不同干燥工艺下紫薯全粉品质分析

为筛选出适合工业化生产的高花色苷含量低糊化度的紫薯生全粉制备工艺，对单一型热风干燥、微波干燥及复合型热风联合微波干燥等技术下制作紫薯全粉的花色苷、糊化度、感官评分、综合评分等指标数值变化进行测定和分析。结果表明：最优单一热风干燥条件为40°C干燥8 h，此时紫薯全粉花色苷含量1.648 mg/g，糊化度23.39%，综合得分为97.01分，生产出的紫薯生全粉品质好但耗时久；最优单一微波干燥条件为420 W干燥10 min，此时紫薯全粉花色苷含量2.645 mg/g，糊化度高达93.33%，此时综合得分为82.00分，微波干燥法制得的紫薯全粉普遍糊化度过高，不适宜用作紫薯生全粉生产；最优热风联合微波干燥条件为热风温度50°C干燥水分含量40%时转换280 W微波干燥至水分含量8%以下，花色苷含量为1.161 mg/g，糊化度为59.11%，该法制得紫薯全粉综合评分为84.04分。热风联合微波干燥操作控制简易，能在大幅缩短干燥时间的前提下保证紫薯生全粉的品质，适用于工业化快速生产。

Quality Analysis of Purple Sweet Potato Flour under Different Drying Processes

The research is aim to screen out a technology which is suitable for producing a kind of raw purple sweet potato flour (RPSPF) with high anthocyanin content and low gelatinization degree (GD) in industry. Therefore, the changes of anthocyanins, GD, sensory score and comprehensive score of purple sweet potato flour (PSPF) prepared by hot-air drying (HD), microwave drying (MD), and combined hot-air and microwave drying (HD-MD) were measured and analyzed. The results showed that the optimal HD condition was 40 ℃ for 8 h. At the moment, the anthocyanin content was 1.648 mg/g, the GD was 23.39%, and the comprehensive score was 97.01 points. It had the best quality but took a lot of time. The optimal MD condition was 420 W for 10 min, the anthocyanin content of PSPF was 2.645 mg/g, the GD rose to 93.33%, and the comprehensive score was 82.00 points. But the GD of PSPF prepared by MD was widely too high to produce RPSPF. The optimal HD-MD was 50 ℃ drying to the 40% moisture content, and then converted to 280 W microwave drying the moisture content to less than 8%. Then the anthocyanin content was 1.161 mg/g, the GD was 59.11%, and the comprehensive score of PSPF was 84.04 points. HD-MD has a simple operation and control. In addition, it can ensure the quality of RPSPF on the premise of extremely shortening the drying time. In conclusion, HD-MD is suitable for rapid industrial production.