RU2303369C2 - Method for inactivating antinutritive substances and increasing nutritive value of soybeans - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: the present innovation deals with the technology for manufacturing soybean products. At the first stage the whole beans at own moisture should be heated with hot dry air of 180-200°C up to 95-100°C/sec due to the impact for about 1-2 sec with UHF field at specific power being 35 kW/kg, not less at the intensity of electric constituent of electromagnetic field being 200 V/cm, not less followed by keeping soya for about 20-30 sec in UHF level-descending field without temperature changes. The innovation enables to improve the quality of ready-to-use product at decreased labor capacity and energy expenditure during the process of soybean treatment.

EFFECT: higher efficiency of inactivation.

4 ex, 1 tbl

Description

The invention relates to a technology for the production of soy products, which can be used in the confectionery, meat and dairy and baking industries as high-protein ingredients and stand-alone products, as well as in the production of highly effective animal feed.

A known method of processing non-fat soya beans (RF Patent RU 2038797, A23K 1/00, A01F 25/00, A23N 12/00, published 09.07.95), which allows to increase the nutritional value of soybeans and reduce the content of anti-nutritional substances to a safe level. The method is based on soaking the beans in water for at least 3 hours. Surface moisture is removed by passing through the mass of an air stream and microwave processing at a temperature of the mass of beans 90 ° C to a residual moisture content of 7%, followed by cooling the beans to ambient temperature.

A known method of inactivation of anti-nutritional substances of soybeans (RF Patent RU 2057464, А23L 1/211, publ. 04/10/96), which provides for washing whole soybeans with water, soaking them in an alkaline solution with a pH value of 8.3-8.5 to the degree swelling of 0.3-0.35 and heat treatment in the field of microwave currents at a temperature gradient of 7-9 ° C for 1 minute to a soybean moisture of 8-12%.

There is also known a method of producing oilcake and oil from soybeans (RF Patent RU 2232799, СВВ 1/00, publ. 04.11.2002), including moisture-heat treatment of russel with a moisture content of 7-20% in an electromagnetic field of a microwave range with a specific power of 0.2-2 , 0 kW / kg for 1-6 minutes and thermoplastic extrusion.

Known methods can reduce the activity of trypsin inhibitors to acceptable values, and the urease pH to zero, but do not provide a high-quality product due to a residual bean or alkali flavor, in addition, protein denaturation or degradation occurs due to the long processing time in A microwave field, which impairs its digestibility or reduces its amount.

These known methods involve cyclic processing of the product, are labor-consuming and energy-consuming, require special equipment for soaking and washing the beans, additional costs for the disposal of industrial waste containing substances that pollute the environment.

The closest in technical essence and the achieved result to the proposed method is a method of heat treatment of grain products by electrophysical methods (RF Patent RU 2085088, А23L 1/18, publ. 27.07.97), which includes two stages of processing. At the first stage, the product is heated for 30-90 s with thermal energy, for example, infrared energy, to a temperature of 95-105 ° C without a significant change in its moisture content. In the second stage, lasting 20-60 seconds, the product temperature is brought to 120-180 ° C using a microwave electromagnetic field with a specific power of at least 5 kJ / kgf. This method has the ability to inactivate soy inhibitors without soaking and cooking, but a high final processing temperature of 180 ° C leads to protein denaturation, oxidation of the native oil, and deterioration of consumer properties of soy.

The aim of the invention is to improve the quality of the finished product, reducing the complexity and energy consumption of the processing process.

The technical result of improving the quality of the finished product consists in the destruction of urease and trypsin inhibitor, in improving the nutritional properties of soy due to a deeper conversion of starch into an easily digestible form, reducing labor intensity and energy consumption - in the continuity of the processing and use of one type of energy - electrical energy, converted into thermal and microwave energy.

This goal is achieved by the fact that in the known method of heat treatment of grain products by electrophysical methods (RF Patent RU 2085088, А23L 1/18 publ. 07.27.97), which includes the processing of grain with heat energy in the first stage and microwave energy in the second, in the first stage beans with their own humidity are heated with dry hot air with a temperature of 180-200 ° C to a temperature of 95-100 ° C, at the second stage they provide a temperature gradient of 10-15 ° C per second by exposure for 1-2 seconds with a microwave field with specific power not less than 35 kW / kg with voltage the electric component of the electromagnetic field of at least 200 V / cm, followed by exposure for 20-30 seconds in a decreasing microwave field level without changing the temperature.

The proposed method of inactivation of anti-nutrients and increase the nutritional value of soybeans is as follows.

Bean processing is carried out in two stages.

