火龙果粉冷冻-真空微波干燥工艺优化及贮藏品质

为优化火龙果粉的冷冻干燥结合真空微波干燥工艺并研究其贮藏品质，以火龙果为原料，以复水比和维生素C 保留率加权转化的综合评分为指标，通过单因素和响应面试验优化火龙果粉的工艺条件并分析其贮藏品质。结果表明，优化后的工艺条件为采用冷冻干燥将火龙果干燥到水分含量35% 后，再采用真空度40 Pa、微波功率1 500 W 的真空微波干燥继续将其干燥至水分含量3.5%。该条件下，产品实际综合评分为85.17，与理论预测值基本吻合。联合干燥技术的产品在25 ℃、相对湿度65% 的条件下贮藏30 d 时，火龙果粉中的VC 保留率为（83.36±0.65）%，感官评分65.6，VC 的保留率和感官评分均较高，具有较好的贮藏品质。

Freeze Drying Combined with Vacuum Microwave Drying Process and Storage Quality of Dragon Fruit Powder

The freeze-drying combined with vacuum microwave-drying process and the storage quality of dragon fruit powder were studied.With the comprehensive score of weighted rehydration ratio and VC retention rate as indicators，the preparation technology of dragon fruit powder from fresh dragon fruits were optimized by single factor and response surface tests，and then the storage quality of the powder was investigated.The preparation conditions were optimized as follows：dragon fruits were first freeze-dried to reach the moisture content of 35% and then dried by vacuum microwave at 40 Pa vacuum and 1 500 W to reach the moisture content of 3.5%.Under these conditions，the comprehensive score reached 85.17，consistent with the predicted value.The products prepared with the combined drying technology were stored at 25 ℃and the relative humidity of 65% for 30 days，and the dragon fruit powder showed the VC retention rate of（83.36±0.65）% and the sensory score of 65.6，which indicated good storage quality.