RESEARCH OF RHEOLOGICAL PROPERTIES OF WATER-GRAIN SUSPENSION.

At this moment there is an aim in front of all sectors of the food industry directed on improving production efficiency to reduce capital costs on creation the ultimate quality product and optimization of the production process and the intensification of the production process. This fully applies to the brewing industry. Partially, the monopolization of the market for beer products in Russia by large foreign companies led to the reduction of beer production in our country. Fig.1 shows that since 2007 the number of manufactured products is declining.

Therefore, the establishment of mini Breweries with the use of innovation in the brewing sector and the existence of modern domestic technological equipment will help to change the situation with the decrease of beer production volumes.

The most important condition, which guarantees the successful development of mini Breweries, is the presence of universal, technological equipment on the Russian engineering market, allowing to carry out therein not one, but several stages of the process.

Originally this approach was offered by a group of researchers from the ITMO University, who offered the method of production of ethyl alcohol from starch-containing vegetative raw materials and device for its implementation [1; 3; 4]. The main goal of the proposed invention was to simplify the machine-instrumental scheme of ethyl alcohol production by the sequential performance of the basic technological stages of water-heat preparation of barley grain for fermentation and fermentation process itself in a single apparatus. The construction of shell and tube jet-injection apparatus (CSIA) has been selected as such universal apparatus. Conducted research has shown quite satisfactory results [1, 4].

Taking into account that the technologies of grain raw material preparation for fermentation for the alcohol industry and the brewing industry, to a certain extent, are close, for the improving of the machine-instrumental scheme of beer production by small businesses, was adopted the concept of combining several technological processes in one machine.

This approach to the staffing of machine-equipment schemes of brewing products production with technological equipment will significantly reduce the capital costs of organization of new small enterprises and, as consequence, reduce the time of his cost recovery, which seems the main goal at the present stage.

In turn, the development of such equipment requires theoretical and experimental studies of hydrodynamic processes in the working volume of the apparatus, as well as the study of the rheological properties of malt suspensions.

In this regard, the purpose of our work is complex, theoretical and experimental studies of rheo - and hydrodynamics of malt suspension in the working volume of shell and tube jet-injection apparatus.

Also by the employees of the Department of Processes and Apparatus of Food Production was conducted the research on change’s features of rheological properties of malt suspensions in the process of water-heat and enzymatic treatment of the grain material

The preliminary study of rheological characteristics of the malt suspensions, without the use of any enzyme preparations in the range of temperature change from 20 °C to 90 °C allowed us to obtain some general regularities of changes in the effective viscosity with the initial concentration of solid phase in suspension and the shear rate. All presented results were done on a rotational viscometer of the brand R2. The range of variation of the shear rate g was 1 ÷ -1 437,4 with.

Earlier we have conducted a comprehensive experimental study of rheodynamic characteristics of the water-grain suspensions, prepared on the basis of ungerminated barley grain [2; 5; 6; 7; 8].

As can be seen from Fig.2, the nature of the change of dynamic viscosity coefficient of malt suspension is somewhat different from the nature of the changes of dynamic viscosity coefficient of the suspension prepared on the base of barley grain.

Firstly, as expected, the values of dynamic viscosity coefficient in all the first three reference points of the viscosity-temperature curve, obtained for the malt suspension, much lower than in the corresponding points of the same curve for barley suspension. Secondly, the change of the values of dynamic viscosity coefficient in the 4th zone, is more complicated and depends on the shear rate. In particular, at low shear rate, there was the presence of a minimum value of the of dynamic viscosity coefficient for all investigated hydromodules of the water- malt suspension in the 4th district. With the increase of shear rate the intensity of increasing the malt suspension viscosity degenerates and at  = 234,6 s-1 and above, the value   remains constant for the corresponding module. It can be assumed, that such behavior of the viscosity-temperature curve is influenced by the hydrodynamic situation in the working volume of the cell resistors. It is obvious, that the local speed of the liquid phase, moving in the gap of measuring cell, affect the particles of crushed grain. The process of destruction of the molecular bonds of the grain particles and water, at low shear rates, is slower than at high rates. Taking into account the different size of the solid particles, their liquefaction occurs at different speeds. Smaller particles, typically consisting of starch grains, liquefies faster, larger particles, at the moment, still continue to liquefy. Since the time of the experiment is fixed and equal to 2000 s, it is possible, that the liquefaction process of the large agglomerates of starch grains doesn’t occur. At high shear rates, corresponding to high local speed of the suspension’s liquid component, the liquefaction process speeds up and ends during the time of the experiment.

List of references

1.         Ibragimov T.S. Improvement of machine-instrumental scheme of ethyl alcohol production: thesis … PhD.SPb.: ITMO University, 2014. 94 p.

2.            Ibragimov T.S., Chebotar A.V., Novoselov A.G. The features of changing the rheological properties of the water-grain suspense during the water-heating and ferment treatment (WHFT). – SPb.: SPb University of Refrigeration and Food Technology, The electronic scientific journal " Processes and Apparatus of Food Production", 2013, №1.

3.                   Novoselov A.G., Barakova N.V., Ibragimov T.S. Periodic method of alcohol production and shell-and-tube jet-injection apparatus used in the method: pat. 2499050 Russia. 2013. Bulletin №32.

4.                   Chebotar A.V. Improvement of alcohol production on the basis of experimental studies of reo - and hydrodynamics of water-grain suspensions in pipes of technological devices: thesis … PhD. SPb.: ITMO University, 2014.-pp. 94 - 136.

5.                   Chebotar A.V., Novoselov A.G., Petrova D.L. The influence of soaking time of crushed barley grain on the viscosity of the water-grain suspensions. // Materials of VI International conference «Refrigeration and food technology in XXI century» - SPb.: ITMO University, 2013. – pp.630- 632.

6.                   Chebotar A.V., Novoselov A.G., Petrova D.L. The influence of soaking time of crushed barley grain on the maximum viscosity of the wort in the process of water-thermal processing. – SPb.: SPb University of Refrigeration and Food Technology, The electronic scientific journal" Processes and Apparatus of Food Production" 2013, №2.

7.                   Chebotar A.V., Novoselov A.G., Petrova N.L. Study of the influence of amylolytic enzymes on the viscosity of the water-grain suspension in the process of water-heat enzyme treatment of barley grain. - SPb.: ITMO University, The electronic scientific journal" Processes and Apparatus of Food Production" 2014, №1 (17).

8.                Chebotar A.V., Novoselov A.G., Gulyaeva Y.N.       Flow of the water-grain suspensions in pipes.1. Rheological characteristics of water-grain suspensions and their change in the process of water-thermal treatment. // Innovative food technology in the sphere of agricultural raw materials store and treatment: Materials of IV International scientific. -pract. conf. 22-23 May 2014– Krasnodar, 2014, pp. 264-269.