RESEARCH OF PROCESS OF TOPINAMBUR TUBERS DRYING AT VARIOUS WAYS OF A POWER SUPPLY

Abstract

Topinambur is a valuable vegetable, fodder and medical crop. A medical preparation inulin is contained in it and reach about 80 percent of the dry matter content. Drying is considered as the most effective method of preservation of tubers. Influence of convective, infrared and microwave topinambur tubers drying ways on the content of the total and reducing sugars, and also energy consumption of these methods is investigated. Convective drying of tubers was carried out on laboratory machine at a temperature of 60 degrees Celsius. The FD-230 facility (Japan) was used for infrared drying of tubers. Drying under the influence of microwave radiation was carried out in the microwave machine VT-1650 with a power of 140 W at heating by not higher than 60 degrees. It is established that high specific energy consumption, worked out 1.6-2.5 kilowatt-hour per kilogram, big heat losses belong to shortcomings of a convective drying. During infrared drying moisture removal is possibly at a low temperature (40-60 degrees Celsius) that enables to keep natural color, taste and aroma, and also vitamins, biologically active agents at the level of 80-90 percent from initial raw materials. This technology renders possible to use practically for 100 percent the delivered energy and to get high efficiency. At a microwave drying method the warming up occurs in all volume of a product. Rather low efficiency (60 percent) of transformation of energy of electric current to energy of the microwave field became limitation of this method. In this regard use of the microwave equipment is effectually at humidity lower than 50 percent.