain its useful properties over a long period of time. The drying process itself was carried out using domestic freeze-drier INEY-6M". To prepare the drying object for lyophilization bacterial cells were suspended with 20% skimmed milk, 12% solution of sucrose, the serum of animal blood, sorbitol, albumin solution, gelatin solution, peptone, monosodium glutamate and its salts, polyvinylpyrrolidone. The choice of optimum modes of technological process such as freeze temperature, freeze-drying temperature and drying layer thickness was also carried out experimentally. According to the results of the experiment, optimum parameters for freeze-drying were chosen, in particular: freezing temperature of minus 25°C; heating temperature of 25°C; drying time of 240 min; the drying layer thickness of 3.0 mm.