青稞全粉挤压米工艺优化及品质研究

Process optimization and quality of highland barley extruded rice

将青稞全粉原料添加碎米粉复配混合后,采用双螺杆挤压改性,使青稞全粉适度糊化和膨化,青稞口感得以改善,且同时保留青稞特有营养元素。采用响应面实验,优化了青稞挤压制粒工艺,得出最佳工艺参数为青稞添加比例为15%、单甘酯添加量为0.6%、水分添加量为22%、挤压糊化区温度为112℃、物料进料量为13kg/h、双螺杆转速为107.5r/min、切割刀转速为1110r/min,最佳工艺产品感官评价得分为94.2分,其中糊化区温度、双螺杆转速、温度和螺杆转速交互作用对青稞米产品影响较显著,制得的青稞米米粒膨化度为1.50,容重0.76g/mL,碱消值为4~5级,糊化温度适中。RVA快速黏度测量结果为挤压后的米粉糊化温度降低,回生值减小。SEM扫描电镜观察到青稞挤压米米粒内部板结,有明显裂痕;DSC差示量热扫描的青稞米吸热减少,热量变化稳定;X-RD结晶测定显示青稞米挤压后晶型由A-型变为V-型晶体,淀粉由玻璃态变为半晶型高弹态,米粒抗回生性较好。质构结果显示青稞米硬度适当,米饭胶黏性和咀嚼性良好。

After mixing the raw materials of highland barley whole flour with broken rice flour and adopting twin-screw extrusion modification,the barley flour can be properly gelatinized and expanded,the taste of highland barley can be improved while the unique nutritive elements of highland barley are preserved at the same time.The extrusion granulation process of highland barley was optimized by response surface test.The optimum technological parameters were as follows:the ratio of adding highland barley was 15%,the amount of monoglyceride was 0.6%,the amount of water was 22%,the temperature of extrusion and gelatinization zone was 112℃.The feed rate was 13 kg/h,the rotating speed of twin-screw was 107.5 r/min.The cutter knife speed was 1110 r/min,the best product score was 94.2 points,among them the gelatinization zone temperature,twin-screw rotcting speed,temperature and screw rotcting speed interaction had significant influence for the highland barley rice product,the expanded degree of the barley grain was 1.5,the bulk weight was 0.76 g/mL,the alkali elimination value was 4~5 grade.The gelatinization temperature was moderate.The gelatinization temperature and the retrogradation value of rice flour after extrusion were decreased after rapid viscosity measurement by RVA.SEM(Scanning electron microscope)observed that there were obvious cracks in the inner plate of rice grains of highland barley extruded rice,and the heat absorption of highland barley rice with DSC differential calorimetry scanning was decreased,the change of heat was stable.X-RD Crystallization test showed that,the crystal form of highland barley extruded r ice c hanged f rom A t ype to V t ype c rystal after extruding,the starch changed from glass state to semi crystalline form and high elastic state,and the grain had better retrogression resistance.The results of rice texture showed that the hardness of highland barley rice was appropriate,and the glueability and chewiness of rice were good.