ABSTRACT
Induced mutagenesis with y-irradiation of the industrial strain Bacillus licheniformis-60 VKM B-2366,D was used to obtain a new highly active producer of an extracellular serine protease, Bacillus licheni- formis7 145. Samples of dry.concentrated preparations of serine protease produced by the original and mutant strains were obtained, and identity of their protein composition was'established. Alkaline serine protease sub- tilisin DY was the main component of the preparations. The biochemical and physicochemical properties of the Protolkheterm-145 enzyme preparation obtained from the mutant strain were studied. It exhibited pro- teolytic activity (1.5 times higher than the preparation from the initial strain) within broad ranges of pH (5- 11) and temperature (30-70'C).-Efficient hydrolysis of extruded soy meal protein at high concentrations (2 to 50%) in-the reaction mixture was.the main advantage of the Protolikheterm 145 preparation. Compared to,. the preparation obtained using the initial strain, the new preparation with increased proteolytic-activity pro- vided for more complete hydrolysis of the main non-nutritious soy,proteins.(glycinin and 0-conglycinin) with the yield of soluble protein increased by 19-28%, which decreased the cost of bioconversion of the protein- aceous material and indicated promise of the new preparation in resource-saving technologies for processing soy meals and cakes.
Subject(s)
Bacillus licheniformis/radiation effects , Bacterial Proteins/chemistry , Globulins/chemistry , Glycine max/chemistry , Soybean Proteins/chemistry , Subtilisins/chemistry , Antigens, Plant/chemistry , Bacillus licheniformis/enzymology , Bacillus licheniformis/genetics , Bacterial Proteins/biosynthesis , Bacterial Proteins/genetics , Bacterial Proteins/isolation & purification , Enzyme Stability , Gamma Rays , Gene Expression , Hydrogen-Ion Concentration , Hydrolysis , Kinetics , Mutagenesis , Seed Storage Proteins/chemistry , Subtilisins/biosynthesis , Subtilisins/genetics , Subtilisins/isolation & purificationABSTRACT
The data of the literature on the impact factors of the extrusion cooking on physical and chemical properties of food proteins, biological value and digestibility have been discussed. Extrusion cooking is a high temperature short-time process, characterizing by a minimal loss of nutrients. and biologically active substances compared to other methods of heat treatment of food. Studies of the properties of protein-containing products, protein isolates and concentrates in the extrusion are examined in different ways: the inactivation of antinutritional factors; improvement in digestibility and availability; changes in the content and chemical modification of amino acids; Maillard reactions involving amino acids; mutual enrichment of protein mixtures during the composite food extrusion; formation of functional technological properties of the extruded protein products.
