Study On The Technology And Relevant Characteristics Of Spray Drying Powder Grains

This research used red beans, mung beans, millet grains as raw materials to find out theeffect of different pre-treatment process condition on the quality of grains powder. The dryingprocess of spray drying grain powder was optimized, in order to find the best technologyparameter. Testing different indicators of national standards of grains powder product andscreening the best condition to reconstitute spray drying grains powder. The effect of threedifferent drying methods on the physical characteristics of the powder grains, nutrients,micro-struture were studied.Through the research of spray-dried grains powder, and test every indicators of nationalstandard in grains poeder, optimize the conditions of reconsitituted grains powder, anglicizingthe effection of different spray-dried method, we can get the following conclusion:(1) The optimum pretreatment conditions: the optimum liquefaction conditions of themixed powder were determined. Addition of α-amylase, temperature and time were proved tobe0.125%,70℃,20min. The optimum conditions of the mixed powder were proved to be theratio of red adzuki beans, mung beans and millet3:3:4，the adding amounts of white sugar8%and time of stirring30min. The best conditions of spray drying powder grains was that thetemperature of inlet was136℃, the speed of blower was83%, amount of solution pump was44%. Under these conditions, powder grains flour yield was70.28%, the moisture contentwas2.37%, fluidity was8.9cm, wettability was69.52s.(2) Coarse cereals instant powder by the method of spray drying conform to the nationalstandards for instant soybean powder. The best brewing conditions for instant powder grainsis8times dilution, brewing temperature is100℃, and the stirring time is70s.(3) This chapter were tested to find out the quality of grains powder by the way of threedifferent drying methods, including spray drying, vacuum freeze-drying and electric blastdrying. The results showed: color: spray drying> vacuum freeze-drying> electric blast drying. Viscosity: spray drying> electric blast drying> vacuum freeze-drying. The grainspowder after electric blast drying had the maximum moisture content, after highest vacuumfreeze-drying had the maximum content of grains flour protein, after spray-dring hadmaximum content of total sugar and fat. Under scanning electron microscop, the particle ofspray-dried powder grains were in moderate size and intact spheroids, which had benefit onmoisture trapped in the brewing process and the higher rehydration. The powder can restoregrains the organizational structure of the original slurry to the greatest extent, and had betterreconstitution. Comprehensive analysis showed that spray drying method was good enough tomaintain physical properties of the grain powder and retain its nutrients, which made sure thegrains powder reconstituted with better performance and suitable for the industrial productionof cereals powder processing.