蛹虫草复合谷物杂粮膨化产品的工艺优化及糊化特性

Processing Optimization and Pasting Properties of Extruded Cereal Grains with Added Cordyceps militaris

目的:采用双螺杆挤压工艺制备蛹虫草复合谷物杂粮膨化产品,并研究蛹虫草对谷物杂粮膨化产品淀粉糊化特性的影响。方法:以大米粉、糯米粉、薏米粉、红豆粉、黄豆粉、蛹虫草粉为原料,按照一定比例混合制成蛹虫草复合谷物杂粮粉进行挤压膨化实验,并在单因素试验的基础上,选择物料水分含量、螺杆转速、进料速率、挤压温度为影响因素,产品径向膨化率、糊化度、水分含量、吸水性和水溶性指数为指标,设计正交试验,用极差分析法优化出蛹虫草复合谷物杂粮膨化产品的最佳工艺,并利用快速黏度仪测定谷物杂粮膨化产品和蛹虫草复合谷物杂粮膨化产品的淀粉糊化特性。结果:蛹虫草复合谷物杂粮膨化产品的最优工艺参数为物料水分含量16%、螺杆转速180 r/min、机筒的5段挤压温度80-90-120-140-165℃、进料速率15 r/min,此时蛹虫草复合谷物杂粮膨化产品的径向膨化率、糊化度、水分含量、水溶性和吸水性指数分别为3.015、84.32%、6.11%、29.65%、416.39%;与谷物杂粮膨化产品相比,蛹虫草复合谷物杂粮膨化产品峰值黏度、保持黏度、最终黏度、回生值显著下降。结论:蛹虫草复合谷物杂粮膨化产品挤压工艺可行,添加蛹虫草能够显著降低谷物杂粮膨化产品的糊化特征值,并抑制其淀粉分子的回生或重排。

Objective： To investigate the processing of puffed cereal grains with added Cordyceps militaris by twin-screw extrusion and to explore the effects of addition of C.militaris on the starch pasting characteristics of extruded products.Methods： The flours of five cereal grains,rice,glutinous rice,adlay,red mung bean,and soybean were mixed after adding C.militaris powder and then extruded.Using the one-factor-at-a-time method,moisture content,screw rotation speed,feeding rate and extrusion temperature were selected as independent variables for the optimization experiments which were conducted following an orthogonal array design.The responses were radial expansion rate,degree of gelatinization,moisture content,water-absorbing capacity and solubility index.Optimization of the independent variables was done using range analysis.The starch pasting characteristics of the extruded product were assessed.Results： The optimal processing parameters were determined as follows： material moisture,16%; screw rotation speed,180 r/min; extrusion temperature,80-90-120-140-165 ℃; and feeding rate,15 r/min.Under these conditions,the radial expansion rate,degree of gelatinization,moisture content,water-absorbing capacity and solubility index were 3.015,84.32%,6.11%,26.65%,and 416.39%,respectively.The rapid visco analyzer（RVA） results revealed that peak viscosity,hold viscosity,final viscosity and setback were reduced significantly in the extruded product after adding C.militaris,while peak time was increased significantly.Conclusions： The extrusion technology was feasible.Moreover,addition of C.militaris could significantly decrease starch pasting characteristics and inhibit starch retrogradation and molecular rearrangement in extruded cereal grains.