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The actual challenge for the food industry is the utilization of by-products of fruit and vegetable processing and their use in the production of enriched food products. It allows to use raw materials with a high content of biological active substances more efficiently and rationally. The possibility of using carrot bagasse as an ingredient in the preparation of extruded ready-to-eat product was studied. The wheat meal was used as core ingredient. The influence of the bagasse dosage on the extrusion conditions and the properties of the extrudates samples was studied. It was shown that an increase of the bagasse content more than 20% influenced the quality of the product negatively.The expansion index decreased more than 2 times and the bulk density increased by 40%. The method of additional steam venting from the middle part of the extruder chamber was investigated during the extrusion cooking of mixtures with the bagasse content more than 20% and moisture content 26.5, 28.9 and 34.5%.The indicator of the steam venting was the reduction of pressure in the degassing installation. As a result, the moisture content of the material in the die zone of the extruder chamber decreased. It was shown that additional steam venting during extrusion of high-moisture mixtures led to more severe extrusion conditions. The temperature, die pressure and torgue increased significantly. It imroved the quality of extrudates. Steam venting during extrusion of blends with 26.5 and 28.9% moisture increased expansion index more than 2 times and decreased the bulk density by 21-25%.Extrusion process of a mixture with a moisture content of 34.5% without and with steam venting was unstable and did not allowed to obtain samples of extrudates with acceptable quality. The proposed method for extrusion of high-moisture blend of wheat flour with carrot bagasse can be basis for developing technologies for the production of ready-to-eat extruded products using moist food by-products of fruits and vegetables processing.

The influence of the mixing factor and its intensity was investigated at the stage of developing a technology for processing highly concentrated hydrolysates (50% solids) of extruded corn starch. The starch was extruded using a twin-screw extruder at a temperature of 185 °C and a pressure at the die of 2 MPa. Extruded substrate was hydrolyzed with enzyme preparations of ?-amylase and glucoamylase for 4 hours with different stirring modes. The significance of the stirring speed on the degree of hydrolysis of extruded starch, especially in the first 2 hours of enzymatic treatment, has been established. As a result of 4-hour exposure, the dextrose equivalent of the hydrolyzate incubated without stirring was 52.2. Dextrose equivalent of the hydrolysates stirred at speed of 100, 200 and 500 rpm was 54.5, 59.3, and 59.8, respectively. The study of rheological properties showed that the dynamic viscosity of a medium without stirring significantly differed from the viscosity of a medium with stirring throughout the entire hydrolysis period. As a result, the dynamic viscosity of the sample without stirring and with stirring decreased from 3 Pa?s to 0.35 Pa?s and from 2.5-2.8 Pa?s to 0.145-0.221 Pa?s, respectively. An double increase of the glucoamylase dosage made the mixing factor after 4 hours of hydrolysis insignificant and increased the dextrose equivalent value by 18-35%. The dextrose equivalents of samples without stirring and with stirring at a frequency of 200 rpm were 70 and 71, respectively. But in the first 2 hours of hydrolysis, the stirring factor for samples with an increased dosage of glucoamylase was also statistically significant. The study showed that hydrolysis of highly concentrated media of extruded starch under the condition of high-quality homogenization with the enzymes provides a high degree of bioconversion without the requirement for continuous mixing,

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Increase of solubles concentration in processable liquid media is one of the trends of technological development of starchy materials bioconversion. It promotes the reduction in operating costs, in heat and energy consumption and increases the efficiency of using capacitive equipment. The use of thermoplastic extrusion in the bioconversion processes as a pretreatment stage is perspective. Extrusion provides intensive gelatinization of starch with a moisture content of 15-30 % that has become a prerequisite for the development of extrusion-hydrolytic technology for obtaining of concentrated hydrolysates from starch-containing raw materials. As a part of the technology development, the effect of the key factors of biocatalysis on the formation of hydrolysis products and the rheological properties of highly concentrated hydrolysates of corn starch has been studied. The dosage of thermostable α-amylase and the concentration of the medium were taken as independent variables. The ranges of variation of the factors were set in the range of 5-13 units of amylolytic activity per 1 g of starch and 40- 60 % soluble concentration in accordance with the central orthogonal second-order design of the experiment. The value of dextrose equivalent in the area of the studied factor space varied from 23 to 40. Dynamic viscosity values were in the range from 89 to 2219 mPa·s. The analysis of the results and the mathematical model showed that an increase in the dextrose equivalent in the hydrolysis products was facilitated by a decrease of the concentration of the medium and an increase in the dosage of α-amylase. The growth dynamics of the dextrose equivalent value decreased with an excess of the dosage of the enzyme preparation of 9 units of amylolytic activity per 1 g of starch. Rheological studies have shown that a dosage of α-amylase of 1- 13 units of amylolytic activity per gram of starch at 40 % concentration of the medium provided dynamic viscosity values in the range 89-780 mPa·s, which is sufficient for the subsequent stages of hydrolyzate processing. Increasing the concentration to 50-60 % requires the introduction of α-amylase at a dosage of more than 5 units of amylolytic activity to ensure a rheologically safe process.