Soybean of its own moisture enters the processing without preliminary wetting. At the first stage of processing by continuous blowing with dry hot air at a temperature of 180-200 ° C, evaporation of moisture from the surface of the beans is provided above the speed of its movement from the inner layers. This allows you to dry the surface layer of beans, increase the mobility of water molecules in capillaries and bean cells, bring its temperature closer to the boiling point, and obtain a partial pressure inside the capillaries that exceeds the coolant pressure. When the temperature of the beans reaches 95-100 ° С, the soybean is moved to the second processing stage, which consists in exposing the moving soybeans to a microwave field with a specific power of at least 35 kW / kg and an electric component of the electromagnetic field of at least 200 V / cm within 1-2 seconds, providing a temperature gradient of 10-15 ° C in one second, with this, structural changes of the grain, the destruction of low molecular weight proteins, the conversion of starch into an easily digestible form and as soybeans move in with adayuschem by level exponentially microwave field for 20-30 seconds at a constant temperature occurs fastening beans achieved processing results. After warming the soybeans to a temperature of 95-100 ° C at the first stage, soybean processing is carried out with continuous movement. The continuous processing mode allows you to bring the second processing stage as close as possible to the first, this contributes to the conservation of heat received by the soybeans in the first stage when it enters the second stage, and therefore, reduces energy consumption in the second processing stage. Processing conditions can be supported by the speed of movement of soybeans and the temperature of hot air in the first stage of processing.

The established ranges of regime parameters of the proposed method of inactivation of anti-nutrients and increase the nutritional value of soybeans are due to the following factors.

The use of dry hot air with a temperature of 180-200 ° C at the first stage of processing allows obtaining the temperature of beans 95-100 ° C for the optimal time (1-2 min) with the optimal moisture content and distribution in the grain (9-10%). At air temperatures below 180 ° C, the rate of removal of surface moisture decreases and, accordingly, the heating time of the beans increases, which reduces the efficiency of the process due to heat loss to the environment, the degree of denaturation of the beans increases, and partial pressure inside the capillaries cannot be obtained above the coolant pressure. Air temperature above 200 ° C leads to burnout of the upper layers of the grains. Heating soybean grain to a temperature below 95 ° C leads to an increase in energy consumption in the second stage, which significantly reduces the efficiency of the method. Heating the beans to temperatures above 100 ° C leads to the redistribution of moisture in the caryopsis, its boiling in capillaries, the low rate of vaporization and the increase in excessive pressure of free moisture leads to an increase in the denaturation of proteins, and with prolonged exposure to a decrease in their solubility (F.D.Bratersky. Grain Enzymes, Moscow: Kolos, 1994, 196 pp., P. 137), therefore, the duration of the first processing stage was determined experimentally and was 1-2 minutes, while the humidity of the beans was 9-10% - optimal conditions for obtaining high-quality indicators of the finished product after the second stage of processing at high process efficiency.

The microwave treatment at the second stage provides intensive volumetric heating of the beans, affecting the internal free and bound moisture, due to which there are structural changes in the caryopsis in two directions - a sharp increase in pressure in the cells, overpressure in the pores and capillaries, and a situation arises when the expiration time liquid and vapor from the capillaries longer than the heating time, a thermal explosion occurs, as a result of which the cells of the kernel are destroyed (V.M. Kononov, A.F. Nosovets. Theory of micronization of grain by microwave energy I. Issues of Special Radioelectronics. Series: General Issues of Radio Electronics. Issue 1. Moscow-Taganrog, 2003, p.146.), low molecular weight proteins, which include trypsin, chymotrypsin and other protease inhibitors, molecular CH bonds are broken in raw starch, starch is converted to an easily digestible form - dextrin, which increases the nutritional value of soybeans. At the same time, soy deodorization occurs, the bean taste disappears, pathogenic microorganisms and fungi are destroyed.

The level of specific power of the microwave electromagnetic field is determined experimentally and should be at least 35 kW / kg with an electric component of the electromagnetic field of at least 200 V / cm to obtain a temperature gradient of 10-15 ° C per second, which provides for 1- 2 with a deep conversion of starch, the complete destruction of anti-nutritional substances.

The gradient of temperature growth below 10 ° C per second does not provide complete opening of starch granules and obtaining a high degree of dextrinization. A gradient of temperature increase above 15 ° C per second leads to an increase in the level of gelatinization of starch, to the burnout of sugars, to the degradation of protein and the deterioration of the quality of the finished product. The duration of exposure to a high power level of more than 2 seconds leads to a sharp increase in the final processing temperature, therefore, to enhance factors that worsen the quality of the finished product.

Exposure to soybeans in a falling microwave field for 20-30 seconds, at which the final temperature of the second processing stage is maintained, ensures that the obtained qualitative and quantitative changes in the beans are fixed.

