摘要:本课题是以紫薯为原料，考察真空干燥、冷冻干燥、喷雾干燥、挤压膨化前后紫薯粉中多糖含量、POD酶活性、可溶性膳食纤维含量、花青素含量、游离氨基酸含量、可溶性蛋白含量、羟基自由基清除率、水分活度、冲调性的变化。其中重点考察挤压膨化物料水分含量对各指标的影响。实验结果得出挤压膨化物料水分含量为15%时效果最好。结果表明，冷冻干燥效果较好，冷冻干燥紫薯粉中多糖含量29.14%、可溶性膳食纤维含量2.42%、羟基自由基清除率85.01%、可溶性蛋白含量0.83%、游离氨基酸含量0.21%、花青素含量5.19%。

关键词 紫薯；冷冻干燥；挤压膨化；可溶性膳食纤维；花青素

Abstract:This topic is based on purple potato as raw material, vacuum drying, freeze drying, spray drying, polysaccharide content in purple potato starch before and after extrusion, POD enzyme activity, soluble dietary fiber content and anthocyanin content, free amino acid content, soluble protein content, hydroxyl free radical clearance rate, water activity and the tonal change. Which focuses on extrusion material moisture content on the effects of every index. Experimental results on extrusion materials works best when the moisture content of 15%. Results show that freeze drying effect is good, freeze drying of polysaccharide content in purple potato starch 29.14%, soluble dietary fiber content is 2.42%, the hydroxyl free radical clearance rate were 85.01%, 0.83% 0.83% content of soluble protein, free amino acid content and anthocyanin content of 5.19%.

Key words  Purple Potato  Freeze drying  Extrusion  Soluble dietary fiber  Cyanidin