Study On Quality Of White Radish With Far Infrared Vacuum Drying

For conventional vacuum drying equipment exists low drying efficiency, poor quality which can not meet the high moisture fast drying material issues,this paper combined with the method of far-infrared and vacuum drying,using vapor traps and continuous automatic emptying technology,improved design of cryogenic far-infrared vacuum drying laboratory equipment.It can be used for real-time monitoring of material weight, material temperature, heating plate temperature, vacuum degree and energy consumption.The working principle and the design of the overall structure of the low temperature far infrared vacuum drying experiment equipment are described in detail, and the design structure and related parameters of the main working parts are determined.Experimental research on turnip shows that the whole machine structure is reasonable,stable performance, safety and reliability, which can be adapted to the drying of most fruits and vegetables as well as agricultural products, especially solve the problem of fast drying under the premise of ensuring the quality of high moisture content.Secondly,this paper adopted turnip as raw material.Through the study of far infrared vacuum drying of turnip, established the mathematical model of thin-layer drying far infrared vacuum drying of turnip, studied the effects of far infrared vacuum drying of turnip product quality.Using experimental design method of single factor and quadratic general rotary unitized design, explored the influence law of vacuum degree, drying temperature, material thickness to turnip drying time, rehydration ratio, VC content and unit energy consumption and established corresponding mathematical model.In order to ensure the quality of dry products as the main objective,parameters were optimized by using SAS software,target function method and aggregate balance method to determine the best combination of process parameters:When the heating temperature is 68 ℃, vacuum degree is 3250 Pa, material thickness is 7 mm, turnip dry products have the best quality with the dehydration rate is 63.52% / h, rehydration ratio is 3.15, VC content is 2.05 mg/g, unit energy consumption is 6.57 kJ/kg, the comprehensive score is 0.852.Finally,with turnip as material,far infrared vacuum drying, traditional far infrared drying and hot air drying were used in the competitive text,analyzed the changes of its components.Comparative analysis results show:under the same test conditions, the indexes of the turnip samples were obviously increased by far infrared vacuum drying.Dried turnip has well preserved microstructure which can be a truly react the organizational structure of the original sample, color, smell, taste, shape and taste of the sensory quality has been enhanced, the content of VC preservation rate is high, the complex water has better performance,quality of dry products are guaranteed.