The use of electric energy as the basis for the production of thermal and microwave energy allows the process to be implemented without the use of other energy sources (steam, gas, etc.).

The proposed method of inactivating anti-nutritional substances and increasing the nutritional value of soybeans has all the signs of a continuous technological process and can be easily automated.

When developing the method, soybeans of conditioned intrinsic humidity of 12-14% were processed by known methods, the results were compared with the results of the proposed one.

Example 1. Soybean was treated with a moisture content of 12-14% by extrusion using a serial press extruder KMZ-2U. The temperature of the soybean at the exit of the extruder was 130 ° C.

Example 2. The same soybeans were treated with infrared energy using quartz halogen lamps. The temperature of soybeans amounted to 130 ° C, a further increase in temperature leads to the burning of the surface of the beans.

Example 3. The same soybeans were processed in the microwave field of the Electronika household microwave oven for 15 minutes, while the soybeans were heated to 140 ° C, increasing the processing time leads to charring of the beans.

Example 4. The same soybean was processed by the proposed method on the basis of an industrial microwave source with a power of more than 3 kW, an electric heat gun and standardized metrological equipment placed in a vertical type installation consisting of: a loading hopper with a heat exchange device in the form of mesh cases connected to microwave input; Microwave camera, consisting of the processing area of soybeans by microwave energy and the amount of exposure of soybeans; a metering device connected to the output of the microwave camera.

The proposed method of inactivation of anti-nutrients and increase the nutritional value of soybeans was implemented as follows.

Pre-cleaned soybeans of their own moisture were fed into the loading hopper, further soybeans moved by gravity, from top to bottom, into the heat exchanger between the mesh housings, through which hot air was blown with an electric heat gun, where the soy was heated as it moved, and at the exit of the heat exchanger its temperature was 95-100 ° C. Then, the heated soybean by gravity entered the microwave chamber, where during the movement in the processing area it was exposed to microwave energy, and for 25 seconds it was in the decreasing microwave field level, while the temperature of the soybean was maintained due to the thermal insulation of the chamber on the level of 125-130 ° C, achieved at the exit from the processing area. From the output of the microwave camera, soybeans through a drum-type dispenser entered the discharge hopper.

The processing was carried out in normal climatic conditions, the air temperature at the outlet of the electric heat gun was 190 ° C. The parameters of exposure to microwave energy were provided by the design and dimensions of the microwave camera, the power of the microwave generator, and the speed of soybean movement. The speed of movement of soybeans was regulated by changing the number of revolutions of the dispenser.

A comparative assessment of the known and the proposed method was carried out on nine main indicators. The indicators were determined by a regional specialized laboratory using well-known methods. The specific energy consumption was obtained by calculation as the ratio of the power consumed by the equipment to their productivity. The results are shown in the table.

The experimental results show that the proposed method of inactivating anti-nutritional substances and increasing the nutritional value of soybeans provides, in comparison with the known ones, a significantly higher quality of the final product, lower specific energy costs and processing costs.

Table Indicators Source product Processing methods Extrusion IR processing Microwave oven "Electronics" The proposed method Urease activity, pH, GOST 13979.9-69 2.1 0.2 0.05 0.1 0.01 Protein,%, GOST13496.4-93 28,4 - - - - Protein,%, GOST13496.4-93 - 41.5 37.5 38.3 42.3 Oil content,%, GOST10857-80 19.3 17.3 16.5 17.5 19.3 The acid number of the oil, mg KOH, GOST5476-80 3.4 5.2 5,4 6.1 3.38 Starch,%, GOST10845-80 12.16 - - - - Mass fraction of water-soluble carbohydrates,%, GOST 51636-2000 2.6 5,6 3.8 4.6 13.5 Nitrates, mg / kg GOST13496.19-93 75 71 72 69 56 Nitrites, mg / kg GOST 13496.19-93 5,0 7.4 8.5 9.2 1.8 Number of mesophilic aerobes. and the result. aerobic microorganisms, CFU in 1 g, no more 2.8 · 10 ^-5 320 120 not detected not detected Specific energy consumption, W hour / kg - 290 310 1300.0 160,0

Claims (1)

A method of inactivating anti-nutritional substances and increasing the nutritional value of soybeans, including treating grain with thermal energy in the first stage and microwave energy in the second, characterized in that in the first stage, whole beans with their own humidity are heated with hot dry air with a temperature of 180-200 ° C to a temperature 95-100 ° С, at the second stage they provide a temperature gradient of 10-15 ° С per second by exposure for 1-2 s with a microwave field with a specific power of at least 35 kW / kg with an electric component of electromagnetic a field of at least 200 V / cm, followed by exposure for 20-30 s in a decreasing microwave field without changing temperature.