Study On Drying Process Of Black Edamame By Combined Microwave And Explosion-Puffing Drying

The product dried by microwave and explosion puffing could retain the original nutrition. It was flavor, fluffy, crisp, convenient and popular. With black edamame as the main raw materials, the combined microwave and explosion-puffing drying was introduced. The main results were such as:Firstly, the effect of hot-air, microwave, combined hot-air/microwave and explosion-puffing, freeze drying was evaluated on black edamame in terms of consumption, the retention of VC and anthocyanin, color, textural characteristics, sensory quality and microstructure. The combined microwave and explosion-puffing drying thus provided lower consumption and better sensory quality which were similar as compared with freeze and microwave drying. Combined microwave and explosion-puffing drying demonstrated significant superiority over hot-air drying to guarantee good producr quality. Hence, combined microwave and explosion-puffing drying could be used as the best drying method producing dried black edmame in industry.Secondly, the influence of blanching, osmotic dehydration with NaCl, freezing and irradiation pretreatment on the quality of combined microwave and explosion-puffing drying for black edamame was studied. The results showed that blanching, osmotic dehydration with NaCl and freezing pretreatment could improve the quality of products, but irradiation pretreatment caused off-odor which deteriorate the quality of black edamame. The suitable condition were blanching time of150s, NaCl of2%-4%and freezing temperature of-27℃.Thirdly, based on the single factor experiment, the Response Surface Methodology (RSM) was adopted to optimize explosion-puffing drying. A mathematical model was established to describe the relationship between water content after pre-drying, puffing temperature and vacuum drying time and water content, a value, hardness and crispness. The optimal processing parameters were pre-drying of30.75%, puffing temperature of100℃and vacuum drying time of98min.Lastly, in order to determine the safe storage conditions, packaged black edamame were stored in different temperature and relative humidity for6month, and the changes of each index were also studied. The increasement of water content, degradation of nutrient content and change of color could be accelerated by high temperature or humidity. This study suggested that the storage conditions of20℃and RH about50%was better suited for keeping black edamame.